Dyno Results for 327 LT-1
07-13-2006, 07:29 PM
#1
Le Mans Master
Thread Starter
Dyno Results for 327 LT-1
Had the chance to dyno my car yesterday, it was warm, hot and humid, but the show must go on. After staging, waiting etc, my pulls were made with the fan clutch fully engaged. It was howling like a flex fan 
. But, real world at work. I am happy with my results, and have not really had any time to go over them in detail. The rally is going on here this week, and I am leaving town in the morning for Spearfish. But, I thought I would post this as a follow up to my recent rebuild.
The torque is there, and it makes power past 7200 RPM.
The first pull is labeled DYNORUN.001 (2:34:22)
First run, first time on the dyno, I was in the drivers seat so I backed off around 6800 RPM, and you can see the power takes a dive. I am not sure how the numbers are recorder, but he would start it when I gave him the thumbs up, and he marked it, when I let off the gas. So, on the first pull, I think he locked 7000 RPM a tad late.
The second pull was done in Second Gear. Marked 2ndgear.001
I ran it to 7250 and if you note, the power is less, but not a "Falling of the cliff effect".
Third pull (4thgear.001) was fairly in line with the first.
Motor is - LT-1 cam, FM-992 lifters, Manley full race flow valves, pocket ported 2.02/1.60 original heads, 327 / 4.020 speed pro pistons, with Crower sportsman full floating rods/pistons, GM (Z-28/LT-1 High pressure oil pump). Stock crank, Luk Clutch, w/L88 (15 lb) flywheel. Stock winters intake (365 hp) and 2818Holley Carb.
The fellow running the computer said I went lean at the top end? Other then that, I think I had that Holley dialed in pretty good.
All the pulls were made with the stock items on the car, air cleaner (paper element), fans, shrouds, normal traffic temp (190-200), stock fuel pump, jetting, etc.
Here are some pics of the text/graphs
. But, real world at work. I am happy with my results, and have not really had any time to go over them in detail. The rally is going on here this week, and I am leaving town in the morning for Spearfish. But, I thought I would post this as a follow up to my recent rebuild. The torque is there, and it makes power past 7200 RPM.
The first pull is labeled DYNORUN.001 (2:34:22)
First run, first time on the dyno, I was in the drivers seat so I backed off around 6800 RPM, and you can see the power takes a dive. I am not sure how the numbers are recorder, but he would start it when I gave him the thumbs up, and he marked it, when I let off the gas. So, on the first pull, I think he locked 7000 RPM a tad late.
The second pull was done in Second Gear. Marked 2ndgear.001
I ran it to 7250 and if you note, the power is less, but not a "Falling of the cliff effect".
Third pull (4thgear.001) was fairly in line with the first.
Motor is - LT-1 cam, FM-992 lifters, Manley full race flow valves, pocket ported 2.02/1.60 original heads, 327 / 4.020 speed pro pistons, with Crower sportsman full floating rods/pistons, GM (Z-28/LT-1 High pressure oil pump). Stock crank, Luk Clutch, w/L88 (15 lb) flywheel. Stock winters intake (365 hp) and 2818Holley Carb.
The fellow running the computer said I went lean at the top end? Other then that, I think I had that Holley dialed in pretty good.
All the pulls were made with the stock items on the car, air cleaner (paper element), fans, shrouds, normal traffic temp (190-200), stock fuel pump, jetting, etc.
Here are some pics of the text/graphs
07-13-2006, 09:46 PM
#3
Le Mans Master
Are you running headers? Top end power seems off for the combination. I'm getting 300 RWHP at 5,700 with the 327/350hp hyd cam (with headers) on my 331 with a less radical setup except I run an RPM manifold an 1/2" spacer and Holly 600 dp.
07-14-2006, 01:35 AM
#4
Race Director
Member Since: May 2000
Location: Redondo Beach USA
Posts: 12,487
Received 1,974 Likes
on
1,188 Posts
The 327 SHP inlet manifold is the limiting factor on Mark's setup, and one of the requirements was to maintain original external appearance. Even to the best NCRS judge its appearance is that of a OE '65 327/365. Though Mark has never had his car judged, with a little detailing I expect it would make Top Flight as it is a very original low mileage car.
All mods are internal and not visible, so it has the OE exhaust manifolds. Dave McDufford's virtually identical configuration that was tested on a lab dyno two years ago did not show a material improvement in top end power with headers compared to the 2.5" manifolds though peak torque increased about eight percent. How much of this increase in peak gross torque would make it to the car with the exhaust system is debatable.
Where do your 80 and 90 percent torque bandwidths start, Todd?
On Marks engine the 90 percent bandwidth is 2400 to 6100, which is about the same as LS7. The pulls started out at two high revs to nail the beginning of the 80 percent bandwidth, but the top is about 6750, which also matches LS7.
Another objective of this project was to obtain as broad torque bandwidth as possible, with the beginning of the 80 percent bandwidth no less than 2000 revs, and this was accomplished.
Also, shifting at 7000 the revs pick up in the next gear at 5500 and within this range, power averages over 270 and is nearly constant.
Everyone needs to look at more than just top end power. This is not a Bonneville car, but a high performance sports car designed for spirited drving and touring, so the entire torque can power curves from off idle to peak revs are important as well as how the shape of the curves interacts with gear spacing.
Duke
All mods are internal and not visible, so it has the OE exhaust manifolds. Dave McDufford's virtually identical configuration that was tested on a lab dyno two years ago did not show a material improvement in top end power with headers compared to the 2.5" manifolds though peak torque increased about eight percent. How much of this increase in peak gross torque would make it to the car with the exhaust system is debatable.
Where do your 80 and 90 percent torque bandwidths start, Todd?
On Marks engine the 90 percent bandwidth is 2400 to 6100, which is about the same as LS7. The pulls started out at two high revs to nail the beginning of the 80 percent bandwidth, but the top is about 6750, which also matches LS7.
Another objective of this project was to obtain as broad torque bandwidth as possible, with the beginning of the 80 percent bandwidth no less than 2000 revs, and this was accomplished.
Also, shifting at 7000 the revs pick up in the next gear at 5500 and within this range, power averages over 270 and is nearly constant.
Everyone needs to look at more than just top end power. This is not a Bonneville car, but a high performance sports car designed for spirited drving and touring, so the entire torque can power curves from off idle to peak revs are important as well as how the shape of the curves interacts with gear spacing.
Duke
Last edited by SWCDuke; 07-14-2006 at 01:52 AM.
07-14-2006, 03:00 AM
#5
Le Mans Master
Thread Starter
I will scan the Air Fuel chart for evaluation, but the tech guy said I went lean after about 3500-4000 Revs.
That may have effected the top end numbers, but as Duke mentioned, the intake is less then Ideal. My constraints were to maintain the use of all the stock items. (Block, heads, intake, covers, carb exhaust, etc). This is the original motor, drivetrain, dist, etc. Albeit I have a few mods, they are bolt on in nature.
The big numbers are not as important to me as where the numbers are on the chart, and the torque curve is about as flat as it can get.
The engine I built is much more pleasant to drive then when it had the 30-30. I am even thinking about pulling the 4:11's out and putting the 3:36's back in.
Shifting around town with the 4:11's is a 1st to 4th event?
But, I was not willing to sacrifice the ability to rev to 7000 RPM and listen to that little motor scream, and it does.
The idle is identical to the 30-30. The next test is going to be the Drag strip.
IF anyone has a way to host a video, I have a video of the dyno, that is pretty cool.
Mark
That may have effected the top end numbers, but as Duke mentioned, the intake is less then Ideal. My constraints were to maintain the use of all the stock items. (Block, heads, intake, covers, carb exhaust, etc). This is the original motor, drivetrain, dist, etc. Albeit I have a few mods, they are bolt on in nature.
The big numbers are not as important to me as where the numbers are on the chart, and the torque curve is about as flat as it can get.
The engine I built is much more pleasant to drive then when it had the 30-30. I am even thinking about pulling the 4:11's out and putting the 3:36's back in.
Shifting around town with the 4:11's is a 1st to 4th event?
But, I was not willing to sacrifice the ability to rev to 7000 RPM and listen to that little motor scream, and it does.
The idle is identical to the 30-30. The next test is going to be the Drag strip.
IF anyone has a way to host a video, I have a video of the dyno, that is pretty cool.
Mark
07-14-2006, 04:27 AM
#7
Le Mans Master
Originally Posted by ghostrider20
IF anyone has a way to host a video, I have a video of the dyno, that is pretty cool.
Mark
Mark
if you want to send me the video I can host it for you on my website
Barry
07-14-2006, 05:47 AM
#8
Drifting
Member Since: Mar 2005
Location: Iowa
Posts: 1,300
Likes: 0
Received 0 Likes
on
0 Posts
Impressive Looks lean between 3k and 3.6k rpm. You said above that the technician said it was lean at the top end, just a typo? Any idea what caused the torque spike down at 3.7K?
Being a controls engineer and car guy, I've designed a couple dyno control systems and am curious, what make dyno was used? How did they measure A/F ratio? If they used an O2 sensor, where did they mount it? Any other parameters measured such as exhaust temp?
Being a controls engineer and car guy, I've designed a couple dyno control systems and am curious, what make dyno was used? How did they measure A/F ratio? If they used an O2 sensor, where did they mount it? Any other parameters measured such as exhaust temp?
07-14-2006, 11:40 AM
#9
Race Director
Member Since: May 2000
Location: Redondo Beach USA
Posts: 12,487
Received 1,974 Likes
on
1,188 Posts
Mark told me it was a Dynojet 248C, which is the most common type in use and my experience with them is good, but I don't know how A/F was measured.
I suspect there is a measurement problem with the A/F ratio. It went so lean off the chart that the engine should have misfired, and this would have dropped the torque way off - much more than the little dip at 3700, which is almost the point where the A/F returned to normal.
From 4500 up the range is 12.5-13.5:1, which is okay, but half an A/F average richer in this range would be a little better - won't show a major difference in power, but is "safer"; 13.5 is about as lean as I like to see at the top end, and denser air in cooler weather will lean it out accordingly.
I can't transform the above advice into jet/power valve changes to the Holley since I'm not a Holley guy.
If anyone else has dyno curves for 327s, please post them, along with details of the configuration including overbore, if any, and dyno type. Comparisons of torque characteristics will be interesting and instructive, and please limit it to 327s. Larger engines will have higher torque characteristics, and it's not an apples to apples comparison.
If you don't have graphs to post, summarize the results by posting the 80 and 90 percent torque bandwidths, peak torque, and peak power.
My computer is coming down today for a major upgrade. Hope I'll be back online this evening.
As stated the objective of this project was to obtain as flat a torque curve as possible from off idle to at least 7000 while maintaining the OE appearance and idle characteristics of a '65 L-76.
I'm still amazed at the results. Peak torque and power were within my estimates of "about 270", but I didn't expect the torque curve to be so flat, especially on the bottom end.
When it comes to street hiperf engines, it doesn't get any better than this.
Duke
I suspect there is a measurement problem with the A/F ratio. It went so lean off the chart that the engine should have misfired, and this would have dropped the torque way off - much more than the little dip at 3700, which is almost the point where the A/F returned to normal.
From 4500 up the range is 12.5-13.5:1, which is okay, but half an A/F average richer in this range would be a little better - won't show a major difference in power, but is "safer"; 13.5 is about as lean as I like to see at the top end, and denser air in cooler weather will lean it out accordingly.
I can't transform the above advice into jet/power valve changes to the Holley since I'm not a Holley guy.
If anyone else has dyno curves for 327s, please post them, along with details of the configuration including overbore, if any, and dyno type. Comparisons of torque characteristics will be interesting and instructive, and please limit it to 327s. Larger engines will have higher torque characteristics, and it's not an apples to apples comparison.
If you don't have graphs to post, summarize the results by posting the 80 and 90 percent torque bandwidths, peak torque, and peak power.
My computer is coming down today for a major upgrade. Hope I'll be back online this evening.
As stated the objective of this project was to obtain as flat a torque curve as possible from off idle to at least 7000 while maintaining the OE appearance and idle characteristics of a '65 L-76.
I'm still amazed at the results. Peak torque and power were within my estimates of "about 270", but I didn't expect the torque curve to be so flat, especially on the bottom end.
When it comes to street hiperf engines, it doesn't get any better than this.
Duke
07-14-2006, 12:57 PM
#10
Le Mans Master
Thread Starter
The "bump" in the AF ratio, or the dip in the torque curve may have been from the 4 barrels opening??
I am wondering if I should increase the rear jets a size or two to richen that circuit up a tad.
Mark
I am wondering if I should increase the rear jets a size or two to richen that circuit up a tad.
Mark
07-14-2006, 01:19 PM
#11
Le Mans Master
This was from before I cleaned up the air cleaner/carb interface or Lars did his carb/distributor magic.
I think that possibly some of the lack of low end was due to the prior distributor curve/timing. Lars made substantial improvements in this area. On his pre-tune-up run, he was able to get a nice burnout in 1st. After his tune-up, the car obviously had more power and he actually got sideways in 1st.
My combination at dyno pull:
331 CI, pump-friendly 9.5:1 CR
K&N 14"x4" air filter, Corvette drop base and lid
Holley 600 dp, choke horn milled, polished
1/2" Aluminum open spacer port matched to manifold, exterior polished
Edelbrock Performer RPM, port matched, exterior polished with all extraneous castings and lettering removed
Homemade lifter valley splash shield to keep hot oil off manifold bottom
Camel hump 1.94/1.50 heads hogged out to 2.02/1.60, pocket ported, port matched, pump-friendly hardened seats, 3-angle valve job
Comp Cams 1.52:1 roller-tip rockers
Crane Cam Vintage Muscle 327/350 hp cam, 222 degrees @ 0.05, 0.447" lift (with 1.50 rockers)
Doug Thorley headers, dechromed and ceramic-coated
2.5" mandral-bent exhaust (including tips), 2" cross-over just before rear axle
DynoMax stainless Ultra Flow mufflers
Mallory Hyfire IV CD ignition box triggered off Accel points
Mallory high voltage chrome coil
Mallory spiral-wound coil wire
Mallory solid copper plug wires, ends soldered to wires
Champion plugs
37 degrees total ignition advance (Lars reduced this to 34 degrees after the pull)
Carter high volume fuel pump
Melling high volume oil pump
Open breathers
Polished aluminum high flow water pump
Flex fan with polished aluminum spacer
Polished aluminum one-wire 100 amp alternator
Muncie M-20 CR 4-speed (Keisler TKO 600 going in now)
Hurst shifter
3.70:1 positraction
225/60/15 Firestone Firehawk SZ50s on 7”-wide Western 30-spoke Turbine Wheels
I think that possibly some of the lack of low end was due to the prior distributor curve/timing. Lars made substantial improvements in this area. On his pre-tune-up run, he was able to get a nice burnout in 1st. After his tune-up, the car obviously had more power and he actually got sideways in 1st.
My combination at dyno pull:
331 CI, pump-friendly 9.5:1 CR
K&N 14"x4" air filter, Corvette drop base and lid
Holley 600 dp, choke horn milled, polished
1/2" Aluminum open spacer port matched to manifold, exterior polished
Edelbrock Performer RPM, port matched, exterior polished with all extraneous castings and lettering removed
Homemade lifter valley splash shield to keep hot oil off manifold bottom
Camel hump 1.94/1.50 heads hogged out to 2.02/1.60, pocket ported, port matched, pump-friendly hardened seats, 3-angle valve job
Comp Cams 1.52:1 roller-tip rockers
Crane Cam Vintage Muscle 327/350 hp cam, 222 degrees @ 0.05, 0.447" lift (with 1.50 rockers)
Doug Thorley headers, dechromed and ceramic-coated
2.5" mandral-bent exhaust (including tips), 2" cross-over just before rear axle
DynoMax stainless Ultra Flow mufflers
Mallory Hyfire IV CD ignition box triggered off Accel points
Mallory high voltage chrome coil
Mallory spiral-wound coil wire
Mallory solid copper plug wires, ends soldered to wires
Champion plugs
37 degrees total ignition advance (Lars reduced this to 34 degrees after the pull)
Carter high volume fuel pump
Melling high volume oil pump
Open breathers
Polished aluminum high flow water pump
Flex fan with polished aluminum spacer
Polished aluminum one-wire 100 amp alternator
Muncie M-20 CR 4-speed (Keisler TKO 600 going in now)
Hurst shifter
3.70:1 positraction
225/60/15 Firestone Firehawk SZ50s on 7”-wide Western 30-spoke Turbine Wheels
07-14-2006, 05:05 PM
#13
Le Mans Master
hey Guys
Mark sent me the video from his Dyno pull.
It's the 2nd pull.
http://69.253.166.197/page1/page64/page64.html
select the first video on the page the link take you on my site.
The file is called: "Marks Dyno pull.mpg"
Mark sent me the video from his Dyno pull.
It's the 2nd pull.
http://69.253.166.197/page1/page64/page64.html
select the first video on the page the link take you on my site.
The file is called: "Marks Dyno pull.mpg"
07-14-2006, 09:52 PM
#15
Safety Car
Member Since: Nov 2000
Location: Clinton Township MI
Posts: 4,750
Received 119 Likes
on
98 Posts
Cruise-In III Veteran
ghostrider20,
Congratulations! Your attention to detail has resulted in some great #s using stock pieces. You got that bad boy to really humm! That has got to be one quick ride. I too would have Luv'd to have been there to hear her hummin @ 7K! I'm a little reluctant to run mine that high...she sure does want to pull after 6K though...
Regards,
Jim
Congratulations! Your attention to detail has resulted in some great #s using stock pieces. You got that bad boy to really humm! That has got to be one quick ride. I too would have Luv'd to have been there to hear her hummin @ 7K! I'm a little reluctant to run mine that high...she sure does want to pull after 6K though...
Regards,
Jim
07-14-2006, 10:29 PM
#16
Safety Car
Originally Posted by BarryK
hey Guys
Mark sent me the video from his Dyno pull.
It's the 2nd pull.
http://69.253.166.197/page1/page64/page64.html
select the first video on the page the link take you on my site.
The file is called: "Marks Dyno pull.mpg"
Mark sent me the video from his Dyno pull.
It's the 2nd pull.
http://69.253.166.197/page1/page64/page64.html
select the first video on the page the link take you on my site.
The file is called: "Marks Dyno pull.mpg"
Dave
07-15-2006, 01:58 AM
#17
Race Director
Member Since: May 2000
Location: Redondo Beach USA
Posts: 12,487
Received 1,974 Likes
on
1,188 Posts
Originally Posted by ghostrider20
The "bump" in the AF ratio, or the dip in the torque curve may have been from the 4 barrels opening??
I am wondering if I should increase the rear jets a size or two to richen that circuit up a tad.
Mark
I am wondering if I should increase the rear jets a size or two to richen that circuit up a tad.
Mark
Send the chart to Lars and Clem Zahrpbsky including your current carb setup - rods, power valve, and secondary opening spring.
We need to talk on the phone about some other details.
My computer is back up and a '62 Corvette is running better tonight. The '62 owner worked on my computer, and I worked on his Corvette. Working on computers is like working on cars. Everything takes twice and long as you think. We missed tonight's cruise, but will get together next Friday to tie up all the loose ends on both my computer and the computer systems engineer's '62 and should be able to make the cruise.
Duke
Duke
07-15-2006, 02:54 AM
#18
Race Director
Member Since: May 2000
Location: Redondo Beach USA
Posts: 12,487
Received 1,974 Likes
on
1,188 Posts
Originally Posted by toddalin
This was from before I cleaned up the air cleaner/carb interface or Lars did his carb/distributor magic.
I think that possibly some of the lack of low end was due to the prior distributor curve/timing. Lars made substantial improvements in this area. On his pre-tune-up run, he was able to get a nice burnout in 1st. After his tune-up, the car obviously had more power and he actually got sideways in 1st.
My combination at dyno pull:
331 CI, pump-friendly 9.5:1 CR
K&N 14"x4" air filter, Corvette drop base and lid
Holley 600 dp, choke horn milled, polished
1/2" Aluminum open spacer port matched to manifold, exterior polished
Edelbrock Performer RPM, port matched, exterior polished with all extraneous castings and lettering removed
Homemade lifter valley splash shield to keep hot oil off manifold bottom
Camel hump 1.94/1.50 heads hogged out to 2.02/1.60, pocket ported, port matched, pump-friendly hardened seats, 3-angle valve job
Comp Cams 1.52:1 roller-tip rockers
Crane Cam Vintage Muscle 327/350 hp cam, 222 degrees @ 0.05, 0.447" lift (with 1.50 rockers)
Doug Thorley headers, dechromed and ceramic-coated
2.5" mandral-bent exhaust (including tips), 2" cross-over just before rear axle
DynoMax stainless Ultra Flow mufflers
Mallory Hyfire IV CD ignition box triggered off Accel points
Mallory high voltage chrome coil
Mallory spiral-wound coil wire
Mallory solid copper plug wires, ends soldered to wires
Champion plugs
37 degrees total ignition advance (Lars reduced this to 34 degrees after the pull)
Carter high volume fuel pump
Melling high volume oil pump
Open breathers
Polished aluminum high flow water pump
Flex fan with polished aluminum spacer
Polished aluminum one-wire 100 amp alternator
Muncie M-20 CR 4-speed (Keisler TKO 600 going in now)
Hurst shifter
3.70:1 positraction
225/60/15 Firestone Firehawk SZ50s on 7”-wide Western 30-spoke Turbine Wheels
I think that possibly some of the lack of low end was due to the prior distributor curve/timing. Lars made substantial improvements in this area. On his pre-tune-up run, he was able to get a nice burnout in 1st. After his tune-up, the car obviously had more power and he actually got sideways in 1st.
My combination at dyno pull:
331 CI, pump-friendly 9.5:1 CR
K&N 14"x4" air filter, Corvette drop base and lid
Holley 600 dp, choke horn milled, polished
1/2" Aluminum open spacer port matched to manifold, exterior polished
Edelbrock Performer RPM, port matched, exterior polished with all extraneous castings and lettering removed
Homemade lifter valley splash shield to keep hot oil off manifold bottom
Camel hump 1.94/1.50 heads hogged out to 2.02/1.60, pocket ported, port matched, pump-friendly hardened seats, 3-angle valve job
Comp Cams 1.52:1 roller-tip rockers
Crane Cam Vintage Muscle 327/350 hp cam, 222 degrees @ 0.05, 0.447" lift (with 1.50 rockers)
Doug Thorley headers, dechromed and ceramic-coated
2.5" mandral-bent exhaust (including tips), 2" cross-over just before rear axle
DynoMax stainless Ultra Flow mufflers
Mallory Hyfire IV CD ignition box triggered off Accel points
Mallory high voltage chrome coil
Mallory spiral-wound coil wire
Mallory solid copper plug wires, ends soldered to wires
Champion plugs
37 degrees total ignition advance (Lars reduced this to 34 degrees after the pull)
Carter high volume fuel pump
Melling high volume oil pump
Open breathers
Polished aluminum high flow water pump
Flex fan with polished aluminum spacer
Polished aluminum one-wire 100 amp alternator
Muncie M-20 CR 4-speed (Keisler TKO 600 going in now)
Hurst shifter
3.70:1 positraction
225/60/15 Firestone Firehawk SZ50s on 7”-wide Western 30-spoke Turbine Wheels
Your torque curve is commendably flat, but it's tough to see the bottom end because the pull started at too high revs. You didn't compute torque bandwidth, but I computed the 80 percent bandwidth as 2500-6000 and the 90 percent bandwidth as 2950-5700, both of which are narrower than Mark's. I've tried repeatedly to get you guys to think "torque bandwith" and understand that it is the best single measure of street engine performance, not "peak horsepower", but it's like pulling teeth!
The broader the torque bandwidth, the better the engine will feel to the driver, and this is usually backed up with absolute performance tests such as quarter mile time and trap speed.
PLEASE, PLEASE, PLEASE start the pulls at 1500. It takes a few hundred revs for the readings to stabilize, but at least if you start the pull from 1500 the reading at 1800-2000 should be meaningful.
When I had my Cosworth Vega dyno tested a couple of years ago, I requested the pull start from 1000, and after some arm twisting of the dyno operator he acquiesed and agreed to start the pull at 1000. The 80 percent torque bandwidth was 1900-7200, 90 percent bandwith was 3000 to 6400. This was with the cams reindexed to my design. The OE indexing torque bandwidths were terrible!
The primary difference in configuration of your engine and Mark's is the cam and manifold. Simulations suggest that a better than OE 327 SHP manifold will add about 15 HP at the top end, which would put Mark's engine up in the 290s without a significant loss of low end torque while maintaining the very flat nature of the power curve from 5500-7000.
Your L-79 cam is giving up fairly early. If your engine had a LT-1 cam the, peak power range would be extended with, perhaps, more peak power. If you feel your bottom end is good enough for 7000 revs, a LT-1 cam would be a good upgrade.
If you shift at 6000, revs drop to about 4700, and my "eyeball average" of power is this range is about 275, which is marginally higher than Mark's average of 270+ from 5500-7000, which is maximum performance rev range with a CR trans and 7000 rev shift points.
Headers may be improving your midrange torque, but, as with Dave's engine, I doubt if your headers are adding meaningful top end power.
Mark's engine performance is limited by the inlet manifold. Yours is limited by the cam.
FI or a single plane manifold should yield top end power well over 300, but it will definitely cost some low end torque, and and mechanical lifter cam would be necessary to exploit the benefits of more top end power, which will be in the very high range up to 7000+.
With Lars' tuning, perhaps you could do some more pulls to establish a new baseline.
Anyone else have any 327 dyno data?
Duke
07-15-2006, 07:40 AM
#19
Advanced
Member Since: Jun 2006
Location: Rockford MI
Posts: 83
Likes: 0
Received 0 Likes
on
0 Posts
No dyno data to share, but one quick question: how does this rear wheel data compare to the originally published data (at the flywheel?) from GM back in the day? Is there some rule of thumb you can use to convert rear wheel numbers to "old school" numbers like "rear wheel torque plus 25%..."?
07-15-2006, 09:17 AM
#20
Race Director
Well I actually strapped mine down to the dyno a few weeks ago. I thought the numbers would be higher but who doesn't? I also know that I was having some wheel spin on the rollers. My setup is as follows
327 block bored .040
350 steel crank mains machined to small journel
Eagle H beam rods
JE Forged flat top pistons
AFR 195 heads
Comp Cams XR282HR roller cam 230/236 510/520 @ .050
Pro Magnum 1.5 roller rockers
Limiting factor of the motor.. L79 intake
Barry Grant Speed Demon 650 w/ mechanical secondaries
Mallory Unilite Dist
MSD 6AL
2.5" ramshorns
2.5" Allens true 2.5" side pipes
Dang.. Can't upload a pdf... Any help guys...
The numbers were 270 hp and 320 tq... Dave
327 block bored .040
350 steel crank mains machined to small journel
Eagle H beam rods
JE Forged flat top pistons
AFR 195 heads
Comp Cams XR282HR roller cam 230/236 510/520 @ .050
Pro Magnum 1.5 roller rockers
Limiting factor of the motor.. L79 intake
Barry Grant Speed Demon 650 w/ mechanical secondaries
Mallory Unilite Dist
MSD 6AL
2.5" ramshorns
2.5" Allens true 2.5" side pipes
Dang.. Can't upload a pdf... Any help guys...
The numbers were 270 hp and 320 tq... Dave