Critique this build. L98
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Critique this build. L98
89 6 spd
Requirements:
-Stock driveability and appearance, parts must be legal
-Pass Ca. smog both visual and tailpipe with no fudging
-An everyday drivers motor-Go anywhere type deal.Somethign anyone can throw together. Nothing exotic, bix bucks, no headwork.
-Max engine speed 5k+-
383
-2 bolt main, ARP bolts
-Scat 9000 crank, scat I beams, Mahle (or?) forged piston
-0 Deck approx 10:1 with 65cc chamber heads
-HR roller cam in the 214-220 @/050 range (undecided)
-180cc head from Kmart
-Roller tip rockers ratio undecided
-Ported to death TPI base, SLP runners with mucho grinding
-Ported plenum
-1-5/8 shorties (if I can find some)
-Aftermarket catback, precats and all size upgraded.
-24-26 lb injectors.
-Stock TB, paper filter, etc.
Your opinions, guestimates, flames etc.
Dont be shy
Go.
Requirements:
-Stock driveability and appearance, parts must be legal
-Pass Ca. smog both visual and tailpipe with no fudging
-An everyday drivers motor-Go anywhere type deal.Somethign anyone can throw together. Nothing exotic, bix bucks, no headwork.
-Max engine speed 5k+-
383
-2 bolt main, ARP bolts
-Scat 9000 crank, scat I beams, Mahle (or?) forged piston
-0 Deck approx 10:1 with 65cc chamber heads
-HR roller cam in the 214-220 @/050 range (undecided)
-180cc head from Kmart
-Roller tip rockers ratio undecided
-Ported to death TPI base, SLP runners with mucho grinding
-Ported plenum
-1-5/8 shorties (if I can find some)
-Aftermarket catback, precats and all size upgraded.
-24-26 lb injectors.
-Stock TB, paper filter, etc.
Your opinions, guestimates, flames etc.
Dont be shy
Go.
Pro
Joined: Feb 2005
Posts: 658
Likes: 1
From: Centerville OH
I like the basic package. 
With the goals you stated, I think a set of hypereutectic pistons would work just fine and save some buckage for other areas of the build.
I know you said no headwork, but I think a set of mild to moderately ported '113s would work very well on a package as mild as this and fits pretty well with the low buck theme.
As you already pointed out, the stock shorty headers really need to go. I know Hedman used to list a stock replacement 1 5/8" shorty header for 84-91 C4's but that goes back a lot of years. I don't know if it's still available or not. The only other choice is to grind all the weld beads flat and radius the flanges, but that obviously doesn't address the basic problem that the tubes are just too small, especially for a 383.
With the goals you stated, I think a set of hypereutectic pistons would work just fine and save some buckage for other areas of the build.
I know you said no headwork, but I think a set of mild to moderately ported '113s would work very well on a package as mild as this and fits pretty well with the low buck theme.
As you already pointed out, the stock shorty headers really need to go. I know Hedman used to list a stock replacement 1 5/8" shorty header for 84-91 C4's but that goes back a lot of years. I don't know if it's still available or not. The only other choice is to grind all the weld beads flat and radius the flanges, but that obviously doesn't address the basic problem that the tubes are just too small, especially for a 383.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Why not next use next size larger KMart heads? 383's suck a lot of air, right?
To keep streetable, keep duration low -- as you propose, but consider higher lift to fill cylinders. At least you'll give whatever head a better chance to suck in the air it needs for the longer stroke 383.
You might need to go 28-30lb injectors. 26lber's were used on the 350 dyno I showed you recently. You saw how lean it was. That car had ported TPiS heads (flowing similar to 180cc KMart's), and a LargeTube TPI. Similar deal -- but with less-demanding 350 underneath.
Consider the CompCams 268XFI with 1.5 rockers. Lifts would be lowered to .535ish. With a good tune and stock config high-flow cats, I'd think you could pass sniffer. Maybe a AFPR could help (quickly) shift AFR leaner for sniff test? (This assumes '89 ODB1 ECM responds slowly to pressure changes).
For keeping budget as low as possible, consider Todd's advise and talk to Lloyd too.
To keep streetable, keep duration low -- as you propose, but consider higher lift to fill cylinders. At least you'll give whatever head a better chance to suck in the air it needs for the longer stroke 383.
You might need to go 28-30lb injectors. 26lber's were used on the 350 dyno I showed you recently. You saw how lean it was. That car had ported TPiS heads (flowing similar to 180cc KMart's), and a LargeTube TPI. Similar deal -- but with less-demanding 350 underneath.
Consider the CompCams 268XFI with 1.5 rockers. Lifts would be lowered to .535ish. With a good tune and stock config high-flow cats, I'd think you could pass sniffer. Maybe a AFPR could help (quickly) shift AFR leaner for sniff test? (This assumes '89 ODB1 ECM responds slowly to pressure changes).
For keeping budget as low as possible, consider Todd's advise and talk to Lloyd too.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Saved this yrs ago cant remember the source
I have not flowed this intake, I did it yrs ago. Noone here will flow it by itself but its taken out pretty far . Exit is 1205, will have to make runner gaskets. It was going to go on a smogger 406 I was going to do yrs ago but I sold the car.
180 uses a 1256 type gasket, 195 a 1205 is close.
Stock.....198.72 cfm
ACCEL.....213.52 cfm
Extrude/ACCEL.....217.11 cfm
Super Ram......220.67 cfm
Holley stealth ram ....275.00 cfm
ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet....251.51 cfm
ACCEL Hi-Flow intake manifold with runner Stock......215.83 cfm
ACCEL......232.53 cfm
Extrude/ACCEL.........243.21 cfm
Super Ram.....240.24 cfm
Extrude-Honed ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet....275.83 cfm
Extrude-Honed ACCEL Hi-Flow intake manifold with ACCEL runner....266.94 cfm
ACCEL.....213.52 cfm
Extrude/ACCEL.....217.11 cfm
Super Ram......220.67 cfm
Holley stealth ram ....275.00 cfm
ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet....251.51 cfm
ACCEL Hi-Flow intake manifold with runner Stock......215.83 cfm
ACCEL......232.53 cfm
Extrude/ACCEL.........243.21 cfm
Super Ram.....240.24 cfm
Extrude-Honed ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet....275.83 cfm
Extrude-Honed ACCEL Hi-Flow intake manifold with ACCEL runner....266.94 cfm
180 uses a 1256 type gasket, 195 a 1205 is close.
Last edited by cv67; Oct 17, 2008 at 02:26 AM.
Race Director
Joined: Sep 2003
Posts: 16,838
Likes: 341
From: Database Error Indiana
Do it. A low budget motor can work out great if the right combo is put together. I built a 355 for my C3 in 85 that my buddies called the K Mart motor. Turned out great. Won a lot of $$$ with it. Put so many miles on it, the last time I freshened it up I'm pretty sure I could have put .040 pistons in the .030 holes. 
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
ah....from the old apartment, now show the pic of the k.table full of allumn. dust.
nothing to add, it sounds like it will meet w/the left coast laws.
on the inj., a 24-26 would be fine...the lean stated above doesn't come from a good inj.
I am posting and then out of here before the "copy and paste, rosseta stone/phoenix schooled one" hatchets the thread.....(my bach. and my masters are in education, and not engineering)
nothing to add, it sounds like it will meet w/the left coast laws.
on the inj., a 24-26 would be fine...the lean stated above doesn't come from a good inj.
I am posting and then out of here before the "copy and paste, rosseta stone/phoenix schooled one" hatchets the thread.....(my bach. and my masters are in education, and not engineering)
Last edited by mseven; Oct 16, 2008 at 08:29 PM.
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Thread Starter
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
1205 2.09 x 1.28
1256 1.99 x 1.23 (180)
runners will be the challenge/weak link.
Anyone have the inside diameter on the accel/AS&M and SLPs?
1256 1.99 x 1.23 (180)
runners will be the challenge/weak link.
Anyone have the inside diameter on the accel/AS&M and SLPs?
Last edited by cv67; Oct 17, 2008 at 02:24 AM.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Can't offer a critique but will offer a shameless plug...
In a week or so I'll have some 5.7" SCAT forged 4340 H-beam rods for sale. I'm building a 383 and am switching to the SCAT Q-lite rods to get more weight out.
$175 shipped. They have less than 10k miles on them. Have them checked, new fasteners and for probably $250 total you have some killer rods.
Will also have some 3/8" 1.6 ratio CompCams ProMagnum roller rockers, self-aligning, ready to bolt on. My AFR heads require non-self aligning.
$220 shipped.
In a week or so I'll have some 5.7" SCAT forged 4340 H-beam rods for sale. I'm building a 383 and am switching to the SCAT Q-lite rods to get more weight out.
$175 shipped. They have less than 10k miles on them. Have them checked, new fasteners and for probably $250 total you have some killer rods.
Will also have some 3/8" 1.6 ratio CompCams ProMagnum roller rockers, self-aligning, ready to bolt on. My AFR heads require non-self aligning.
$220 shipped.
Drifting
Joined: Oct 2006
Posts: 1,934
Likes: 3
From: Citrus Heights California
Why not next use next size larger KMart heads? 383's suck a lot of air, right?
To keep streetable, keep duration low -- as you propose, but consider higher lift to fill cylinders. At least you'll give whatever head a better chance to suck in the air it needs for the longer stroke 383.
You might need to go 28-30lb injectors. 26lber's were used on the 350 dyno I showed you recently. You saw how lean it was. That car had ported TPiS heads (flowing similar to 180cc KMart's), and a LargeTube TPI. Similar deal -- but with less-demanding 350 underneath.
Consider the CompCams 268XFI with 1.5 rockers. Lifts would be lowered to .535ish. With a good tune and stock config high-flow cats, I'd think you could pass sniffer. Maybe a AFPR could help (quickly) shift AFR leaner for sniff test? (This assumes '89 ODB1 ECM responds slowly to pressure changes).
For keeping budget as low as possible, consider Todd's advise and talk to Lloyd too.
To keep streetable, keep duration low -- as you propose, but consider higher lift to fill cylinders. At least you'll give whatever head a better chance to suck in the air it needs for the longer stroke 383.
You might need to go 28-30lb injectors. 26lber's were used on the 350 dyno I showed you recently. You saw how lean it was. That car had ported TPiS heads (flowing similar to 180cc KMart's), and a LargeTube TPI. Similar deal -- but with less-demanding 350 underneath.
Consider the CompCams 268XFI with 1.5 rockers. Lifts would be lowered to .535ish. With a good tune and stock config high-flow cats, I'd think you could pass sniffer. Maybe a AFPR could help (quickly) shift AFR leaner for sniff test? (This assumes '89 ODB1 ECM responds slowly to pressure changes).
For keeping budget as low as possible, consider Todd's advise and talk to Lloyd too.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
180
.200 138 110
.300 198 158
.400 240 190
.500 260 207
195
.200 137 110
.300 196 158
.400 243 190
.500 274 207
.550 280 211
Looks real similar til about .500+
Last edited by cv67; Oct 17, 2008 at 02:23 AM.
Pro
Joined: Apr 2008
Posts: 542
Likes: 0
From: middle of Illinois
if you ask me. I rarely say this, but I'm SO glad I don't live in "Kallie fawn ya" as the governator calls it.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Part of the deal is the SLPs are worse castings which can be less round. Also, SLPs are shorter than the other two options with the added bonus of being able to be siamesed. Kind of makes 'em a good/bad option. With your porting skills though, I'd look hard at the siamesed SLPs.
According to my "research", siamesing them 3" in a fashion such as CorvettePlenum.com does would raise peak 400-500 rpms. Might be something to consider unless total low-end torque is your goal.
One other thing.... another member did a direct comparo with ASM vs SLP. He said ASM tracked .2 seconds faster in the 1/4. He attributed part of the diff to the poor quality of his castings. But they are 12 yrs old. Newer castings may have improved, but I've heard not.
BTW: What you did to that base.... damn nice. Those holes are BIG!
And, for ideas, here's pretty much what I think you're after......
http://www.superchevy.com/technical/...ion/index.html
Last edited by GREGGPENN; Oct 17, 2008 at 03:24 AM.
Team Owner
Joined: Aug 1999
Posts: 24,017
Likes: 634
St. Jude Donor '10
Q: What are the different runner lenghts and port diameters for the different aftermarket TPI runners and bases?
A:
Runner Type
Length (in.)
Port (in.)
Stock TPI
7.250
1.470 round
Lingenfelter/Accel
6.625
1.615 round
SLP cast runners
6.625
1.600 round
TPIS large tube
7.625
1.660 round
TPIS siamese large tube
7.625
1.660 round
Lingenfelter/Accel Super Ram*
4.125
1.870x1.970 "D" shape
TPIS Mini Ram
3.500
2.600x1.350 entry
1.960x1.200 exit
Stock TPI Manifold base
6.375
1.470 round entry
1.960x1.200 exit
TPIS Big Mouth base
6.125
1.750 round entry
2.090x1.280 exit
Lingenfelter/Accel
6.125
1.750 round entry
Super Ram base
2.090x1.280 exit
* Runners only
A:
Runner Type
Length (in.)
Port (in.)
Stock TPI
7.250
1.470 round
Lingenfelter/Accel
6.625
1.615 round
SLP cast runners
6.625
1.600 round
TPIS large tube
7.625
1.660 round
TPIS siamese large tube
7.625
1.660 round
Lingenfelter/Accel Super Ram*
4.125
1.870x1.970 "D" shape
TPIS Mini Ram
3.500
2.600x1.350 entry
1.960x1.200 exit
Stock TPI Manifold base
6.375
1.470 round entry
1.960x1.200 exit
TPIS Big Mouth base
6.125
1.750 round entry
2.090x1.280 exit
Lingenfelter/Accel
6.125
1.750 round entry
Super Ram base
2.090x1.280 exit
* Runners only
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Thanks, Surf. My concern on the SLPs is getting to the inside turn without cutting them open. If I remember right on the stockers it was near impossible so no matter how much I ground on them if that was unreachable it would be for naught.
Are the Accel/AS&M tubes real thin like stock or is there a little extra material there?
http://www.superchevy.com/technical/...ion/index.html
458hp and 534 ft lbs
I understand those are optimized with no accessories, etc but thats basically what Im after, endless torque without all the rumpity rump drama that goes along with it .
Are the Accel/AS&M tubes real thin like stock or is there a little extra material there?
http://www.superchevy.com/technical/...ion/index.html
458hp and 534 ft lbs
I understand those are optimized with no accessories, etc but thats basically what Im after, endless torque without all the rumpity rump drama that goes along with it .