XE268 vs XE274
03-24-2017, 04:46 PM
#23
Melting Slicks
I'm about to choose between these two cams for a (edit: non-roller block) 383. Heads are Edelbrock 60899, 2.02/1.60, Static CR is about 10.3. 3.08 rear, Muncie. Intake Z28 Aluminum, Holley carb., Rockers 1.5.
Head Flow Numbers:
Valve Lift Intake Exhaust
.100'' 63 51
.200'' 124 94
.300'' 181 128
.400'' 227 146
.500'' 253 157
.600'' 253 163
.700'' N/A N/A
Flow Numbers as tested by Edelbrock's SuperFlo SF-1020 flow bench @ 28'' H2O
Roller cam is NOT in the budget and is NOT an option.
Anybody who has direct personal experience with these cams have a good reason to pick one over the other?
(Also- my wife will drive the car occasionally)
Head Flow Numbers:
Valve Lift Intake Exhaust
.100'' 63 51
.200'' 124 94
.300'' 181 128
.400'' 227 146
.500'' 253 157
.600'' 253 163
.700'' N/A N/A
Flow Numbers as tested by Edelbrock's SuperFlo SF-1020 flow bench @ 28'' H2O
Roller cam is NOT in the budget and is NOT an option.
Anybody who has direct personal experience with these cams have a good reason to pick one over the other?
(Also- my wife will drive the car occasionally)
Remember the more cubes you have, the bigger the cam needs to be.
Not saying the XE-268 won't work,.....just that the XE-274, with his compression,...would work better. I got about 15.5 mpg in the 406 with that combo.
On a side note, I've built dozens of smallblocks over the years, all flat tappet cams, and the XE-274 was the only one I ever flattened during break in. It was around the time everyone was having the same issues, and blamed the oil...The same exact engine, with the XE-284, broke in the same way,....was fine. Go figure..........
Last edited by The Money Pit; 03-24-2017 at 04:47 PM.
03-25-2017, 08:15 AM
#24
Le Mans Master
Thread Starter
03-25-2017, 08:22 AM
#25
Le Mans Master
Thread Starter
The 406 I built with the XE-274 had AFR 195 heads, headers and custom duals, 3.70 gears.....but a 700r4 with a 2200 stall. So yes,..the gears helped off the line. The upper rpm was about 5500 as I said, and I could shift between park and drive at 650 rpms and hear no change in the idle speed,...sounded like any other Camero or Mustang on the road. That's what I mean by sounded stock.
Remember the more cubes you have, the bigger the cam needs to be.
Not saying the XE-268 won't work,.....just that the XE-274, with his compression,...would work better. I got about 15.5 mpg in the 406 with that combo.
On a side note, I've built dozens of smallblocks over the years, all flat tappet cams, and the XE-274 was the only one I ever flattened during break in. It was around the time everyone was having the same issues, and blamed the oil...The same exact engine, with the XE-284, broke in the same way,....was fine. Go figure..........
Remember the more cubes you have, the bigger the cam needs to be.
Not saying the XE-268 won't work,.....just that the XE-274, with his compression,...would work better. I got about 15.5 mpg in the 406 with that combo.
On a side note, I've built dozens of smallblocks over the years, all flat tappet cams, and the XE-274 was the only one I ever flattened during break in. It was around the time everyone was having the same issues, and blamed the oil...The same exact engine, with the XE-284, broke in the same way,....was fine. Go figure..........
03-25-2017, 09:32 AM
#26
Melting Slicks
With that small of a gear I'd run the 268. Let's face it with today's cars your Vette isn't going to win any races with a 268 or a 274. So make it a nice driver with the best driveability and enjoy.
03-25-2017, 09:56 AM
#27
Le Mans Master
I have an engine "break in" stand just for that reason. I can iron out all of the bugs before I drop it in the car. The idle is a big determining factor. 650-750 I can live with. 850-1000 I can't- for this particular project. Yes... 350 vs 383 is a little bit of apples & oranges so I have to tread carefully here.
For that low of an idle rpm and the stock like driveability, out of those two cams, I would use the XE268, and even then, it's not going to idle "smooth"....it will drive plenty nice enough tho.
I have an XE268 in a 9-1 358" and it idles very nice, but I wouldn't call it "smooth", as in factory smooth. Hell my 327/350hp cam doesn't idle "smooth" in a stock 350, but it will idle at 650-700rpms.
With that size cam, your 383 will feel like a 350...other then a bit more torque at <3k.
Xe268 sound clip for you...
Last edited by ajrothm; 03-25-2017 at 10:05 AM.
03-25-2017, 10:00 AM
#28
Melting Slicks
I agree with the above poster about using the 268 with those 308 gears....the extra low end torque will be needed with those gears.
I'm not going to talk about a roller cam, but I do recommend you find some really wimpy worn out valve springs and breakin the cam with those. If your able to break it in without flatening a lobe you'll have some good times driving it around....
I'd check out the oil thread in the stickys above for the right oil to use.
I'm not going to talk about a roller cam, but I do recommend you find some really wimpy worn out valve springs and breakin the cam with those. If your able to break it in without flatening a lobe you'll have some good times driving it around....
I'd check out the oil thread in the stickys above for the right oil to use.
03-25-2017, 10:41 AM
#29
Le Mans Master
Thread Starter
For that low of an idle rpm and the stock like driveability, out of those two cams, I would use the XE268, and even then, it's not going to idle "smooth"....it will drive plenty nice enough tho.
I have an XE268 in a 9-1 358" and it idles very nice, but I wouldn't call it "smooth", as in factory smooth. Hell my 327/350hp cam doesn't idle "smooth" in a stock 350, but it will idle at 650-700rpms.
With that size cam, your 383 will feel like a 350...other then a bit more torque at <3k.
Xe268 sound clip for you...
https://m.youtube.com/watch?v=B9dI91DTUeU
https://m.youtube.com/watch?v=JIgLKvG9VQI
I have an XE268 in a 9-1 358" and it idles very nice, but I wouldn't call it "smooth", as in factory smooth. Hell my 327/350hp cam doesn't idle "smooth" in a stock 350, but it will idle at 650-700rpms.
With that size cam, your 383 will feel like a 350...other then a bit more torque at <3k.
Xe268 sound clip for you...
https://m.youtube.com/watch?v=B9dI91DTUeU
https://m.youtube.com/watch?v=JIgLKvG9VQI
03-25-2017, 11:05 AM
#30
Race Director
03-25-2017, 11:25 AM
#31
Team Owner
You may be on to something there. FWIW, I'm using the XE268 in my L82 refresh. Comp and Summit both recommended that grind.
03-25-2017, 12:12 PM
#32
Drifting
I get it about the money situation and completely understand! After doing the Retro HR on my OEM L-82 block rebuild, It is really very straight forward now versus years ago. Howard's rollers do not require any different distributor gears any longer...same for the fuel pushrod not different than OEM. The only item left is the funky cam button which after much research before my rebuild is blown way out of proportion and again very simple to install and along with a double roller timing chain makes cam "walking" highly unlikely...Again, blown way out of propportion. Gary of LI uses a procedure used now that prevents cam walking without a cam button....
03-25-2017, 06:10 PM
#33
Instructor
If you must go flat tappet ok, but IMO, I'd go with a manufacturer with better quality than Comp Cams.
Isky, Crane or contact Chris Straub. 
Last edited by 71454Chevelle; 03-25-2017 at 06:14 PM.
03-26-2017, 09:51 AM
#35
03-26-2017, 10:25 AM
#36
Team Owner
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St. Jude Donor '05
been bitten 3 times by those couldnt give me another.. not even a roller
interesting discussion on speedtalk about the guy that designed that line of cams..op just pass on those
Last edited by cv67; 03-26-2017 at 10:26 AM.
03-26-2017, 05:50 PM
#37
Le Mans Master
Thread Starter
03-26-2017, 05:51 PM
#38
Le Mans Master
Thread Starter
03-26-2017, 06:03 PM
#39
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St. Jude Donor '05
speedtalk.com probably the best engine tech site lots of mfrs engineers and the usaly forum types
Inquire in their engine tech section someone will put the link out interesting
Think (and probably wrong)over the yrs just about every imaginable grind has been done & today mfrs resort to some gimmick to fire sales back up. Probably just jaded though
Inquire in their engine tech section someone will put the link out interesting
Think (and probably wrong)over the yrs just about every imaginable grind has been done & today mfrs resort to some gimmick to fire sales back up. Probably just jaded though