Cam recommantion 72 /455 low compression
March 11th, 2015 | 02:28 PM
#1
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Joined: Dec 2006
Posts: 282
From: Germany
Cam recommantion 72 /455 low compression
We need cam recommendation for street driven 65 conv. (3800lbs)
72 /455 low compression (8:1-8,5:1) Engine
3,42 gears
Performer manifold
headers & 2,5" system with Super 40īs
Roller tip rockers - CompCam
2000 Stall
currently Cam:
260H CompCam: Overlap of 40.00 Degrees
Duration: 260/260
Duration @ .050" Lift: 212/212
Lift: 0.447/ 0.447
LS: 110°
Strong power with the 260H but we want a little more choppy idle. aka more valve overlap.
What you think about the 268H ( will it work with low compr.)
268H CompCam: Overlap of 48.00 Degrees
Duration: 268/268
Duration @ .050" Lift: 218/218
Lift: 0.456/ 0.456
LS: 110°
or the CompCam XE256H--Overlap of 42.00 Degrees
Duration: 256/268
Duration @ .050" Lift: 212/218
Lift: 0.453/ 0.456
LS: 110°
72 /455 low compression (8:1-8,5:1) Engine
3,42 gears
Performer manifold
headers & 2,5" system with Super 40īs
Roller tip rockers - CompCam
2000 Stall
currently Cam:
260H CompCam: Overlap of 40.00 Degrees
Duration: 260/260
Duration @ .050" Lift: 212/212
Lift: 0.447/ 0.447
LS: 110°
Strong power with the 260H but we want a little more choppy idle. aka more valve overlap.
What you think about the 268H ( will it work with low compr.)
268H CompCam: Overlap of 48.00 Degrees
Duration: 268/268
Duration @ .050" Lift: 218/218
Lift: 0.456/ 0.456
LS: 110°
or the CompCam XE256H--Overlap of 42.00 Degrees
Duration: 256/268
Duration @ .050" Lift: 212/218
Lift: 0.453/ 0.456
LS: 110°
Last edited by STLCRZY; March 11th, 2015 at 02:32 PM.
March 12th, 2015 | 02:12 PM
#3
Thread Starter
Registered User
Joined: Dec 2006
Posts: 282
From: Germany
For this Engine we only need a suggestion.
We contact Mark for a while to give us Cam/Lifter quote for another engine but he doesn't respond..so we buy it for another Cam grinder-maybe to busy or donīt want to ship oversee....however!
Maybe Mark can help with his experience.
We contact Mark for a while to give us Cam/Lifter quote for another engine but he doesn't respond..so we buy it for another Cam grinder-maybe to busy or donīt want to ship oversee....however!
Maybe Mark can help with his experience.
March 12th, 2015 | 05:12 PM
#4
Registered User
Joined: Nov 2008
Posts: 8,004
From: Central Fl
Really? Sorry if I didn't answer a previous post or email. I ship everywhere, sorry.
A single pattern, in early, maybe 106, no more than 108, would be your best option. I'd limit the @.050 duration to no more than 220. I would've recommended an Erson Hi Flow AH (220/220@.050) on a 108, in at 106.
And chop comes from cylinder pressure. Yours will be limited so don't expect too much lope, no matter what.
Hope this helps!!
A single pattern, in early, maybe 106, no more than 108, would be your best option. I'd limit the @.050 duration to no more than 220. I would've recommended an Erson Hi Flow AH (220/220@.050) on a 108, in at 106.
And chop comes from cylinder pressure. Yours will be limited so don't expect too much lope, no matter what.
Hope this helps!!
Last edited by cutlassefi; March 12th, 2015 at 05:20 PM.
March 13th, 2015 | 02:41 PM
#5
Thread Starter
Registered User
Joined: Dec 2006
Posts: 282
From: Germany
Thanks for the helpful reply Mark...
I was very surprised about the choppy idle from the 260H.
The 268H must have a little more chop than the 260H correct?
But will the 268H work with low 8. to 8.5:1 compr.?
268H CompCam: Overlap of 48.00 Degrees
Duration: 268/268
Duration @ .050" Lift: 218/218
Lift: 0.456/ 0.456
LS: 110°
I was very surprised about the choppy idle from the 260H.
The 268H must have a little more chop than the 260H correct?
But will the 268H work with low 8. to 8.5:1 compr.?
268H CompCam: Overlap of 48.00 Degrees
Duration: 268/268
Duration @ .050" Lift: 218/218
Lift: 0.456/ 0.456
LS: 110°
March 13th, 2015 | 03:06 PM
#6
Thread Starter
Registered User
Joined: Dec 2006
Posts: 282
From: Germany
....rememberer me of a 455-story a while back where we went from choppy idle to mild/stock idle. We only replace the new stock low compr. pistons with 2323F Pistons...
Why we loose that lovely idle while we raise the compression??
Think that the 270H was to big for the engines compression but it sounds and drive good :-)
Cam was the 270H from CompCam
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 224
Advertised Duration: 270 int./270 exh.
Intake Valve Lift 0.501 in.
Exhaust Valve Lift 0.501 in.
Lobe Separation 110
Why we loose that lovely idle while we raise the compression??
Think that the 270H was to big for the engines compression but it sounds and drive good :-)
Cam was the 270H from CompCam
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 224
Advertised Duration: 270 int./270 exh.
Intake Valve Lift 0.501 in.
Exhaust Valve Lift 0.501 in.
Lobe Separation 110
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