9.8..........5700-5900rpm and 700hp, how much compression is to high? Do these numbers sound good?

Mer
 

MER Performance

4.500” x 4.250” 540 CID

9.6:1 CR

AFR 325 CNC Chamber_Hyd Roller

Correction factor_3.8% (1.038)

717.86 HP @ 5800

Mark commented the engine baseline dyno pull was ~685 and the additional 33 HP was found in the tune w/ the Holley EFI.

Bob

BB28

With a properly designed combustion chamber.9.8 on pump fuel is very doable.

Bob

Would that be with the Cnc afr chamber like we discussed?

Does that mean the combustion chamber needs to be cnc'd? How do you know if is properly designed? What octane pump gas are you talking.....89?

From talking to Bob, CNC is the way to go..

I guess a canfield 320 hard anodized is a great head because we run 10.3-1 and 0 issues on a bunch of 540's.:drink:

yup,everything is more likely to be the same size and volume.

No it does not need to be cnc'do what it means is you have a lot better chance of running higher compression with pump fuel with a combustion chambered designed today than 50 years ago. With the right chamber you can retard ignition timing therefore giving the motor less time to have a chance to detonate. The LS based motor / combustion chambers don't need much timing at all. If memory serves me when I had a conversation with a guy that specializes in LS motors (9 a week) he said because of the chamber design 21 degrees of timing is the sweet spot. 21 degrees of advance has alot less time to detonate than say 36 degrees (15 degrees to be exact). Hope this might shed some light on your question...

this off the ls forum.

Good safe place to start is 26 degrees at peak torque (4800 rpm) and ramping up to 28 degrees by 5600 rpm. You can then experiment with more timing or less. The 26/28 is very common for stock LS1 running 91-93 octane. Don't be surprised if your power doesn't change much with 2 degrees more or 2 degrees less timing. 26-28 degrees is the sweet spot for most stock motors.