Doing some contemplation with my Low compression 454 build...
The motor came with stock 781 heads on it... Haven't CC'd them yet so for now we'll assume ~119cc
Contemplating trading for a set of 390 98cc heads.
With this engine setup:
454, 4.370 bore, 4" stroke
Flattop pistons (.080 over) eyebrow valve reliefs)
.02 shim head gasket
Lunati 60203 cam 4degrees advanced
Kettbo estimated the 781's would put it ~8.3:1 comp & with the 390's it would be around 9.6:1
The question is- What would the real world performance difference between them be?
How much HP & Torque would i be giving up staying lower Comp. Can anyone crank out a desktop dyno of the two combos so i can see what the differences look like?
idea is that down the road a year or two if i rebuild this motor and change the pistons i might be glad i kept the 781's. A full go through is not in the budget now, and see no reason the motor can't go back together with shim headgaskets & performance cam and be enough to make me happy for a while. Plus it would be nice to run cheap gas in it... However as i said, if the performance difference is significant, then to hell with the cost of gas
Carb & intake?
Cam's 4°'s over the ground in 4°'s ?
Holley 800 DP
Edelbrock Performer 2.0 gasket match ported
Hedman 65002 Full length 2" primary 3" collector
2 1/2" H-pipe exhaust w/ full tailpiples
Dynomax Super Turbo Mufflers 19" long case
For cam advance this is what was recommended:
X2 on the 60203. Run it on a 103-105 ICL and it'll rip