I am building a true budget motor for now to replace the tired 4.8. I have a built 5.3 on the stand with a set of 4.8 pistons i had laying around and a comp 212/218 522/529 114 cam i had as well. I realize that the L33 had 243/799 heads and around 9.9:1 CR, but i dont have the cash for 243s right now so i have a choice of cleanin up a set of 241's or the stock 706's. Either one will be slightly surfaced and the runners and bowls mildly ported and smoothed. Any ideas on which to go with, or what kind of CR i would be looking at? Future plans are either a Maggie or a small shot... Thanks alot

 

what's the chamber size of the 241's, I forget but putting the stock heads on there would bump CR up too much.

 

I dont think 4.8L pistons will work in a 5.3L. The 4.8L has a different stroke and rod length. The odds of the resulting required compression height on both pistons being the same on both a 5.3l and a 4.8L are remote.... Although I could be 100% wrong.

 

I believe the 241s have 66 cc chambers which is only 1-1.5 cc more than the 799/243. I would have guessed my CR to be a tad less than 9.9 maybe around 9.5-9.7ish range. But if i keep the 706's i would be close to if not more than 11.1:1. I am leaning toward the 241's due to more boost friendly CR and a larger valve as compared to the 706...and with a "low lift cam" i would see this assisting air flow at the lower lift.....? In other words since the runner is identical on 241 and 706 ill maintain "good" torque and with the larger valve i should surely let more air in at same given lift.



Oh and yes 4.8 pistons will work on a 5.3...as proven in the L33 HO