for the past year. i thought my truck was a 5.3..i just took the heads off to do my heads and cam swap, and low and behold..FLAT TOP PISTONS!! so its a 4.8!! FML!! so my question is, is the cam in my sig ok to run?? i got 243 heads milled only .20..so i actually have a little more room for valve clearance then if i was to use the stockers..i just dont want the vales to be slapping the pistons. i hope the cams not too big..

 

You should be fine do the fact is that 243 have a bigger combustion chamber 64cc milled .20 you should be 61cc something like that and stock head is 58cc. Your safe.

 

well thats good to know. thanks. i had these heads based off a 5.3 when i had the work done to them. so i wasnt sure if they would work on the 4.8 or not. i know that my machinest didnt want to milled them to .30 because he said with the cam im using, the valves and pistons were extremely close to contacting. so now that i found out i have a 4.8, i was kinda leary

 

well...
i can fix your dilemma
give me your heads and lets see how they do on a 4.01cylinder flat top
pistons !


i can trade you for some stock 706 heads

 

haha. i dying to see what these heads will do..ive got about 1100 in machine work and another 550 i paid just for the heads. they flow sheet looks better then any on the market head you can get. ill have to post a pic in my build thread of the flow/build sheet

 

i decided to keep the heads tho and im just going to find a 6.0 block and get rid of this 4.8..easy and worthy fix to the problem.

 

 

I think you should put a little turbo on there and give it a whirl...seems to run something like 10.3 at 130, no big deal....