Justinrst

Hey guys picked up a set of 243 ls6 stage 2 ported heads never milled 64.45cc. I am building a silverado 4.8 70mm turbo truck. How many thousands do I need to mill to get back to 9.47 compresion. 4.8 stock heads are 61cc it is a dog if you lower the CR and aren't in boost all the time. I'm gonna run ls9 head gaskets, not sure what thickness they are. Any help thanks.

Also then what size push rods would I need? I am going to run yella terra 1.7 lightweight rr offset pattern.

Justinrst

any thoughts??

99 Blue Bird

iTrader: (3)

i thought the 4.8s were in the 10.X.1 area cr wise. they have flat tops. the 5.3s have the 9.4.1 cr because of the dished pistons

Silver408z

iTrader: (1)

are you sure ls9 gaskets would be good for your setup? Is the 4.8 the same bore as other lsx?

batboy

iTrader: (6)

Will probably need to cut about 0.020" to be around 61cc. Don't use LS9 gaskets on a 4.8, that's crazy talk.

Justinrst

What don't use the LS9 head gaskets?

It's gonna be a turbo 4.8 at 15psi at all times?

Xaviarrahl

iTrader: (3)

what's the difference with the ls9 gaskets?

Blk98Vert

iTrader: (2)

Use the LS9 gaskets, you won't have issues. They are thick so take that into account when you mill