jacobrobertson2010

Ok fellas. Im looking to put a little more into my little chevy. I have a 99 silverado. As of now its just been freshened up. Bored it and threw some ls1 pistons and rods in there. With a little small cam. I forget the specs but something like 212/216 on 114 lsa. Im running 4.10s with true trac. I have a built 65e and of course fbo. Im thinking of going with the 220/220 or 220/224 on 112 lsa. I will be running a 3200 stall. What heads would you guys recommend. My las lq9 build I went with the prc 5.3 stage 2.5s. Just trying to get opinions. Btw it is extra cab. Any help would be appreciated. Thanks guys

jacobrobertson2010

All these people and no one will comment?

53bowtie

iTrader: (6)

Do you have 5.3 heads on it now? If so you probably want to stay with them for the compression. Also, with the extra cubes and a 3200 converter I would think you could run a 228r or the like.

craigsix

i like my 799s.

jacobrobertson2010

Yes its stock 5.3 heads. Should my compression be close to the same with the stock ls1 pistons vs the stock 5.3 pistons. What would be decent heads to go with using the 228r

53bowtie

iTrader: (6)

No your compression is higher with the Ls1 pistons than it is with the 5.3 pistons. Search on Ls1tech to see what your compression ratio is because I know alot of guys over there put 5.3 heads on their Ls1 to raise compression. That being said, the 5.3 heads have smaller valves and dont flow as well as the 243/799 heads found on Ls6 and newer (07+) 4.8/5.3 engines.

If you swapped to the 243/799 heads you would lose compression but would probably make the power up in the extra flow. If it were me I would run these heads and a high 220's duration cam.

If you are going with ported heads you could probably do the 5.3 heads like you did on your Lq9 because I think they normally put larger valves in when they port them. This would also maintain your current compression ratio.

2008SilveradoGhost95

I have the 4.8 with 243 heads with lunati springs on my 08 extended cab and a 220/220 112 lsa cam in it and it pulls good top end. I'm bout to switch to 4.10s! I'm wanting that 228r cam next though and to port my heads.

batboy

iTrader: (6)

If I'm reading your first post correctly, you have already have the block bored out to LS1 size? If you used LS1 rods and pistons, that means you have true flattop pistons which should help with compression. I'd get a pair of 243/799 heads and mill them about .020" which will give you the same compression chamber size as the 5.3 heads with the added advantage of bigger intake valves and better flow.