LS heads

[yukonkink03]

I see a lot of used heads on Craigslist. What's the difference between 862-241,243-799, 317 and so on?

 

[zraffz]

Those are the last 3 numbers on the casting.
They decipher what the heads are off of. Depending on what you are looking to do you can gain some flow, compression or both; either will make additional HP.

 

[yukonkink03]

Yea, mine are 862's. I guess I was curious what would be an upgrade over a stock 5.3 head on an 03.

 

[Tonyrodz]

862's were on my 4.8, and iirc my 6.0 has 317's.

 

[swathdiver]

I think there's more than that and not all can swap back and forth. The chambers on some may be larger than the bores on some blocks. If the opposite is true you could run them or open them up to match. I think there's some good info in a pdf you can download by googling "rebuilding gen iv ls engines".

 

[zraffz]

I think there's more than that and not all can swap back and forth. The chambers on some may be larger than the bores on some blocks. If the opposite is true you could run them or open them up to match. I think there's some good info in a pdf you can download by googling "rebuilding gen iv ls engines".

I'm not familiar with the 4.8 or even modifying the 5.3 but AFAIK the issue starts with the 6.2 heads on a 5.3/4.8 because of the bore.