I have been looking in at getting some 241 or 853 heads off of an LS1 and putting them on my truck. I know that the only difference is the intake valve size, but instead of spending $1100-1400 I thought about going this route. I have 706 heads and if my calculations are correct then I should just have to mill the heads down (.039) and the compression should be back up to about 9.5:1. My only concern is milling them that much. Would this even be possible. Does anyone have any opinions or know anyone that has done this or know a machine shop with some knowledge. Mine local just looked at me and said, "Yeah we'll get it done, you should have any problems, We've milled way more that that before. But we can't be certain."

 

I have also been looking at the 243 heads. Does anyone know specifically what these were on. I noticed that they had a little more compression than the 241's and a little lets combustion chamber cc's. Would these be easier or more difficult to proceed with on my application? Also, do the LS1's use flat top pistons. My only concern is the valve to piston clearance.


ANYONE???

 

243's are a way better breathing head (from what I've read) chamber size is 64cc so they'd have to be milled down, as you already know. 243/799 head castings were found on LS6/LS2 and some 5.3L truck engines (L33 for one).

 

PMed you a link.

 

Thanks guys. Did the LS1's come with flat top pistons? And if I I mill it and stick it on, it should be about stock compression right.

 

Also, I still can not find anything on the valve to piston clearance. Can anyone help me with this part. I did find a machine shop here in town that will mill them for me. It's just finding out about the clearance. I really don't want to have to order them and find out that it will not work. Or have to order some new pistons.

 

Wife wouldn't like the pistons too much. Although, it would be really nice though. Because that can lead to other things.

 

Also, in the link above, what is the difference in the perimeter bolt and the center bolt?

 

GM started putting the 243 "LS2" castings on the Gen IV 5.3s, I wonder how they dealt with compression. Pistons, or milled heads?

 

i had 243's milled .040 with a tr220 cam in my truck before i swapped in the 6.0. if ya want some advise from the been there done that then instead of saving for some heads just find a 6.0 and a cam and move on.