I'm shooting for 400rwhp. My "friend" showed me some ported LT1 heads on ebay that are TEA "stage 2" ported, with 63cc chambers. Doing the math, that will put me at 10.0:1 CR, vs the 11.2:1 I'm going to have with ported LT1 heads milled to 53cc.

How much HP diff will there be in the ~400rwhp range between those CR's?

I hope this makes sense.

 

Since they are TEA's...I would just call TEA themselves, and ask them...

 

I cant remember extactly- but i recall reading that either 1/2 a point of compression or 1 full point is woth about 4% HP.

 

Why not just mill the 63cc ones down?

 

I have heard that it is about 3.5 to 4% as well. On a 400 RWHP, this is 14-16 HP. There was a magazine that tested a BB Mopar and dynoed it with several differnt compression ratios by stacking head gaskets. This would also play with the quench as well as the difference in compression but they cam up with the same 3.5 to 4% that I have always heard.

63 cc seems pretty big for an LT1 head. It could be accurate though.

Lloyd

 

Yeah, 4% for each full point of compression is the general rule of thumb.