Originally Posted By: clinebarger
Thanks to SteveSRT8, LS1mike, & A_Harmon, I appreciate the input!
I hate picking Camshafts, I can narrow it down too 2 or 3 usually...Then I get very indecisive for some reason?
I also really like the 273, But LS1mike is running a very similar cam to the 281....But without as much duration spilt, Which I'm sure works well with his cathedral port heads.
With the rectangle port heads I'm going to run, And I have a few more cubic inches....The 281 will work fine...with a 4000 Stall.
But the 273 would be good with a 3600 Stall.
Back on the engine, I need to order some pistons so the Machine work can be done, I need to "CC" some LS3 heads, But I'm pretty sure with Flat-Tops & GM 6.0L/6.2L head gaskets I will be around 10.1-10.3 compression with a 0.30" overbore...Depending on piston "Installed" height.
The factory LQ9 pistons are ABOVE the deck a few 1000's of an inch, So I need to measure the Pin location to give me a starting point.
For rectangular port heads (L92 or LS3) a larger duration split is recommended to get the exhaust flow to keep up with the intake. Comp's LSr Rectangular Port series of cams are designed for the heads with the 2.16" intake, 1.6" exhaust valves. They have 16 degree longer exhaust duration than intake. Their Cathedral port cams have only 8 degree duration splits.