I have fbody with a lq9 with ported and polished 243 heads, 3.73 gears, 3600 yank but I'm switching to a 4000 ptc, 90/90 fast, and a tsp 233/239 .595/.603 111lsa I was wondering if this sounds like a strong set up or combo? Is there something I need to change ?

 

What's your compression ratio? That cam is going to respond quite well to compression. I'd suggest aiming for about 11:1

 

How could I aim for a certain ratio? I thought it is what it is? What could I change to bump it?

 

Wasn't this posted in another area as well?

 

If your compression ratio is low, you can have the heads milled to reduce combustion chamber size. If your compression ratio is high, you would need to either swap pistons for dished pistons or swap heads to larger chambers.

Chances are, your CR will be in the 10.5 range.

Download a valve events calculator. It will typically include CR calculations, so you can insert all your engine specs and then you can change the combustion chamber volume to determine what you need to achieve a certain target. Then, take your heads to a machine shop and have them treat accordingly.