I disassembled my 5.3 and while I'm waiting on getting machine work done should I port the heads? I'm gonna over bore the block to a 5.7 and my goal is 450-475 crank HP. I'm considering sending the heads to Katech and getting a nice valve job done locally afterwards. I'll be using a cam with 230-235ish duration at .050 and compression should be around 10 to 1 with a LS6 intake. Thanks for any input.

 

At the least I would have a good multiangle valve job done along with bowl blending.
I've read in multiple sources that these operations are the most effective parts of port work.

 

You should go ahead and have them ported since they are off. you will kick yourself later if you don't. just my opinion..

 

prc port from TSP is like $900 ...... seems like a no brainer

 

Tough call. For your goal of ~475HP at the crank I'm not sure you need porting. I bought ported LS6 heads a long time ago and I still kick myself for not upgrading to an aftermarket head.

 

Ah, the should I have gone bigger dilemma. Ported heads are a good idea. But that $900 could go toward a set of aftermarket heads. And then a stroked LS3 block is better than a LS1 block. and so you end up falling deeper and deeper down the rabbit hole.

 

Very true. The rabbit hole is deep! It's going into a Porsche cayman so a NA 5.7 with 475ish crank HP should be plenty.

 

Either way it should make for a fun car to drive.

 

It all comes down to your budget really.

For 900 bucks, I'd rather find a used Fast 92 or 102, sell the Ls6 intake.

Use ls6 intake money for a good flowing exhaust.

Ive had customers go high 10s/low 11s with my ported 243 heads and stock valve job with a 230-236 cam.

My personal opinion is aftermarket heads and valve jobs are overrated.

 

Port those SOBs! You'll be glad you did and ported heads will make more of a difference than a new intake manifold.