I'm really struggling about what to get. I have been researching a lot and have asked some questions that aren't really being answered!

I want to be pretty streetable and have more useable power/tq. I'd really like to make over 430 HP/400 TQ.

Here's the setup:
Stock 346 ci
TSP's 228 R cam 112 LSA
Vengeance ported FAST 90
Headers/True duals
All other supporting mods

Now should I get PRC 5.3 stg 2.5 heads with stock GM head gaskets or PRC LS6's with .040 cometics.

Which one is more suited to my needs? If other, specify.

 

I think the 5.3l with .040 gaskets is the way to go for what you want to do. Also, you can call Texas Speed, Jon was more than willing to help me out and talk to me about my setup

 

Not sure why I think this way but I love compression and I would go with the 5.3 heads with thinner gaskets myself. Thats just how I feel about it. Maybe because I think that it would produce more HP and TQ as far as under the curve is concerned. I could be wrong though.

 

What compression would both of those net?

 

I dunno, but I'm thinking the 5.3's might be better for my needs.

 

I had the TSP LS6's and now have the 5.3's. I felt more power out of 5.3's and wont go back to the LS6's. Although I had to used stock multi-layer gaskets inorder to keep my MS3 cam

 

With your choices I would go LS6 and .040 gaskets over the 5.3's and stock gaskets; however, I went with the 5.3's and .040 gaskets.

 

why not ask tsp they make em

 

I had a similar question, and they recommended the 2.5's; I just placed my order.

 

i got 2.5s the early ones and they rock

 

also depends on your future build plans, running boost applications i would go with the ls6s, less compression good flow numbers....

the 5.3s are going to have a higher compression ratio which makes good power but it is ill advised to run them with a moderate or higher boost application

 

I'd say the 5.3's with .040 cometics.

 

I have the early 5.3 heads, wish i had gone with PRC or Higgins (AUS)
Check what chamber size the heads have,as mine are 67.5cc (way to big) and if they port matched to your inlet manifold now have less compression than Standed, waste of $$$$$$$.

You get what you pay for i guess.

 

I bought my TSP 5.3's in January and will mate them with the Cometic .040's. 59cc chamber, -2.2 piston. Hopefully going in within 2 weeks.

 

when did they swap to the newer style ones. i bought some in the summer of 07. i thought they were saying they were the new ones then but i really didn't know.

 

What pistons are you running?

 

Anyone know the flow numbers on the Exhaust side for the PRC 5.3 stg 2.5?

 

I believe it was in late 2006 they changed to the latest CNC program, dropping the runners down to 220cc.

 

If you stick with that cam you could get those power numbers with STOCK 243 castings w/ .040 cometic head gasket, and an LS6 intake. Seeing that you already have a ported 90/90 intake you shouldn't have any problems. Don't waste your money on true duals, a full cat-back works just as well and doesn't cost you torque.

 

why not get the ls6 heads, get them milled so you have a 59cc chamber and get the .040 gasket. or would you have pv clearance problems