Im in the process of building a 403cid for boost (turbo). However, Im stuck on head choices:

PRC 2.5 6.0 head - I like it but with a boosted app Id like to have 356 material and a thicker deck

PRC 225 - I was going to buy these, however after talking to TSP today, the rep said they do not offer porting option for this head if i wanted to sent it back in later down the road.

TFS 220 as cast - (awaiting a call back from TEA)

This is a complete new build to me so I have zero cores to send off to have worked or ported. Id like to shoot for 900rwhp with this motor on a turbonetics y2k 80mm..cam is 230/234 @ .50 with .625 lift..

 

Honestly, I'd look into the LSA heads with a nice valvejob for that setup. They are setup for boost and flow plenty for a turbo setup.

Those other heads are great, but they are expensive and make more sense on N/A setups looking for good efficiency and velocity.

 

I think a rectangle port would be the best option. LS3... loves boost.

 

I was going to do cnc'd ls9's but i want to stick with cathedral port..

 

No sense to stick with cathedral. Hell, L92 heads and an L92/LS3 manifold is cheap. Swap to a lighter intake valve if you want.

 

Of the options you've posted, the TFS 220cc heads are the best option. If you can step up you budget some, got with some TFS 235cc heads. The guys telling you that the cathedral head isn't going to be better than a LS3 style head for boost have it wrong. If you go over to the FI section, you'll see tons of guys making crazy power and laying down super fast ET's with cathedral headed setups. I'll look, but I'm pretty sure the one of the fastest guys on here is running TFS 220cc heads.

 

Most of the heads listed are really good for N/A set up. I wouldn't want high compression right out of the box. The 317 cast heads and L92 heads should keep the compression low and would be good for boost. I am not sure how much it would cost to port them. Might be a cheaper option but not necessarily the best one.

 

Check out this thread. This guy is using 799 casting cathedral heads. You tell to that cathedral heads won't get the job done.

https://ls1tech.com/forums/forced-in...d-falls-2.html

 

I agree with Phoenix...Cathedrals were ahead of their time!

and fwiw, if I was building a boost setup, I would go with higher compression and E85.

 

If you got the TFS 220cc head route, hit up Brian Tooley. He'll give you the best deal possible on them, and he can even do some touch up work to the heads if that's something you'd be interested in. He can also make sure to set the heads up with the appropriate valvetrain for boost.

 

Best Cathedral for 4.0"+ Bore & 4.0 Stroke.
MMS 235 with NFI Exhaust Port Followed by TFS235 with Nitrous
Exhaust Port. Both of these are PREMIUM Priced heads, however
With thicker decks, and great flowing E/I Ratios will make
Huge power with small/medium sized cam (for a 400"+ Engine)
At lower Boost and less Excess heat.
Just my .02

 

At least nobody came in here and said just turn the ****, heads don't matter......

317's have been in the 7's.
Of course it was a Mustang.