Look up Camster's thread on his new car. Puts down over 640 rwhp through an auto with MAST LS7 heads. Kind of hard to argue with his success.

Considering what a full 427 build is going to cost, I would not make your head decision based solely on what intake you currently own.

 

I already own the shortblock. My ls1 has the intake. I'm already 9k into this project.

 

Do you have a FAST 102 cathedral intake?

And you don't want another head except a cathedral head? Am I understanding you correctly?

 

Yeah, I might as well make do with what I have. Gm hightech had an article on cathedral vs rectangular and it looks like cathedral is best for mid range.

 

Look up Brian Tooley's 454 thread or some of Tony Mamo's thread's they are both full of information about cathedral port heads. Pick one and get a custom cam.

If I was in your shoes I would go with cathedral port heads. I like what I've seen regarding their builds. The choice is yours which way you want to go, but I say cathedral port all the way more over if you already have a cathedral FAST.

Is this a street car? A little more info might be useful. The midrange from a properly set-up big cube cathedral port motor will be an absolute street monster.

Better have a nice suspension and tires

 

1 drive it around 3 days out of the week and I usually race once a month at the track. I think the cam I got is good for cathedrals.

 

ohhhhh yaaa now your talking all pro wcch !!

 

Then you guys have seen some pretty shitty combos...... I have built two combos with there heads that have done quite nicely... One with there 2.5 heads on a 402. 10.7 to 1 compression, 9 inch rear with 3.40ish gearing, 28 inch tall tires (not an optimal combo thru the lights). Full weight show camaro that ran 10.90 first time at the track (2500 DA). No AFR, timing or shift point adjustments.... Second run spinnnn... Now an easy 10.70 car with adjustments and newly regeared...

Second combo makes 607 rwhp thru a 4l80e tranny and 12 bolt...expecting 620 now with higher flowing cat converters and vacuum pump. That's about as good as it gets with out mechaical roller and Single plain manifold (50 more) easy with those two.... That again is heavy rotating auto, not a manual car with stock rear end...

I've seen a lot of shitty combos with all the head manufactures. Most issues were overcamming and to low of compression to work correctly as an effective air pump...


LS7 style heads....Mast, WCCH, All Pro, PRC. Cath heads try... Mast (11 degree stuff), Trick Flow, AFR, PRC...

 

If budget is not an issue....

Rect. Port Intake (Single), LS7 Heads (AI's, MAST, ALL-Pro), Big TB and TUNE.

 

I think I might just go 245cc AFR.

 

An out of the box AFR 245 would work great.....

Turn key 350+ CFM head with a reasonable cross sectional area will produce a really good looking power and torque curve.

If the budget permits and your looking for more I could help you with a "Mamofied" version of that head that flows close to 370 CFM's. Its a one off piece I do by hand obviously with an aftermarket lighter valve, custom valvejob, and hand massaged to completely optimize the port, new valvejob, and chamber design.

Same head I ran on my "Vader" build which produced one of the highest normally aspirated numbers I have seen thru a FAST intake which of course was fully ported and I would want to help you with that as well if you were thinking of going this route. Without a really good intake, you wont tap into the full potential of this cylinder head.

Bottom line, like others have mentioned, a really good cathedral set-up will make similar peak power as a really good square port set-up, but have a much fatter and much flatter torque curve as well, and the part throttle stuff on the street is noticeably stronger with the cathedral design.....some of that due to the longer runner length in that style manifold, not just the smaller CSA of the actual intake ports.

PM me if you have any questions or want to learn a little bit more about what Im suggesting.

This is build I was referring to above in the event you hadn't seen it yet with the reworked AFR 245's

https://ls1tech.com/forums/generatio...ker-ready.html

Thanks,
Tony