Generation IV Internal Engine - 427 lsx need head options

Alright guys Im not really knowledgeable about putting combos together, so I come for help. I have a 427 lsx block with a 4.125 bore,zero decked with a -2.8cc piston. Cam is around 246 254 .6xx .6xx 113 +3. I'm looking for a good set of heads that will give me good streetability for a dd. I think I need 72cc chambers to make 11.5:1 and I have the lsxr intake.

What kind of budget? Are you staying N/A or are you going to spray it?

I would suggest the TFS 23/45 heads from TEA. They flow awesome. You could get the LSXr Port Matched to them for a little more also.

Ls7 heads if you have that nice bore ftw. What lsxr intake are you talking about?

I was going to say a bad ass LS7 head either from Mast or PRC but was waiting to seee budget lol.

WCCH ls7 heads

I'd say wcch or tea, period.

...I have the lsxr intake.

What style of heads is the intake for (ie cathedral, L92, or LS7)?

What style of heads is the intake for (ie cathedral, L92, or LS7)?

This.

Mast or WCCH for rectangular.

Or TEA, AFR(Mamofied), Mast for cathedral port.

i have been looking at the same set up but with a 4.185 bore and 4.00 stroke

i was recommended by a few friends to go with PRCs 285cc LS7 heads,, if any one has experience with those chime in for the op thats looking ,,

i only have experience with stock ported castings

I don't have a budget I just want what would be best. I have a cathedral port intake. Also I've heard the isn't much diffrence between rectangle port vs cathedral port. Am I wrong?

ive been having the same question except its for an lsx 454. i was thinking ls7 or mamofied AFR 245 for mine

I don't have a budget I just want what would be best. I have a cathedral port intake. Also I've heard the isn't much diffrence between rectangle port vs cathedral port. Am I wrong?

Yes, you are wrong. The differences are almost night and day.

With a cathedral port intake, you must use cathedral port heads. AFR and Mast both make very good heads. Personally, I prefer Mast's heads, but AFRs are VERY nice as well.

Peak horsepower might be higher by just a bit on a rectangular port, but from what I have seen on here cathedral ports tend bring more to the table in terms of area under the curve. If you have no budget go with the mast heads but I think a set of AFR's mamofied or not would get you very nice results as well. Since you already have a cathedral port FAST i see no reason to start over just to make the switch to LS7 style heads. Get a nice port match done on the intake and you'll be set.

http://www.mastmotorsports.com/2010/product-view.php?cat=Cylinder%20Heads%20-%20Assembled&id=370

http://www.totalengineairflow.com/products-page/products/cnc-ported-cylinder-heads/gm1/ls1ls21/trick-flow-265cc-gm-ls-cylinder-heads/

Tea 235/245 I have a 427 lsx with tfs245 setup for nitrous. It has an aggressive cam in it but made 570 rwhp locked up in a c6 4l60 car then made 830 on a 300 with soft tune. For dd motor go cathedral you will like it better.

I asked afr about it and they said anything bigger than 245cc was too big for street like I want. I might go with mast, also lme said they can get tfs 245 to flow 360cfms at .600 they wanna charge 4700. Can't T.E.A get similar results? I've heard they are pretty good.

I personally haven't seen a PRC anything that has impressed me to make power.

TEA or Mast simple.

Allpros ls7 retro or the dash-1 head would be a great choice call Richard at w.c.c.h

I personally haven't seen a PRC anything that has impressed me to make power.

I didn't want to be the one to say it.... but yeah I feel the same way.

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 :D

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.

Allpros ls7 retro or the dash-1 head would be a great choice call Richard at w.c.c.h

ohhhhh yaaa now your talking :) all pro wcch !!

I didn't want to be the one to say it.... but yeah I feel the same way.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.

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

http://ls1tech.com/forums/generation-iii-internal-engine/1451321-darth-vader-your-lsx-stroker-ready.html

Thanks,
Tony