79cam

im buying a nice set of heads and i dont know which ones will be better a 195cc 190cc 185cc or 180cc intake runners; which would create the most power(all have 64cc 2.05 and 1.6). im building a 427c.i. sbc with a set of 76mm turbos, custom ground cam, 9:1 comp. th400 1000hp rated w/a trans brake w/2.73 and a mini spool ect... also any ideas on what blow thru carb i should use (ALL my motor parts are coming from PBM) -thanks for the help-

DIGGLER

iTrader: (1)

None of those. 220cc+.

superirocz

iTrader: (5)

Diggler is correct 220 or better. With over 400ci and a pair of 76s you need some big heads. I have a pair of 235 alumunuim heads I ran on my 406 that have about 300 miles on them and 8 passes and my car went a 9.7@148 with them.

$900 for them I can get you the specs if your interested.

Doom86

+220 easy

I wouldn't put 195's on a 400ci for anything but a dump truck.

Pro-Filer are probably the best head for the money you will find but I don't think they have over 210cc IIRC.

Spieir Racing Heads just released awesome looking new line with 2.5 and 2.72 minimum cross sectional area's. The finished volumes on the 2.5's are 227cc and not sure on the other.

daverr

iTrader: (1)

18* or 15* cylinderheads or sb2.2 . forget carbs go EFI.

79cam

wow thanks, the people ive been talking to said 195cc yet none of them have a turbo motor, but the 220+ sounds better. ill look into thos heads (doom) thanks for the tips

Orr89RocZ

iTrader: (20)

I have 195's on my twin turbo 400. Abit small yes, but I dont turn alot of rpm...dont need to with turbo motors. Doing it all over again, I would have went with 210s with 2.08 valve but I used what I had left over from my 383 nitrous motor and its been plenty. I have the power to go low 9's if I had a transbrake and I havent touched race gas yet or meth injection.

If you plan on turning somewhere near 6500+ rpm shift based on the cam's duration of 260 deg (that at .050 right?) from your other thread, a good 220cc head would work well. YOu could easily go 230-235cc heads. Really need a large cross section not necessarily large cc's. 210's could work ok and be a minimal starting point. I seen guys make well over 1300hp with 210s on 383-400" motors.

427's need alot of air. 76's on that motor will want to push 1000+ hp easily and will be very happy operating there. You will have 8 second power, let alone getting into the 9's unless you live at high altitude.

always tinkerin

iTrader: (1)

X2

AFR 227's pushrod pinch (mcsa) is close to 2.3" which would be a decent match for 400ci. and 6000+

Matching MCSA to cubic inches/RPM is the best way to pick heads IMHO!

Orr89RocZ

iTrader: (20)

227's are great heads but may require special 60/40 pistons and special offset rockers or lifters. AFR's 220's are a bolt on regular 23 deg head that will also compete well with the 227. Any of those larger heads would fit a 427.

RoadHammer

What about AFR's new 235cc heads for the SBC. They are still 23 degree and flow damn close to 18 degree heads.

Doom86

Close to 2.3 really isn't enough for a 427ci like this. They move a lot of volume. That ~2.3sq/in port can flow all it wants when the port speed gets too high the port gets smaller and smaller the higher you spin it because of turbulence on the surface.

Having just too little of a head is worse then having just to big. People often confuse the "heads of old" when thinking this through. The stuff today is highly efficient and a good flowing "large head" can keep the port speed up.

I would like to know the true volume of that AFR head if it has that narrow a MCSA and 227 advertised volume.

Orr89RocZ what 227 head are you saying is 60/40?

There are a lot of great heads on the market if you are serious and are investing a lot of money I would talk to someone who builds heads for trophy winners. Their heads don't cost anymore then off the shelf magazine spank heads and will be built for your application.

superirocz

iTrader: (5)

I will be going with a set of dart cnc 227 heads. I was looking at the new AFR 235 heads and after talking with my builder he thinks the darts have the best deck and said the new 235 AFR are nice but a little thin on the castings for large boost. Talk to a reputable builder and build the heads to fit your needs.

If all you want is 1000 flywheel hp any alloy heads will do the job for about $1200 a set new.

Doom86

Those are no joke they sing like a choir girl when done up right. Ported Dart 220 are popular in racing for a reason and it's not because of their sales gimmicks and advertising power. Those same heads ported can and do make 700hp on 350ci SBC, they are very popular in 23' rule circle track racing.

I wouldn't even consider AFR for a high end build like this, let them be used what they are made for, powering "cruisers", and winning flow bench races. Brodix, Dart, Pro-filer, much better choices and designed for port speed not flow.

The thing I really like about Spieir Racing Heads is what other company has full disclosure about their product right on their web page? You can see the port speed at the opening, PRP, short turn, throat, REAL volume, cross section at PRP, thoat, ect. That is awesome IMO it shows they want educated customers.

Orr89RocZ

iTrader: (20)

Thats not true. Guys are using those heads with great success, even out the box. The guy with the twin 76mm turbo 406 on turboforums switched to these heads and runs mid lower 8's at almost 170mph. Thats a good bit of boost...over 25psi from my calcs. How much more do you want/need? The deck is more than fine for bigger boost levels. Darts heads are better for applications where you have someone special port the heads to fit the application. Out the box they are ok but require work to be great. AFR's are more bolt on performance oriented and do well for what they are. For a street/strip application on boost, I see no reason to worry about special porting of heads...you will make power


And Doom, I was talking about the AFR 227 and 235 heads, they do require some special parts. The valve spacing is 60/40 and those can be used on some regular 23 deg pistons but really need to watch piston to valve clearance. I am not sure if the DARTs are the same or if they are a regular head.

AFR 227's cc out closer to 218cc from what I read. Not sure of the CSA but they seem to be large enough to feed a 400 inch motor to 7K rpm. That should feed a twin turbo 427.

superirocz

iTrader: (5)

I'm not saying they don't work and with good sucess but I have been told by several of the best sbc builders in the country the AFR can have issues with castings at high levels 1300hp and up. Andy Jensen who has a sbc 427 corvette with a 106 turbo has gone over 230mph in the 1/4 and has been doing that for almost 10 years now. Andy is one of the best and has been building some sick SBCs for a long time and he prefers brodix or Dart. Again not saying they are junk I just want a motor that will live a long life with minimuim problems and I'm shooting for 1500+ hp and in a heavy street car.

For this guys purposes I don't think he anything to wory about with any head but we know how it snow ***** and all the sudden 1000hp just isn't enough anymore

Doom86

You don't need to port Dart heads to make them run hard, put the AFR sales brochure down and step back slowly! No sudden movement!



Simply having results doesn't mean it was the best possible solution. They all go forward when you press the pedal.

Orr89RocZ

iTrader: (20)

I am not turning this into a head debate, but I can show you examples of out the box AFR heads beating ported version of other heads in HP produced on the dyno. Not sales brochures...I have my position on the aftermarket heads...some work better than others in certain combos. For the best results, custom ported heads with custom cam to match beats off the shelf jobs. Its all how you want to spend your money. Out the box darts will work but unless they are the fully CNC'd versions, the ports can use a good cleanup

RoadHammer

Doesn't Andy Jensen run those crazy CFE SBX Billet heads on that 427?

superirocz

iTrader: (5)

Yes he does run those on his turbo vette. That car is a sight to see go down the 1/4. 2500+HP with a sbc 427 and a 106 turbo and a lenco.