LFZ

Horsepower is in the heads...so i'm looking for heads for a 383 bottom end, cast crank and forged rods, hyperE pistons, XE274 cam. Its either aluminum AFR 195cc with 74cc combustion chambers, or the aluminum Fastburn heads with 62cc chambers...which head will give me the most flow and the most horsepower. Thank for the help

MotorHead

I would go with the AFR's probably flow better, check thier website, flow numbers I have found are slightly ( this is based on the 210 race ready heads and what a forum members actually got when he bought a set and had them flowed ) on the optomistic side but I would still say they are the better head. Make sure you match the pistons for the chamber size

problemenko

Motorhead, I'm considering a 406 since I've all but ruled out a BB. With your 11:1 compression ratio do you have any problems with pump gas? Also what's your HP estimate?

comp

AFR's

Fevre

I would think the AFR's would give you a wider selection of intake and headers.

mountainmotor

My memory ain't what it used to be but the exhaust flow on the Fast Burns is kinda on the low side ... correct ? Corvette exhaust system hinders things a bit correct ? Pick the best intake to exhaust flow ratio for Corvette , correct ?

Why that XE274 camshaft is the mainest question . Mainest , I like that word

EDIT :

Is the Comp Cams Master Lobe list online ? I don't purchase whats offered generally , I have made what I need in an effort to perfect

LFZ

Because i want to stay with a Hydraulic Flat Tappet cam. Mainly street driving, and hitting the 1/8th mile track a few times next summer.
Edit: going with Cast crank and forged rods.

mountainmotor

I am not being a smartarse , it's obvious you wanted a hydraulic . Did you pick this cam because it is the best choice for your rear gear , trans and converter if it's automatic and lastly ...... heads that you do not have yet ?

See why I asked ? A total package .

LFZ

Mountainmotor....sorry, I didn't mean to sound like a smartarse in my answer. But to answer you in full, yes to all of your above statements... this is my cam of choice as of right now due to the power range, and 110 lobe separation to give somewhat of a lumpy idle...still pondering if a roller cam is really worth the extra expense... I guess I could always change it if better heads require a better cam....what would your advice be?

ppinto1

Redshark6974,

I've been running the FB's on a 350 for about 4 years now, and also have a hydraulic roller cam (the H.O.T. LT4 cam). I can't comment on the AFR's because I have no experience.

Flow numbers are important. But, it pays to look at velocity and combustion chamber shape, also. I'm not sure if the AFR's have a fast burn (heart-like shaped) chamber, but the FB's obviously do. Heads with a combustion chamber like this can usually tolerate more compression while requiring less ignition advance.

I was worried with the intake velocity with I chose these heads - because the 215cc runners are a bit big for my application (350ci instead of 383, etc., 3.55 rear). But, with long headers, I was pleasantly surprised at how this combo pulled at low RPM's - and at 3500 or so, it just takes off.

I guess I chose the FB's - more than any other reason - because they were used on the ZZ430, and I wanted similar output and a reliable configuration. Again, I have no experience with the AFR's - so I can't say if they'd be reliable or not. They certainly have a good reputation, though.

I, too, have a cast crank. It's supposed to be a little better because it's "nodular iron with rolled fillet something or other". In reality, I'm not sure it's any stronger than a run of the mill cast crank. But, I've been shifting at 6500 RPM, and nothing bad has happened yet.....

And, you may want to think about converting your engine to use a hydraulic roller cam. This is my first, and I have to say I'm really pleased with the benefits. In my opinion, I have a healthy cam. And, with a Holley 750 - I can idle at 850RPM and get about 15 inches of vaccum. All the accessories work, and there's a bit of lope in the idle. I don't think you'd be able to get an idle that good with duration that large any other way (outside of increasing displacement, with all other things being equal).

Last thing about the AFR's - Fevre mentioned that you'd have a larger selection of intakes and headers. This is so true, it's painful..... Especially when converting to EFI, there's not too much stuff out there for Vortec-style heads - even now. And, it's not easy to find a D-Port header for a C3. I think the only two companies that have them are Headman and Sanderson.......

EricU

I have a FastBurn 385 in my 69. I am currently using a set of Hooker super comps and have no problem. I am switching to a set of side exit headers with a new set of factory style exhaust covers.

I also have a EFI intake, that came in a C-950 kit (which I have not installed yet). I also have an Eddelbrock 2913 Victor single plane that I was going to convert to EFI.

There's not as many choices for the FastBurns, but there are some!


I have heard that Holley was working on a FastBurn/Vortec style Stealth Ram, but I have not seen one yet.
http://www.holley.com/HiOctn/ProdLin...MS/SR/SR.html]

I really like the FastBurn in my 69, though soon after I installed it, I was wanting more power. But then who doesn't?!!!

Eric.

VETDRMS

I have the AFR195's on my 406 (which pulls to 7000rpm) and I like them. See Sig.



EDIT: Yes, the AFR heads have the "kidney-bean" shaped chambers.

I run 10.7:1 compression on 91 octane with 36-38 degrees total and initial advance (locked out) without any pinging.

checklst

WOW!!!!! It's nice to have such a choice between 2 vary good heads.

The difference between the 2 appears to be a wash, the AFR's might flow slightly better giving a few more ponies but the FAST Burns smaller chamber 62cc will raise the compression and squeeze a couple extra pony’s also.

In this case flip a coin and ENJOY THE PERFORMANCE.

Clink69

I prefer Canfields 195s...

turtlevette

we have so many damn Mopar fans here i'm surprised they aren't all taking a die grinder and hogging them out into a hemi shape.

We need to remember that flow numbers aren't the only critera to be concerned about, unless of course your only wish is that your car scoot down the 1/4 as fast as possible.

I went with the used L98 heads off ebay for 300 bucks. Spend a weekend porting these out and they will produce as much power as the Vortecs with 50lbs less weight, plus they have screw in studs and guideplates. Chev hi performance did a test to prove it. Vortecs are the same design as the fast burn but with smaller valves, pressed in studs and are limited in total valve lift.

I don't get what these high end heads are gonna get you unless again you want a race motor with no low end torque. No fun to drive on the street when you got to rev it to 3000 rpm just to get it to move. But i guess the aftermarket companies love you for donating large amounts of money to their coffers.

VETDRMS

turtlevette I'm no Mopar fan...

Is there anything wrong with wanting one's car to "scoot" fast in 1/4 mile? :P

As far as no low end torque and a lack of driveability, I have to completely disagree with you. My 406, albiet VERY loud (read: bullet mufflers exiting under car) is completely driveable, EVEN with a 4000rpm stall. And contrary to the common belief that you'll constantly be "riding" the converter and needing to rev it high to make it move is a load of #(*@. A torque converter stalls based on the amount of torque applied. Normal driving actually applies very little torque (read, limited slip). So that said, even with the high stall its easy to get around town in. However, that slip does add heat and drop MPG.
Driveability test: My 5'3" 108lb g/f can drive the car around town without issue (even with manual steering! and wide low profile tires).

UKPaul

Can I ask why you're considering 74cc chambers with the AFR heads & not something smaller eg 68cc??

LFZ

Not sure exactly...it was recommended to me. I will consider any alternative to head size and cams from the guys here....thats why i always ask.

C3 Stroker

The AFR's outflow ALL other heads I've seen tested in the 180-200cc range and will definitely yield the most horsepower. They really torque well with cams like yours without a lot of duration. My 383 ('69 coupe) has AFR 195's, competition ported & valve job with titanium retainers: Comp Cams 286HR hydraulic roller cam: Edelbrock 800cfm carb, & RPM Air Gap manifold. With Hooker Super Comp headers & 4:10 gears it runs 11.8 in the 1/4 mile. Check out AFR's website & give them a call. Though not advertised in their catalog, 195cc heads ARE available with 64cc chambers (mine are 64cc); they will gladly size them to your specs.

UKPaul

Thanks for the reply. I asked because I've got a set of AFR180's on order with 68cc chambers (the alternative was 74(76?)cc) & thought maybe I'd missed something when you said you were going for 74cc chambers (most people seem to get the 68cc ones, or get them milled to 64cc). I was told that milling to 64cc would be just below a couple of hundred bucks, so didn't think 200 quid (by the time they get here) was worth it for raising the CR slightly up from approx 9.1:1 that the 68cc chambers will give me (I'll bump the CR up when I chuck some decent pistons in there at a later date).
With ally heads you should really consider bumping the CR up nearer to the limit as you'll get more power (the exhaust note also sounds gorgeous on a high CR V8 ). I haven't a clue what the ideal would be for your engine (cam design & dynamic CR, etc), but there's bound to be somebody here who'd know. The reason I'm only going to 9.1:1 is that I can't afford to touch the bottom end, so hopefully AFR180's & 9.1:1 will give me more power, but won't over stress the bottom end (he hopes!). I figure that if it can't handle running at 9.1:1 then it's gonna blow at some point anyway So, ignore my CR as it's chosen from an economics point of view, if I had the cash I'd go for nearer 10:1 & beef up the bottom end.
In answer to your original question, I'd guess that the fastburn heads would give the most power, simply because of the small chamber volume (much better CR than 74cc would give). I don't know the flow numbers for them, but if they're decent then they'll probably give better power than a better flowing head running a much lower CR. I'd go for the AFR's, but with a smaller chamber, as they flow so well. I really hope that's sound advice because I've just spent a shed load of money on a set!