Hi, I'm considering rebuilding the engine in my maverick and I wanted to ask a question or two to help with decisions. First, I'm going to list everything major I have decided on. The engine is a stock 302 currently equipped with an Edelbrock Performer RPM intake manifold and 575 CFM Demon Carburetor. The decided upgrades are as follows: Comp Cams Xtreme Energy camshaft (268/280 duration, 0.509/0.512 lift, 351W firing order) stage 3 clutch and chromoly flywheel combo 347 SCAT based stroker kit (28oz imbalance, forged pistons and rods, cast crankshaft) 1.6 roller rockers 2.055 intake/1.6 exhaust cylinder heads (60 or 64 cc) My main question regards choosing cylinder heads. I'm looking for around 10:1 compression and can obtain it regardless of the cylinder head combustion chamber, but if both 60 cc and 64 cc can give exactly 10:1 just based on the stroker kit, does either have an advantage over the other? if it helps, the 60cc have 210 intake runners and the 64 cc have 200 intake runners. My second question regards appropriate compression ratio. What's the highest compression ratio for premium unleaded pump gas at sea level altitude? Thanks in advance
I'm not understanding the cylinder head question. What kind of heads are they? Aluminum? Iron? You know the valve size so I figure you have a certain head in mind. What will the car be doing most of the time? What kind of RPM will it see? If its' a mostly street car the runner size sounds a little too big for a 347. Go for the smaller ones if you don't see high RPM a lot. Most good (Trick Flow, AFR, Canfield) 180-190 runner heads can support 500+ HP and still be responsive at low RPM. Since you live in CA. like me low 91 octane fuel is the best we can easily get. I figure (And this is just a educated guess) 10:1 compression would be fine with Aluminum heads and you should still be able to run the proper timing advance. With Iron heads I would not go too far over 9:1. or maybe 9.5:1. I am building a 400+ HP 331 with 9.55:1 compression with aluminum heads and hope to be able to run 87 octane with no problems since aluminum sheds heat better. I also see you put a T-5 in yours. Ain't it great? That's just my opinion. Others here definitely have more experience with multiple engine compression combos than I do so hopefully they can help. Good luck. Oh and where in CA do you live? I'm in Fresno.
The 64's will give you slightly less valve shrouding, that's about the only advantage. I'm running my 331 with 10.4 to one on 91 premium now with a Z303 cam and Canfield aluminum heads.
@69GT: I live in Santa Barbara. Both pairs of cylinder heads are aluminum. I'm looking to bring out the full potential of my engine, but keep it streetable. Having 800HP, while possible, is unnecessary and very costly. Something around 450HP and great throttle response along with a lopey sound is what I'm looking for. Honestly, I don't understand what they mean when they specify intake runners. Is it related to porting? By which I know by porting heads you remove metal to reduce restriction and increase flow.
The bigger the runner, the lower the intake charge velocity which is more important for street operation. You're not going to see a whole lot of difference between a 200 and a 210 runner head. Flip a coin and pick a head.
so, if the difference was between a 180 or 210, the 180 would be the better choice? or is that inverted?
I'd go 180. Ok I went 185 with my AFRs. Yeah the 180-200-210 runner refers to volume in CCs. The larger the volume the slower the velocity of the incoming air which will make the motor feel a little doggy down low. Also low velocity on motors running carburetors means possible fuel mixing problems at low RPMs due to fuel droplets falling out of suspension. I usually see runner volumes like that on street Windsor strokers with 393-427 inches and even then with higher RPM power in mind. From what I know your 347 should be easily capable of 450 HP. My 331 is supposed to make 420 or so at 9.55:1 so yours should be pretty mean. The only reason I left my compression in the 9s was so I could run 87 octane gas. And if the mood struck me later I could add a little boost. If you are trying to be street-able and only have the 200 or 210 to choose from I'd do the 200. If you can get 180-190 that would be better. It will mostly affect where your max power will occur. The bigger runners will make your motor want to rev higher before it peaks. You are basically moving everything including your torque peak upwards in the power band. If 6200 RPM is all the motor will see than build it to peak its HP at 6000. Of course there is more to this. Like you want a cam and probably a good dual plane intake manifold like an Air gap or Stealth that is also made to perform in the 2500-6000 RPM range. I am just suggesting these things. But matching all the parts to your desired RPM will do wonders for your cars drivability. Just match the parts and your car will run great. Oh, and what rear gears you run also factor in. A higher RPM motor that peaks its torque higher up will want more rear gear.
Well spoken I don't recall what the runner volume is on the Canfields on my 331, but I've never been dissapointed at the end result. They're the equivalent of AFR 165's though. And combined with the 3x2 and Z303 cam, the powerband starts at 1500 and ends about at 6500. Very streetable, and turns in respectable times in the 1/4.
Yeah baddad457 those Canfields are no joke My friend has a 331 with a set of Canfields and one of those old school Blue Racer roller cams and about 11:1 in his 66 Mustang and the best description under full throttle is OMG! I then yell at him for not getting rid of the stock drum brakes
I found several sets of heads and am now having difficulty selecting which I want, haha. Suggestions? 180cc intake runner, 60cc chambers, 2.02/1.6 valves 200cc intake runner, 64cc chambers, 2.055/1.6 valves
What brand? What price? Beware Craigslist and Ebay sellers of cheap pre-assembled Pro-comp and other knock off heads! My friend picked up a set for $580 and the damn things had 2.05 intake valves in a 2.02 hole. Also had I kid you not, stock 5.0 valve springs. Coil bind at like .500 lift. Massive casting flash and bad port alignment. By the time he got the heads straitened out they cost him more than the AFR 185s I have To be fair. I think the only thing that was Pro comps fault was the slightly off center ports and casting flash. The Ebay seller was probably throwing them together with junk around his shop so he could advertise them as "assembled". My other friend fixed them by porting them and removing the flaws. And of course he had to buy all the (correct) parts to assemble them. I guess I'm saying I'd rather buy used Edlebrocks than "new" Pro-comps or other knock offs from mysterious sellers. Also, It doesn't hurt to do research and ask people who run the type of head you are thinking of buying. That's why I bought AFRs. But close in the running were, Canfield, and TFS. Having a friend of a friend who worked at AFR was the final deciding factor for me. My friend with the fixed up Pro-comps is about a month from firing up his new motor so if I remember I'll let you know how it goes.
it's a company I found on eBay called CGM motorsports. My dad purchased one of their top engine kits for his 88 mustang and has no regrets. they have all sorts of options and stuff, a little tricky to find, though. Have you heard of them?
No. But if they have a lot of positive feedback they probably are alright. You can't get away with selling crap for too long before your name becomes mud on the internet I went to their website and can't find the brand of heads they use. Probably Pro-comp or that other brand. Can't remember. One's from Australia I think the other might be Chinese. They will work alright if assembled properly. I would gasket match them at the very least befor installing them.
they're like 99.2% positive feedback and heads cost about $630 for the pair and are good up to .550 lift, .600 for a slight addition. $1500 for heads, intake, cam. I hope they're not chinese...
You could always ask them what brand the heads are Even if they are Pro-topline or Pro-comp they are probably OK with a little prep work. Keep in mind I am only one opinion. And I am going off what a few other people I know have said. The one big negative was from my good friend who also owns a Maverick. And now after the porting they look fantastic and probably flow great too. I know a guy in San Diego who ports heads for a living and he says they are damn good when he gets done porting them and just mediocre out of the box. If you are on a tight budget they could always be ported later. TFS AFR and Canfield will make significantly more power out of the box according to the head comparisons I've seen. But again if you want them now and only have 600+ dollars you can just gasket match em' and wait to port them later. The power difference on a 331 was near 30-40 HP in favor of the better heads. And I think the cheap aluminum heads made about 30-40 HP more than a set of stock heads on the same motor. So the AFR and TFS heads made 80+ HP over stock and the Pro-comps made 30-40 HP over stock. And of course weigh 50 LBS less
