Am in the process of building a 73 302 and am thinking of going with flat top pistions and getting a mild cam. What should I get for intake and carb. And what should I do to the heads. Any help would be great.
If you are going with a stock rebuild, I suggest going with an Eldelbrock Performer intake and a 600 cfm vacuum secondary, Holley Carburetor. As far as the heads, are concerned, I wouldn't do any thing to them, unless you know how to port and polish, yourself. The Edelbrock Performer Rpm or Patriot Freedom Series heads, would do great. If you change the heads, go with the Eldelbrock Performer RPM intake Manifold. As far as a cam, I forget the part #, but the Comp. Cams .500 lift with 270* duration, will work Awsome, with that combination.:Handshake
Am going stock except the flat top pistons cam and timing chain. I do know how to port and polish I was going to match all the gaskets but do I need to have smaller cc chamber or larger with the flat tops am trying to get some hp back and get the compression up and am trying to do this all on a budget. Any tricks or tip to get the hp up on a low hp motor would be great. And if anyone has a recipe for a build that would be great. And will gt40p head work on my motor. And what long tube headers fit best and what ones will fit the gt40p heads. Thanks all.
If, you do indeed, know how to port and polish. Go ahead and do so. The intake, carburetor and cam I suggested, will definately, wake your motor up. You will fill the difference, in the seat of your pants. Just, DO NOT go any bigger on the cam, lift or duration, or your engine will get sluggish. You also can't go any more on the duration ,with a stock torque converter. If you go any bigger on duration, you will have trouble at stop lights, keeping it running. You will have to keep giving it a little throttle, or a lot of throttle, to keep it running. It would become a pain to drive, to the point, you would not want to drive it. Trust me, I have been down that road. As far as, the GT40P heads, you would have trouble with the headers, as headers are a problem on our cars, from the beginning. The GT40 heads would be what you need, because of the plug angle. It would be the same as the stock heads.
Port match the intakes. On the exhaust, I'd open up the roof and port sides to match the header gaskets, Also remove the thermactor bump from the port roof. Then bowl blend the area under the vavles. Finish off the job with a performance valve job. Also recommed screw in studs and guide plates if going larger than a Comp 268H. All that considered, buying a fresh set of aftermarket heads would probably be more cost effective after you add up what you'll spend to get a set of 73 heads to the level of even budget aftermarket heads will cost. Intake ? I'd never consider a Performer intake, at least not a new one. An RPM will work just as well down on the bottom, but give you more oompf up top and at least leave you room for improvements later on. And don't just go out and buy the first set of flat tops you find. Flat tops for 302's are not all alike. The pin height varies from 1.585 to 1.620, with a 73 block (or any 302 block really) you want the taller height to get to or closest to a zero deck at TDC. 1.585's + the O.E. deck =numbers for a 302 block will leave the piston well below the deck and yeild far less than 9 to 1 compression. Zero deck flat tops + a 58 cc chamber will get you close to 10 to 1. Zero deck lates you tailor the heads to the block to yeild the comp ratio you desire.
All great info. Budgets are wonderful management tools - until they are blown. So I calculate to the high end and normally break even. I'm a week out from removal, disassembly, bore/stroke/forge on my 302. You may want to consider whomever you are obtaining your rotating assembly from knows what the head cc is to ensure you receive the correct pistons for your compression ratio. Kind of important...
Great point! My thought is if you are dealing with a completely disassembled motor, you may want to consider spending the $$$ and go with a forged rotating assembly. With a solid base, it won't matter what direction you pursue from there, i.e. blown, turbo, N/A. The internals are prepared to to deal with it, and, you won't need to rebuild twice should you change your mind afterwards. I'd avoid cast or hypereutectic - especially if you intend to increase hp later. They are fine for strictly stock application, but I've seen on other forums the results of boost and it is both impressive, and costly.
IMO, with factory ported heads I'd run the xe268. If you were to buy an alloy head (165-175cc intake) go with the xe274. Changing converter size will help slot, 2500rpm will be fine. I'm not sure what your fuels are like but I'd set the comp at no less than 10:1 for the 268 and 10.5:1 for the 274. You need 180-200 cranking psi to get it going good. As for intake, I like using the rpm airgaps and a 650dp. Ignition is another place you get hp and more importantly, reliability. You can't go wrong with an msd set up. Glenn
Forged rotating assemblies are highly over rated, if you're not planning to huff it or add NOS. The stock cranks (except for the 81-85 50 oz 5.0 crank) are very good, tough parts. They're fine to 7500 rpms. As are the stock C8OE & F2TE rods (all SBF rods were forgings) with the stock bolts replaced with ARP's, again, good to 7500 rpms. As for cast and hyper pistons ? They're fine for performance builds where you're not going to huff it or add NOS, Many of Ford's factory performance engines of the 60's had cast pistons (289 Hi-PO, 428 CJ, 429CJ to name a few) Both cast and hypers are also good to 7500 rpms if your not boosting it.
I am fairly certain that there are those who have dealt with the carnage aftermath because they elected to forego the forged route, only to regret it later as it cost them more money, would have an entirely different opinion. I tend to take education in learning from other's mistakes and not repeating them... If, IF he decides to increase his hp in the future, (assuming worst-case scenario), it would be cheaper and less time-consuming now, than buying another, stronger rotating assembly, then. Why pay and rebuild, TWICE?
A lot of the time the non forged engines fail because of poor tune. I would use factory parts for upto 450hp apart from pistons. I have used cast stroker parts upto 550hp without failure but the tunes were correct. If you want more hp later on, build a stroker with forged internals. But for now, on your budget go with the hyper flat tops and mild hid cam. Glenn
