Ford Repair: performance on 347ci, aditional info, mustang fastback

Question
HI Steve..
thanks for your advice, but could ilustrade me more about why does some kit have to be balance... what do they mean for that, I was thinking that it is for balance the pistons and I beams? thanks very much Steve
Rodrigo H
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Followup To
Question -
Hi Steve
I have a 1974 302ci that is going to be in a 67 mustang fastback,I already bought from you the Performer RPM from edelbrock: aluminum cilinder heads(EDL-60229), Rolloer rocker(CRN-11746-16), Camshaft and lifters(EDL-7122), Timming chain and gears(EDL-7820), Push Rods(9632), gaskets and hardware.
WELL the question is that what is the best parts for building to be a stroker 347ci, and if it is a good idea to make this convertion, the idea is to have a good legal street performance classic car, if you any aditional info of the stroker engine I will apreciate very much
thanks a lot
Rodrigo H

Answer -
Rodrigo-

  Sure, I think the switch to a stroker motor is a good way to go.  As for parts, I'd go with a kit from a company like D.S.S. or Coast High Performance.  For a street legal motor with parts like you've listed you won't need anything fancy.  A cast stroker crank will work fine and I-beam rods should be ok.  I would, however, definitely advise you to go with a kit that has forged pistons.  Hypereutectic pistons simply just aren't good for performance applications.  I've been using a D.S.S. 331 stroker kit for almost 2 years and I've been very pleased with it's performance and was impressed with it's quality of parts.  A 331 and 347 will bump up the power almost the same (although the 331 will make a tad less power), but a 331 will reduce stress on the pistons unless the 347 kit is designed very well.  I'd say with the parts you listed, a 347 should make somewhere between 325-375hp...depending on the intake/induction setup.  Hope this helps.

Steve

Answer
Rodrigo-

  Balancing is usually needed when parts aren't specifically chosen to go together.  For instance, when you use an aftermarket crank and polished stock rods. Balancing is done by adding a heavy metal (usually tungsten) to key places in the assembly (usually on the crank) to keep vibrations to a minimum.  Harmonic vibrations caused by rotation are kept in check by the harmonic balancer, but sometimes it's necessary to help the balancer out by balancing the internal assembly as well.  Hope this helps.

Steve