Posted by Jim Glover (IP: 204.215.203.224) on May 23, 2000 at 17:05:31:
In Reply to: 302/289 trick posted by Scoopy on May 23, 2000 at 14:46:50:
: I'm rebuilding a Falcon for a friend that doesn't have much money, can you explain a little bit more that FAMOS 302/289 trick ( conrods ) & in such case what kind of camshaft would you suggest for that 302 with 289 conrods ,the car has a 4s Manual transmision 8" rear end & he already bought a Weiand Excelerator intake manifold, a holley performer 600 & some headers ?
: Thnks
OK! One more time. First off 289 connecting rods are 5.155 long center to center and 302 rods are 5.090 center to center. Using the block of your choice and a 302 crank with a 289 connecting rod will get you a long-rod 302 inch motor,which makes more power because the piston hesitates at TDC longer to build more cylinder pressure. This will make the piston stick up out of the block about .060 inches, so you will have to machine down the pistons to acheive a zero deck(flush).
Now the suggestion is to use a forged piston and all stock designed pistons(Ford,TRW,etc) have more than enough thickness and strength to allow you to do this and you will have a lighter piston as well(faster revving engine). Stock 289 connecting rods are plenty strong enough for most street and some strip applications, if they are properly reconditioned and quality(read racing type) rod bolts are installed(such as ARP brand).In all my years of experience, I've seldom seen an engine failure due to a smallblock Ford connecting rod. Most failures are related to cylinder block failure due to main bearing cap movement(a good case for a main cap girdle). My engine bored .030 with an .039 thick head gasket and a 54cc combustion chamber has about 10.5 to one compression.
Use a reputable machine shop and you should be alright.