[67_C-30]

Originally Posted by monte0185

You are correct in the large journal small jounal specs. I was mearly refrencing the bore and stroke. Anyway. My friend has a 71 vega with a 307 and he runs consistant 11.90's in the 1/4. Now granted its been worked over greatly and is sporting a offenhauser tunnel ram and 2 450 holleys that took us forever to dial in but its been running those same times for nearly 10 years. All we have ever done is a tweek hear and there. I am only saying this cause i dont know of too many other built engines that have held together as long which to me goes to show its durability as well. Not that i wouldnt chunk my 307 out the window for a nicely built 406 in a heartbeat!

I was just clarifying. I only made the reference because I've seen several people over the years go out and buy engines that they couldn't use because of what they heard. It was nothing against you. A lot of people with little engine building experience don't know all the little nuisances and get themselves in trouble sometimes! I know a guy that went out and bought a 3970010 4" bore block and bought a 283 because he wanted to build a 302. He brought them to me to build, and told him they wouldn't interchange. He argued saying that he looked on Mortec and the 3970010 was used for 302/327/350's and he was told "all a 302 is a 327 block with 283 crank". He didn't know about the difference in journal sizes. Another example is "305 and 350 cranks are the same". It is true that they have the same stroke and will interchange. I'm sure you could swap them out and they'd even live in a daily driver, but they won't in high performance engines because of balancing. We put a 305 crank with 350 pistons and rods on the balancing machine one time to see, and it was way off for a high rpm engine.