Best 350 OEM Block

[carl hinkson]

Originally Posted by Greg Reimer 7376

I got lucky and found a 660 block that caught my attention. That's a '68 large journal 250 or 275 horse 327. This one had the cam tunnel bored directly down the center of the cam boss. The lifters looked to be centerd in their bosses very well, and the casting just had a good visual appearance. I had it sonic tested and the results came back with all 8 cylinder bores very uniform in their thickness, and accurately located .Apparantly the thin wall casting tecniques didn't start until after then. It had to be line honed, and we gave it to Gregg Luneack for a bore hone and deck proceedure, and he asked me where I ever found such a good block. He wished he had it for his super stock car. I put it together, and it's the best 327 we've had yet.
Another unlikely casting I heard about was a 350 with the words HECHO IN MEXICO cast into the rear of the block. Apparently, it wasn't a thin wall block either,because that thing turned out one of the fastest super stock 350's around. The whole thing about building a killer race motor is the block. Good OEM ones are all 40 to 45 years old, so the search isn't getting any easier.

When sonic testing I have found the older blocks worse then the 80's and 90's blocks, There does not seem to be any difference in cylinder wall thickness between the older or newer blocks its just how the cylinder molds were placed during the casting process.

Like I have said I have a lot of blocks that show no core shift but fail a sonic test and some that show a lot of core shift but sonic test fine.

Rather then guess if its OK its always best to sonic and be sure.