348 flywheel

[Stumann123]

I've got a 348 truck motor that I've had sitting around for years and I'm finally getting it together to run in a 49 International P/U. It's a stick shift motor that I am putting a 4-speed behind. I had the flywheel resurfaced and when I went to put it back on the engine, I noticed that the bolts holding it to the crank are 7/16" fine thread, but the bole holes in the flywheel are 1/2". Is this the wrong flywheel? The crank does have one pin that lines up with one of the three smaller hoes in the flywheel, but I'm concerned that this isn't enough to take the sheer load. If this is the wrong flywheel, what other ones will fit? Small block, Big block? I originally thought thiswas the original flywheel since I pulled the engine from the truck it came from which was a fairly unmolested truck, but now I'm not so sure.

Thanks in advance...

 

[OldTruckNut]

Stumann, I'm far from an expert on the 348/409 engines, but from everything I've read they use the same flywheel as a small/big block Chevy engine(internal balance). I've never seen a Chevy V8(big block or small) with anything other than 7/16" flywheel bolts, even in the big trucks. On some standard flywheels, the holes did seem a bit large for the bolts, but I don't know if they were 1/2". I think the 292 6cyl may have used 1/2" flywheel bolts with the same hub diameter and bolt circle, maybe that's what your flywheel is for.