...on the left side motor mount of a big block 4-speed car? I just want to get the engine in and start driving it, but I'm starting to rethink that one item. I know the car will get 500 miles of rather calm driving. Until the clutch is broken in. Just curious if any of you have had any life out of them?

Do it now while it's easy.

They're cheap at the auto-parts store; I think about $15 at O'Reilly's. Much cheaper than a fan & shroud, or radiator. I'd do the trans mount insulator too.

I would look for a quality mount. Some of the made in China rubber mounts are junk.

The OE hold up pretty well if you don't tromp is very much. The current re-pops seem to have issues. I would (and did) get a Schumacher poly lock mount for the left side. If its a drag application, a torque strap is a really good idea.

I'm thinking a torque strap is going to be a must. I'll probably go with the Poly-locks when I get the new engine done. I really would rather replace the mount than the radiator.

I'd like to find a Chinese made mount. All I've found lately are those made in India. They aren't made out of rubber, I think it's elephant dung. If they're made in Korea they are probably ok.

BUT, no matter where they are made use a torque strap.

Jim,
Actually, they are made in Korea. I can't remember what brand they are. I guess I will see before too long how well they hold up.