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Do Grandad one better and drop a 472 or 500 in it. There is A LOT of aftermarket performance support for that Cadillac engine.

The 390 is pretty easy to get parts for, though.

No, the hydramatic was toast. I used an adapter with a th400. I could find no one willing to touch the hydramatic.

The guys on the Cadillac site think my block may just be too pitted to seal. I actually found a 390 block on Craigslist that is tempting me….. finding a good machine shop really is the issue.

That block is VERY repairable. Drill and tap those corroded holes for a cast iron pipe plug, probably about a 3/8" or 1/2" NPT, screw plugs into the tapped holes with red LocTite, and grind and file them off flush. Then drill a coolant passage back into the plugged spots, using a head gasket as a drilling template.
Jerry

His problem is finding someone with the skill and shop to do it.

I don’t think those holes really matter. You can see the gasket is open between the most corroded parts. I think maybe it’s the pitting closer to the cylinders at issue…

I found a 390 block on Craigslist that seems to be in better shape. If it is bored the same.40 over, can I just move everything over or would I need to replace rings, bearings and all? I’ve never been into the bottom end of an engine before.

It's an easy fix for anyone who can operate a drill motor and a belt sander. As an alternative, I have a complete 390 with zero road miles after a complete rebuild that needs a home.
Jerry

50 shep, send Jerry a PM, talk and see what you can work out. He has what you need all together and in one spot. That motor in that truck with that pedigree, its just cool, really cool and I think worth the effort and expense to get it right. There are just not that many true hot rods like that around any more and you have one!

As for the caddy motor, my father, grandfather and great grandfather were funeral directors. I drove all manner of cadillac sedans, limos, hearses growing up, and all manner of motors, 390, 472, 500, even the lousy 4-6-8 motor with the solonoids on the rockers. What they all had in common was unbelievable torque and power under 3200 rpm. Sometimes lower then that, all in stock form. What fun.

As to the condition of the deck of the block you have, it clearly needs to be machined. Its an old motor, the deck has corroded like every other old motor. I have had decks on 235 blocks that were way worse. But that is why they get machined during the rebuild process. Gets them flat and a fresh sealing face. Same with the heads. That was clearly not done with that motor but unless that block is cracked, I just don't believe it is completly junk.

Thanks for all the encouragement. I did talk to hotrod we live really far apart so it would be a pretty big effort. I actually found a used 365 caddy motor, got it installed today and hoping to fire it up tomorrow and see if it’s any good. That will at least get me up and running and I can continue to mess with this 390.

It looks cool, hopefully will run cool….:).

The Cadillac 365 is one of the smoothest running engines you can get. They're powerful and nearly bullet proof.

Yours looks like a '57 or '58.

As for the 390 deck, it only has to be flat where the head gasket lays, the rest doesn't matter. Solid pipe plugs would be an easy DIY project like Jerry pointed out, all you need is hand tools. Power tools would be quicker, but it could be done without them.