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Well, I don't really have a question. A counseling session maybe.... I've pretty much finished a frame off and now my 1950 sits with an empty engine bay. It came with a 390 Cadillac engine that my grandfather had originally installed in the late 60's. For nostalgic purposes I really wanted to keep the Cadillac motor but man I have had a real hard time finding reliable machine shops and parts are really getting hard to find with these early Cadillac motors. The motor had two cracked heads so I spent a long time trying locate those, finally got the motor installed and running but I'm still getting exhaust gasses into the radiator so now I'm wondering if the block may actually have a crack. The first machine shop said the block was good but he is out of business now..... so.... I've sunk a lot of money into this caddy motor but I'm really starting to think of just going with a belly button motor and going on my merry way..... Anyone in the southern California area that knows a builder that specializes in old caddy motors? I've googled and googled and haven't come up with much....

You need to go talk to the guys at the CLC forum. It's the Cadillac and LaSalle Club of America. They help Cadillac people like Stovebolt helps Chevy truck people.

Which 390 is it? Is it the "good" one with the 331/365/390 geometry? Or is it the pre 429 version?

https://www.cadillaclasalleclub.org/page/forum

The guys on the Modified Cadillac forum might be able to help as well. The Modified chapter is a part of the CLC.

http://www.modifiedcadillac.org/

There is also a performance shop called MTS that builds vintage Cadillac engines.

It’s the good the one, 1960. I have been on that site, it’s how I located my heads. Their best guess was a cracked block.

Rats!

Maybe you'll be able to find another 390.

Salvage all accessories and parts from motor and sell them on Ebay or to that forum. Throw the rest away and install a SBC or BBC. Stuck with this predicament in 2023, your Grand Father would do the same. You have given a gallant try. Time to get it on the road. Stay away from Buick, Pontiac, Cad, Olds old motors. No parts. Too heavy. Too hybrid. Chevy Chevy Chevy. After about 1962, Every trans fits every motor. More HiPo available.
Stop fighting this. Turn sad to happy.

Ha! You’re probably right. Was just hoping to do something a bit different. I’m kind of a “send good money after bad” kind of guy….

Check your PM's.
Jerry

Look at it as a challange which is part of the fun. If you are so inclined, take the motor apart. Should not take you more then half a day. Take photos and keep the parts organized. Get it down to a bare block. Get the block to a reasonably decent machine shop, tell them what is going on and have them throughly mag the block. If the block is painted, they may want to shot clean it just to get the paint off and do a through job of magging it. If it passes mag, and it might, have them check the decks and make sure they are flat. If not, have them cut a bit and put the motor back together.

A caddy motor of all things. How cool!

Ya, and a '60 390 is rated at 325 hp. It'll launch a 5000 lb Cadillac without breaking a sweat. It should make a lightweight '50 Chevy truck fly!

I assume its hooked up to the the Hydramatic?

X2.

A Caddy motor in an old truck, that was modded that way 60 years ago by your grandfather….is a novelty worth recreating.

It will be the opposite of convenient or easy. But the result will be worth the pain, IMO.

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.

The 365 is a 58. The 390 sounded great but it kept blowing the radiator hoses off. If it wasn’t for that you wouldn’t even known it was getting combustion gasses into the radiator.

Just by looking at the deck though even as pitted as it is I can’t tell where the leakage would be coming from since the areas around the cylinders seem ok. Which still makes be suspicious of the block itself…. I really need to ask around and find a solid machine shop. I’m learning that a bad one can cost you a lot of money and wasted time.

True about machine shops.

I'm guessing it was going through the headgasket - probably from warpage/wear on the deck and/or head

Now *this* is a cool story! Thanks all for helping the OP out! This is what its all about!

You all made my day. Brought me in from the ledge, even.

50Shep -- I hope you can make Grandpa's mod work! Good on ya!!



John

Back in the day when we found a block or a head that was pitted we used an epoxy filler. It's been so long ago now I don't recall the name of it. We would use a hand held bead blaster and a soda (baking) blaster to clean out the pits. Grind out some of the bad ones with some small stones. Even drill some small holes for the epoxy to grip to. Apply the epoxy to the pitted areas and let it cure. Then file it flat. Apply a little more if there were imperfections. When the head gasket and head are bolted on it would hold the epoxy in place and made for a good seal. Just an option to salvage an old irreplaceable engine.

Devcon Epoxy Steel- - - - -it can even be drilled and tapped in some applications. It's also possible to machine the top of the block for a stainless steel O ring made from .032" diameter aircraft safety wire, which is usually used with a solid copper head gasket for blower-equipped tractor pull engines. I've done that on several MOPAR hemi engines for a friend's unlimited class pull truck.
Jerry

After 4 years and tons of help from this site grandpas truck went for its maiden voyage down the street. The 365 caddy motor seems to be in good shape. Fun fact, don’t ever fire up an engine without the carburetor on. I got to try out my fire extinguisher this weekend. Not too much damage done but I’ll need to replace a few wires.

Oh, and I’m going to get a t-shirt made that says “argh, I knew I should have replaced the rear main seal….drip drip”

My 365 has been leaking from the rear main seal for 21 years. I should have named the car Exxon Valdez instead of Bismarck.

They always leak.

Nevertheless, it beats a Chevy 350 by a long shot.

Wow! Great news and beautiful truck.

What a fantastic ending to a "Sad Story" at the start!

Very glad you stuck it out and were able to get Grandpa's truck back on the road.

Thanks for sharing your beautiful truck on it's "maiden voyage".

Does anybody else remember the Allard sports car- - - -the one with the Cadillac V8 for a powerplant? I've got an Excalibur roadster kit car waiting in a long line of projects- - - - -Dad's old 390 just might find a new home after all!

insider.hagerty.com/car/1952-allard-j2/

Jerry

That would be unique for sure!

Jerry,

I remember the Allards!

Ed

Ed, I'd been planning to install any of several Chevy based engines in the old Excalibur, from a Mercruiser 4 cylinder to a 230 six, and a few different small block V8's, and hadn't even considered using the Cad engine. However, with a little adapting I can still run the same powertrain- - - -a 4L60 transmission and a Toyota Supra independent rear suspension with a frame-mounted differential, and put the engine Dad spent lots of time building and dyno testing to good use. He's been gone since 2014, just over a month shy of his 90th. birthday. The 4L60 has a Chevy bell housing, but mating the Caddy to it shouldn't be much of a chore.
Jerry

Man, I wish I lived closer to you. You have some cool project ideas. I lost my Dad when he was 61, I don't imagine its any easier at 90. My Dad wasn't into cars at all but he was an electrical engineer and he was always willing to help me solve problems. The second he had enough money to afford a car he didn't have to work on he was happy as could be and he hated grease on his tools. I remember arguing with him as a teenager when he told me to take all of the tools back out and wipe them down. Now I chuckle when I wipe down my tools. Speedgems makes a Caddy to Chevy trans adapter. It was pricey but came with all necessary components (flywheel, nice chrome starter and all the bolts). I have and extra 390 now as well, though the deck obviously needs some love.... I was thinking of a 64 Lemans GTO clone with a Cadillac 390...