I am installing a GM 350/ TH 400 into my 60 Cad soon and am wondering if anybody out there has done the operation. I need info on anyone who manufactures conversion mounts and such. Any help would be appreciated. Thanks
Not aware of any conversion mounts. Whats wrong w/ the 390? There is nothing worse than seeing a beautiful caddy with a boring ol small block chevy under the hood. I'm not a purist by anymeans, but a cadillac should have a cadillac in it.... hell even if it is a later model 500. Just my $.02
You're NOT gonna like your MPG'S after all the f%&kin' around (HEAVY car, small motor). That's why Cads always came with big motors. You'd better start measuring junk yard axles for something that's close to your Cad's axle width- nothing else will be that wide, and gear availability to swap out what's in your current axle will be NADA... Rebuild your 390- you'll like it alot more when you're through... -Betruger-
I was thinking a Cad motor would be easier to install, even if you went from the dual-coupling 4-speed Hydro to a TH400 3-speed. You'd need a short tail trans, for sure. A 350 would probably move it around, it works in my 5000-lb Suburban, but I liked driving my old Pontiac a lot better, same trans as in that Caddy and a 389 and it would get up and go when I wanted.
i had a olds 260 in my 61 no problem not fast but moved car easly and it was 2bbl with 3speed metric trans, all of it came from 78 cutl***. center.level motor, fab brakets to motor mounts! rigid is ok to just be sure if motor is soild mount ****** is too. youl have to have front shaft re done and the carrier bearing rubber support is not get able i had to make one.
The 390 in the car has been sitting for 35 years and I can't get it to turn. I've tried marvel mystery oil, ATF, removing the starter, and all the other tricks but haven't had any luck with it. It will cost around 1200 for a rebuild kit, not to mention having the machine work done on the engine. I also have an extra 472/ 400 Cadillac drive train , but the cost of re- building one of those is almost as expensive as the 390. The 350 that I have is set up to produce about 400 horses and should move this car pretty well. I'm thinking that the issues I'm facing are with the motor mounts, transmission mounts/ cross member ( Cadillac ****** mounts are near the front of the bellhousing) , and fitting the Gm yoke to the big cadillac driveshaft. Keep your ideas coming !
Trying to put a lat(er) Caddy mill in that is difficult, also. With the '63 390 and the 425,472 and 500ci, they moved the sump and it will not clear the crossmember. A friend of mine tried this in his '59 and ended up subframing it with the later Caddy frame
There are some of these motors with a rear sump, though, aren't there? Really late ones if I remember right, only in certain models.
I HAV E A 350/ 400 COMBO IN MY 62 NO BIG PROBLEM GETS 18MPG FLOODING, SOUND BETTER THAT WAY. NEED YOKE FROM 4WD TRUCK LONGER USE SAME DRIVE SHAFT, TOOK STOCK REAR TRANS MOUNT AND MODIFIED, and used dirt track motor mounts, welded small square and used rubber cup mounts, still working out some vibrations at 70-80mph. use exhaust manifolds of 78m/c with dipstick in pan use oil pan also. will try to take some pics. if you want have driving to florida, nashville, pegion forge, about 10k miles so far. did swap because had ristpin slap in 390 and 350 was won at a car show. its just a stock 350 pulls great and cruises great. thanks jimmy p.
Horsepower isn't the measurement to make for a car that big...it's torque. The 350 will do the job, just not as well as a motor with more torque. I did the conversion in my 60 Cad, went to a 472/400 set-up. The rear sump and pan had to be sourced out of a Cad performance shop. Extra capacity added to the pan too. The crossmember had to be modified too. Kiwi Kev helped a great deal, made me some block hugger headers. At the time, nobody offered block huggers for those motors that had rear dump exhaust. I think that since then Sanderson came out with some. My 390 was on it's second full rebuild, with poor success, the first one spun a crank bearing, the second didn't come out any better. And when the 390 was a runner, I kept a rebuilt water pump in the trunk at all times...and needed it! I love the way those motors look, when they run, they run great. The motor swap was the cheaper alternative for me. By the way, I got rid of the split driveshaft and raised the hump in the floor for lowering capability as well.
I put a rebuilt 425 out of a ('78 C.D.V. i.i.r.c.) into a '70 that had a 472 - after realizing about 8 mpg ( due to less engine displacement) and no way to change the gear in the axle, I sold it to the first 'boon that came along and had to have it. That was 14 yrs. ago now... -Betruger-
Caddy-O Did you ever find a conversion mount? I have a 1953 Coupe deville and I am in the same boat as you. My 331 engine went out on me and will cost just as much to rebuild it. I want to put in a 350 to get it on the road again. Please let me know what information you found on this project. Thanks, Steve O.
Sorry no Pix..I sold the car a few years ago. I did install the 350/400 and was very happy with the swap. Equaled worry free long distance driving without the worry of finding 390 and hydamatic parts out in the middle of nowhere. - NASCAR type solid mounts (Use existing frame holes) - Ch***is Engineering rubber mounts - Remove front ****** cradle mount (2 mounts on a Cadillac - front and rear; Remove front) - Lokar column shift kit - weld tab onto rear Cadillac trans mount to accept GM trans - Exhaust dumps over steering box. Tight fit...so make sure you know a good exhaust installer
I know it's not helpful, but I just threw up in my mouth a little. but I got a thing for caddy mills. been driving the snot out of a 390 for 10 years now. started with a 4 speed, and now at-5
I know this is an old thread, but to help anyone trying to swap a 472/500, use an Eldorado oil pan to get the rear sump. Make sure to grab the oil pickup also with the pan.
The Jalopy Journal
