I recently purchased a cadillac 500 motor. I own a 81 chevy 4X4 with a 9 inch lift and 39.5s. I had a sbc 400 (done up) that did not have enough tourque for what i wanted. I'm still in high school so i don't have a whole lot of money to spend on this project. I was wondering if anyone has done this before? I it would be nice to have the 4 speed backing the motor. I have a turbo 400 tranny and a good transfer case if i need to use it. My truck runs on propane so i was thinking about using 472 heads to get the compression up. I have set of headers to go along with it. Those 500 motors have good power so its defenitly what i want. It would be nice to leave those 454s in the dust haha. The only problem is getting the tranny to bolt up and changing the motor mounts i think. If anyone has any ideas or tips it would be much appreciated thanks

Find Davesdeville on here. He's one of the local 500 Cad guys. :) Sounds like a helluva fun project!

Oh yea...and welcome aboard the forums! Good stuff and good people to be found here!

moved here
please post questions in the proper forum for your vehicle.
davesdeville is banned. other members here can help you out.

That was actually a pretty popular swap years ago. I assume people were swapping the tailshaft on the Caddy th400 to a 4WD tailshaft and using the stock transfer case. You could also use a divorced transfer case to eliminate the tailshaft swap. I'm not sure what they do about motor mounts. I would think there would be some articles in cyberspace somewhere (google). You're on the right track though because 39's need lots of torque and Caddy 472/500 = cheap torque.. Have fun dude.

I have a manual and do not recommend it. I think it would be nice with a BOP TH400 with the 4x4 transfer case. The stock Chevy mounting plates can be flipped around backwards and then the caddy mounts will bolt to them. I'm sure a few Caddy places will make a complete swap kit as well. Not sure about leaving any 454's in the dust, lol.

If you're stuck on using the manual then don't forget to engineer a pilot bearing when the engine/crank is out.

this is something im always tempted to do but i probably wont simply because i have too many other projects. actually i m pretty darn sure the 472 heads are actually the same cc as the 500 just the crank is different. u can use 425 heads to do it it seems like u cant but theres directions on how to do it on 500cid.com . the best way thought is to switch pistons if you have a 71-73 motor the pistons have a huge 47 cc dish, if its a 1970 motor u have a little over 10 to 1 compression. u dont know much about running lpg but if u use 74, 472 pistons there completely flat.

they make gearsets that bolt on after a th400 that give u an overdrive a litle pricey but mabey u could save up for it but then u need a new drive shaft too

if u want to use a 4 speed or more because of gas mileage some of us are trying to figure out how to get some of the cylinders to deactivate but don't count on a breakthrough so soon.

I'm doing the same thing with my '70 IH pickup. I have a 500 caddy, 4L80e, and dual transfer cases. I've done a bunch of research, and have concluded that a custom engine crossmember is required.

I have a a 1974 Coupe de Ville with the 472 and a 4L80E in a wrecked '95 2WD 2500 in the back yard. I really want to find out the cheapest way to put the 4L80E in the caddy. I've read the the early 90's diesels had stand alone TCM's, But I haven't found any info on how well this combo works behind a Caddy motor. What fabrication is needed for the sensors? God I want an OD!

mts.com has a swap kit for it - cheap