Cadillac 8.2 Liter into G body

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as the title says

Im wondering just what would be involved in the swap,

( for people who don't know, its an 86 grand prix with a stock 305 sbc)

it wouldnt be hard for me to find an old 1970 eldorado or something and haul the engine out, im just wondering if it would fit right into place, what transmission would be good, etc etc

work done at home lol

thanks in advance:thumbs:

posted by  nighthawk

Did I read the title wrong? Did you say 8.2-litre?.....:drool:

posted by  Cliffy

Yeah, 500in³ lol...400 hp (298 kW) and 550 ft·lb (746 N·m) of torque :hi:.

posted by  chris_knows

add cam, headers, heads and carb for around 7-750 :hi:

but the best part is that these motors are cheap as hell too

posted by  nighthawk

i read of someone doing this on another forum, if i see them, ill ask some questions. couple things off the top of my head, i imagine you would prob have to use the stock 400 turbo caddy transmission so you would have to realign the crossmember and prob shorten the driveshaft as well as change the yoke. you might run into steering clearance issues. alot of weight on the front end as well. you would have to fit a 4 core radiator in, i dunno if you would have problems getting the motor mounts to line up, might have to build them up a little too. also would the headers be bumping into the upper a arms?

i had a smooth running 500 or 472 (cant remeber what it was) i would have given ya about 4 years ago....
http://pic15.picturetrail.com/VOL628/2683405/13863349/256290742.jpg

but shes in china now:thumbs:

posted by  adamc44

thanks for the info, I kind of overlooked most of the things you said lol

do you know of any really large engines that would go in my car slightly easier ?

posted by  nighthawk

small block chevy 400, 350, 355, 383

i could be wrong on some of that stuff, but thats just a few things to think about.


i think like the grand prix, montes, and others all have the same frames and actually have bolt holes to bolt chevy or olds motor mounts in.

posted by  adamc44

I wonder if a BBC would be harder than the caddy? just a thought

but yeah theres countless ways I could go with this car lol

posted by  nighthawk

i dunno on the bbc, i havent been aorund any of them to give my :2cents: . you would prob run into alot of the same problems. id just get a 350 and work it over. it would be alot easier. you could get the gears changed too, i think, its a 7.5 rearend or 8.5 im not real sure.

posted by  adamc44

almost all of them are 7.5. the only one that werent are the grand national and the hurst olds, and even some of those didnt have the 8.5. you can squeeze a bbc in there as the mounts are the same, you just might have to shim the mounts about a 1/4 inch. they make headers for the swap and can be had from either summit or jegs. if you plan on doing this and running a true dual exhaust, make sure you get the aftermarket crossmember made by g-force or cut and weld your stock one in the right spot. if you have anymore questions please ask, i've have succesfully built 2 g-body cars, and am about to start my 3rd.

posted by  glagon1979

I figured you'd stop by eventually lol,

how much do you think (or know) the 7.5 can take?
I guess a 350 would be the way to go after all,

posted by  nighthawk

they dont hold very well at all without ALL aftermarket parts (ie. aft market axles, center section, etc) i have a friend that has broken 2 this season alone at the track and he runs a 350 with about 450hp. i know 8.5 rear ends out of a chevelle will work as they are about 1" wider than the 7.5 in the g-body and they have the same locations for the spring perches. there is a guy taht runs a very stout 396 bbc in his monte ss at the local track and it seems to hold up fairly well. if it were up to me on my next build, it would get a 454bbc with a th400 trans w/brake and a 12 bolt posi out back but thats just me. anything can be done with enough$$ and knowledge.:thumbs:

posted by  glagon1979

You might want to look for a 500 from a '71 Eldo. In that year they came off the GM-line with 500 HP - one HP per cubic inch. I had a '71 Convertible - it SCREAMED. The Transmission - good luck on it, I've seen GM truck tranny's used (but only on Caddy's commercial chassis on coach-built hearses). The block is designed to accept the T-475 transmission a real stump-puller - but, of course, that's intended to drive the front wheels - doubt you wanna go there on your GP (if you did that engine would twist the nose right off it like a twist-tie). 500's are all torque - the tranny and strengthening every drivetrain component is your toughest task and might push cost way up. Maybe an old ambulance? The same motor - all set up for rear-drive (just add-in MAJOR-league shortening of all components).

posted by  customcadillac

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