heya guys i guys got a mid 70's cadillac 502 cid big block complete with tranny ready to drop and play, any one have and ideas on the goabout of this kinda swap?

 

500 CI engines are made to get your grey haired grandmother to the grocery store and back...at 2500 rpm, there isnt alot of potential for those motors execpt as airboat motors cause they peak around 3000 RPM. Sure you can read in some magazines were they got the car in the 12's but you really have no clue how much money it takes to get such a POS to get there.

 

Actually it's a 500. The 500 was made from '70 to '76 from then on they switched to the 425(same externally) up till '79 when they came out with the 368(same externally as well). Actually these motors are BIG torque monsters. A fresh rebuilt stock no cam no nothing 8.5:1 500 makes 302hp and 493 ft lbs. Personally I disigree with it being a POS but I will say it'll cost a hell of alot more than a 350 and a little more than a comperable chevy big block(but the caddy weighs less each head alone weighs 30lbs less). But Aron a stock 350 makes it peak hp in the 4000 or 4500rpm range. About the only disadvantage I can think of is parts cost and availibility.

 

It's been done I think 430T/A has a late 60's 430 Buick Engine in an Thirdgen Trans Am. Try and PM him and he should be able to give you some help. Don't underestimate the 500 Caddy (Not 502 c.i.) they came from the factory with 400hp (but that was gross rating) I would think if you could find A nice Hi-Po Caddy cam and intake and then Port and Polish those heads you might have one hell of an engine. But it wouldn't be a High Reving engine.

I know my brother has a '29 Ford Tudor and he is going to put a 500 Caddy in the frame rails (But that car will only weigh about 2200 curb weight) :hail: .

But do a search on the internet for Big Block Caddy Performance Parts, who knows there maybe more out there than I think?

Later, Garrett

 

Damn you CaddiBird You beat me to it. OK 3 minutes but I type slow.

trans_am_Racing you might want to go to some local Swap Meets and maybe find some gems.

Later, Garrett

 

hehe I'm a Caddy freak. As you can tell by my sig I've got a '76 500, it's bored 30 over(making it a 507), has 2.10/1.77 stainless valves(for a 400 pontiac, hey they work), SBC valve springs, a 425 mid sump pan made into a rear sump, Comp N20 BBC cam ground on a Caddy core with .575 int and .587 lift with 230 and 244 @ .050, Edelbrock Performer intake and right now I'm working on a homemade shaft rocker setup using Ford FE rockers. Theres one guy that has a 80's Cadillac with a 500 in it mildly built(same combo I got except a little less cam and ported heads) and it runs 11.87 in the 1/4 and the car weighs 4200lbs, using get this; 2.72 gears! My motor still sits on the stand but it should be ready to drop in my car soon, I just need a job to get more cash so it'll be alittle while(gonna wait to when I hit 18 in about a month for a better job). I can't wait to get it running the neighborhood will never be the same !

Oh yeah some cad links

http://500cid.com/frames.html Maximum Torque Specialties
http://www.cad500parts.com/ Cadillac Motorsports Develoment

 

I agree the caddlilac engine is under appreciated. The 1970 472 engine was 375 hp 400 lbs torque. I do not know if it will fit in the f-body. These engines have large dimensions. Get out the plasma cutter!

I rode in a 76 trans am with a buick 430 in it. The car was sick fast. It barely kept the front tires on the ground.

 

actually it is a 502 its a 425 cid motor bored to a 502, already have all the tools to chop the frame to whatever way it fits, already have some pics of what ive done to my 86 ta for the 350 thats in it now, but thats gonna have to be re arranged, but anyways i was thinking of getting a heavier front end and completely redoing the frame structure with an 1 or 1 1/2 ton front end ?!?. i already have custom Sfc's that i designed to take alotta torque. im going to be taking the motor to a 540 cid, eventually when i can afford it, but for now the 502 will do : )

 

Yeah you will have to beef up that frame big time. I wonder if you can use 455 springs from a second gen.

 

Let's See the 425 had a 4.080" bore and a 4.060" stroke. So in order to make a 425 into a 502 (only by boring it as you stated) you would have to bore the motor over .355" !!! I know Cadillac Motors are beefy but not that beefy.

Sorry Man but I have to call on the 425 bored to 502 Caddy.

Later, Garrett

 

Believe or not they are. They used on block for all of their combinations. They d-boared and d-stroked all the way down to 368 cid. These blocks are monsters. One of my first cars was a 70 deville with a 472 and TH400 trans with posi (which was developed by Caddilac.)

The engine produced so much torque it could keep that weight moving with no effort. The car would climb most hills while maintaining constant speed without additional throttle.:hail:

 

yeah and chevy used the same block from the 283 to the 400 try boring a 305 to a 350...I'll call in with the BS also!


The only block Ive ever seen bored more that a .125 was a Model A ford.

 

Not B.S. As far as I am aware CMD only produced big block engines. I have seen all flavors of the caddilac engines and they look exactly the same. Growing up one of my old neighbors owned a gas station that serviced a feet of caddliac limos so I had a lot of exposure to those engines.

You have a point when taking a smaller engine and making it bigger, however I see absolutely no difficulty in taking a big engine and making it smaller.

This is exctly what CMD did in the early 80s giving us the 425 and 386 engines. Proir to that the only two options from 1970-1977 were the 502 and the 472.

 

Ok let me get in on this. The 368 and 425 use diffrent blocks then the 472 and 500 which used the same block. A 500 has a 4.300 bore and a 4.304 stroke. The 472 used the same bore but has about 4.060 inches of stroke. As I stated earlier the 368 and 425 each use their own blocks. The 472 was made from 1968 to 1974 and was used in all RWD cadillacs. The 500 came out in 1970 and was used to 1974 ONLY in front wheel drive Cadillac Eldorados with a TH425 trans axel that wraps halfway around the engine then starting in 1975 they put the 500 in all cadillacs because they droped the 472 in 1974. Then in 1977 they came out with the 425 which looks identical except for a flat spot on the valve covers and a scaloped crank flange, they quit making the 425 in 1979. The 425 and 368 look the same on the outside as the 472 and 500 but they use diffrent heads(smaller ports and chambers) and diffrent blocks(thinner wall thinkness on the bores as well). It's like comparing a 350 to a 400 they look similar on the outside but are completely diffrent on the inside.

 

Thats the point I was trying to make. But you added the good info facts

 

Thanks for the clarification. I have been mulling this over in my head. I assumed they would change the volume in the heads, but I did not figure they change the cylinder wall configuration that much. Was this done to save iron?

 

I would assume they did it to save on costs(10lbs of cast iron ads up on a half million engines) and to save weight. Plus the fact that it's just not needed. As for the heads smaller bores need smaller chambers to keep the compression up(68 to 73 engines had 76cc chambers, 74 to 76 used 120cc and the 425 uses a 96cc chamber, don't know about the 368), actually you can use a 425 head on a '74+ 500 to gain some compression but it's been argues on other boards that the smaller ports make it not worth the added compression and on stock motors. Hell, the dyno shows it as a 10:1 500 makes 323hp to a 8.5:1 500's 302hp. The claims of 450hp and 550 ft lbs of torque are of the old(and highly wrong) rating system seeing how the 450hp is claimed at 4400rpm(if my memory is correct) when these motors with stock valve springs, at a massive:lala: 60lbs of seat pressure, will start floating the valves at about 4000rpm(I actually saw it on my motor when I tore it down there was two valve indents in all the pistons from the valves hitting the piston). Wow I guess I started to ramble a little here lol anyways for more info on these motors and for performance parts check out the two links I posted earlier, especially MTS they have a boat load of info on their site about these motors.

 

Thanks. Please post pics of that swap.

 

Don't have any with the engine in car as the engine is still on the stand(wanna donate some money? $250 will get you 3 free rides with all other rides over 3 costing $25 LMAO). But I do have one of my car with flaking paint, mismatched rims(can't tell in the pic gold one side white the other), and minus the 2.8 V6 which I sold for $65!

 

Keep the apperance like that for a while when you are finished. That kind of sleeper will let you win a few dollars or pink slips on the street.

 

Here's some pics of my 86 im goin to be putting the caddy motor in goin to have to restructure the frame, was goin to keep the 350 in it till this winter but couldnt pass up the deal on the caddy motor and trans .

p.s. i dont know if the motor is a 502 or not, thats what i was told when i bought it, i wont know til i rip the crank and stuff out to get their numbers, but i was told it was a 425 bbc taken to a 502,
so until i get the numbers i cant tell you for sure.

Here the link to the pics, there are 28 of pics total, so it may take a min in loading the page sry.

http://www.rochelle.net/~playa01/86tapics.html

 

Wow. Looks like it had a salt bath. This project will be great for your welding skills.

 

here a link about cadillac motors and what was done to get there CI's from the same block



http://500cid.com/mts/cat/tips.html

 

 

Dude, you dont get it....yeah externally they are the same, but just like a SBC they aint the same on the insides...just like you cant bore a 305 to a 350, your not taking that much out of the bore to get your number.

 

Ok another reason why I doubt you can bore a 425 to a 502 is you'd need a 4.435" piston which gives 501.8ci meaning you have to bore .355 out of the cylinder. A boring bar(used to bore a block) can cut about .030 at a time meaning you'd need 12 cuts per cylinder and would take all day or maybe even two days to bore all the cylinders. Also where would you get a 4.435" piston? The only way would be custom made and were talking big $$$$$. Also if you were to bore any block .355 you'd remove all of the cylinder, there be nothing left. Trust me on this man it's either a 425 a 472 or a 500. Even if it has been bored it would only add about 6 or 12 ci depending on the stroke of the crank and if they when't .030 or .060 over.

 

Any caddy eng updates? I need to know if I'm the lone bird running one of these babies!

 

Redraif and I have two 500 Caddy motors; one is still at the machine shop (Ross pistons, 10:1, 6.8 Eagle BBC rods, balanced), the other is a freshly rebuilt one we pulled from a purple metalflake 72 Eldorado convertible at Pull-A-Part. The "good" motor is going in her 90 Chevy exteneded cab dually, the other into a '76 Scout 4x4. With a decent set of BBC rods and shaft rockers (about $350), the 500s can rev just as well as any other big block, but the thing is they don't need to...when you can easily make 600hp and 650 torque, who needs to spin the crap out of it? The crank and block will take anything you throw at them...the guys at MTS have even run over a 200 shot of nitrous on the stock cast pistons, with no ill effects.

 

I have a 500 in my 84 trans am. The low speed torque from these engines are amazing.