Build: Cadillac 500cid

[csbuckn]

So here she is:
1975 Cadillac 500cid

So after a 7 hour round trip almost to Canada and 100 bucks later, its in the garage. I'm not exactly sure how big I want to go with this but it should be a strong build. I have a TH350 to go with it. I plan on putting it in my 90 FWB 350 unless I can find a coupe for a post recession price. But there are some things I'm unsure about...like the new motor/tranny combo. Switching from a fuel injected 350/700r4 combo to a carbed 500/TH350 has me worried about the wiring and the axle/rearend. Is there gonna be a need for a new axle and crossmember? Wiring is probably gonna be a whole other story... Any suggestion would be helpful. Does any body know where the casting numbers are on the block or a nice website with info about the motor?

[csbuckn]

I didnt even think to check THIS site for more info. Google search brought me right back to the 500/472 threads here. One day I'll find the instruction manual for this brain of mine...probably missing pages

[Stingroo]

Originally Posted by csbuckn

I didnt even think to check THIS site for more info. Google search brought me right back to the 500/472 threads here. One day I'll find the instruction manual for this brain of mine...probably missing pages

lol Yeah. I've figured out that if there is a question about a Cadillac ANYTHING, the answer is probably on this site 99% of the time.

[jayoldschool]

I'm going to keep this thread here (and not the big block engine section) because this will go in a RWD car, and lots of members have shown interest in the swap.

You will need a TH400 or a 4L80E behind that 500. A BOP TH400 will bolt up but lack OD, the 4L80 will need an adapter plate, and an electronic controller (and likely some floor pan massaging).

To get it in:
- mounts from an 77-81
- oil pan from an 80-81
- grind the passenger side a arm bolt where it will hit the exhaust manifold

The rear axle (the GM 8.5) is strong enough. I would try and pick up a 94-96 B or D crossmember and adapt it so you can run true duals. There are a couple of companies and websites out there that deal with 500 Cads. At a minimum, put a better cam in it.

How about using the Chevy 454 TBI, and a custom chip in your stock computer and making it FI? All you would have to do is put all the sensors from the 350 into the 500.

[Angry Matt]

Check out these sites also...

http://www.500cid.com/

http://www.cad500parts.com/

MTS has a lot of good stuff for these motors and good tips on both sites.

[jayoldschool]

And, the most important question: are you SURE it's a 500?

[Stingroo]

Originally Posted by jayoldschool

And, the most important question: are you SURE it's a 500?

I was actually surprised this question didn't come up sooner. lol

[csbuckn]

I was thinking about different motor options but the caddy 500 means more to me. Where are the casting numbers? The only one I found is on the intake...605061 and the heads say A8. For the trannies, I have a TH350 and a 700 with a shift kit. If I use the 700 with an adapter plate, will I have to change anything at the rear? I already have true duals going down the passanger side but wouldnt mind an H pipe. Still unsure about fuel delivery, I still have that spreadbore/TBI adapter...?? Can I make the TBI spit more? So many questions because I want this to be my pride and joy. Would an 80 coupe do the trick. I found one but the body is too bad to use.

[jayoldschool]

Pull the pan and measure the bore and stroke. Best way to determine if it is a 500 (or a 472, or a 425).

That 700 likely won't survive behind the 500. However, since you have it, you could give it a try. If you baby it, it might live. You would already have the adapter to use on a 4L80...

Like I said, you could try getting a truck 454 TBI, and use that adapter plate. Even those injectors might be small for the 500. Raising the pressure might help, or, you may be able to get higher flow injectors to go on that throttle body. Someone on the truck forums will know. Once that is accomplished, you keep all the wiring from your 350 and use it on the 500. Then, you contact a custom chip burner, tell them all your specs, and have them burn a chip for your computer.

[csbuckn]

Oh, I see. I thought you meant the whole 454 instead of the 500. That TBI sounds like a great idea. What about the computer from a 454 TBI truck? I once looked into a custom chip and it was about 4 million dollars. When you say raise the pressure, are you talking about the vacuum pressure?

[jayoldschool]

Yes, I mean use the 500, but with the 454 TBI. It would be very cool.

The computer for your 350 is very close to the truck one. You could use the truck computer. Believe it will plug right in.

No, I am talking fuel pressure.

Check out http://www.tbichips.com/ for custom chip info...

[cadillac_al]

Gee, csbuckn, you're a busy guy, I can't keep up with your projects. So you're giving up on the 350 swap? Is that one of those AC Delco floor jacks you have there? I have been very close to buying one of those. How do you like it?

I'm not to crazy about Jay's fuel injection plans. That's going to make things much more complicated and the 454 SS had how much HP? Less than 250 I believe. A properly adjusted Quadrajet can run almost as smooth as fuel injection and once adjusted won't need any attention for thousands of miles.

What's with the red valve covers? I thought most Cadillac engines were blue; especially mid 70's. I hope it's a 500 but I don't recall ANY red ones.

[jayoldschool]

That's going to make things much more complicated and the 454 SS had how much HP? Less than 250 I believe.

All the wiring is there already. He has a TBI 350 in there. And, check the HP on the 75 500. 190 HP

[csbuckn]

I still have the Olds 350 on the stand. I have to finish that first before I can start the 500 but the 350s piston rings are giving me problems, I thought they came pre-gaped but I was wrong. That damn jack blew a seal in mid lift, its a Roush Racing jack. Can only get about 4 inches up but I may fix it if I need another. I know the motor is at least a 472/500 because of the design of the crank end. I've been reading on the TBI idea and read that stock 454 TBI can make over 400hp before it runs out of air but the fuel pump is only capable of 300 max. This gives me hope for the TBI setup with a new pump. I was thinking the stock intake, a one inch open spacer(mainly to help with even distribution), and the TBI setup.

[greencadillacmatt]

That's weird that you're having ring trouble on the Olds. Mine were fine and went on easy. What company did you get them from? Mine are Federal Mogul or Sealed Power. I got it with the Summit Racing re-ring kit.