500 in a 71 Chevelle

[artmalibu]

I was wondering what would be involved in swaping a 500 with a TH400 longtail from a 1976 fleetwood into my 1971 chevelle?

[Ted in Olympia WA]

http://mywebpages.comcast.net/caddycarlo/caddycarlo.html

This is not my car but it is a good web-site for you question.

TED

[Caddycarlo]

the car is about the same but your nose is shorter so you may have to push the motor back a little to clear the radatior ........

[Big-Daddy]

I'v got a 71 GTO [actually a LeMans clone] that's Caddy powered. Maybe I can help a little.

For starters, that MonteCarlo is a GM A-body, and under it's skin, is exactly the same as your Chevelle. Same frame, same firewall, same everything. So all of the information on that web page transfers directly over to your car.

My car was built with a set of Cad Company's motor mount plates. I like the Monte's upside-down SBC mounts, and if I had known about that trick, I would have used it. Your going to have to remove the lower controle arms to get to the bolt holes, and it's a good idea to spend a few bucks replacing the suspension bushings while your in there.

Also, I used an engine wiring harness from a Buick 350 Skylark. Again, it's an A-body, so it hooks right up. But more importantly, the buick 350 has everything in the same locations as the caddy motor. Distributor, sensors, etc. So it hooked right up to the engine without any modifications.

There is at least one guy here that used a "mid sump" oil pan from a late 70's RWD caddy 425 when he swaped a caddy into his G-body [78-87 Regal, Monte, Cutlass, etc]. The G and A bodie frames are actually quite simmilar, so this pan *could possibly* work for you, but the general consensus is that you need a FWD Eldorado 500 oil pan and pick-up tube to make the swap work. That's worth noting because 500 eldo pans are becomming extremely difficult to find, and very expensive when you do find one.

The long shaft T-400 is a bad idea. It's simply too long to work properly. While you could have your drive-shaft cut and shortened to work with it, it will mess up the pinion angle geometry and place a lot of stress on the u-joints. Besides, it costs about $250 to re-size a drive shaft. You could buy a good working BOP T-400 short shaft for a lot less than $250.

I took the power brakes off my car when I did my swap due to clearance issues, but you could use a smaller booster if you wanted to.

I also had steering shaft clearance issues, and my solution looks almost exactly like the one on the Monte Carlo. I also used BBC headers welded to caddy flanges. I'v often wondered if the caddy shorty headers would fit.

My rear-end is the stock 10 bolt with 2.73 gears and the factory posi. I use 255-60-15 tires on the rear, and believe me, it's a total burn-out machine. I know that tires as big as 295-50-15 would physically fit on the rear-end, but I dont want to overload the 10 bolt with too much power. The way I see it, spinning the tires is a little easier on the rear end compared to hooking up all that massive torque!

One last thing, your going to need front suspension springs for a BBC 454 Chevelle. Samll block springs sag a little too much, and it was very obvious when I first installed the caddy into my pontiac.

Other than that, you just need to remember that the caddy motor is a low RPM engine. Dont plan on buzzing it up to 5000 rpm or it will break.

Have fun!!!

[artmalibu]

Thanks for the info?

What would it take to get the 500 to move my car into high 12s with 3.42 gears?

[DV8]

High 12's? Depending on the condition (wear) of your engine, maybe not much other than the swap.

For a cheap way, get a set of 76cc heads from an earlier engine, have them gone thru, and crank that compression up! Run race fuel, and I bet 12's are yours......

DV8