Thread: 500 Caddy/G Body Swap

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hi guys new to the site recently picked up a 9 inch similar to the one listed here and was wondering if you could possibly do a write up as to how to weld on the new brackets and what measurements are important. since my g body's new motor plus the nitrous would have eaten the stock 7.5 i decided this was the best choice for the money 4:10s with a posi drum to drum for 200. any help would be much appreciated. thanks.

dylan

You got a good deal on the rear end, at that cost you'll be $ ahead on a ready to bolt in unit.

I did a pretty complete write up over on

http://elcaminocentral.com/showthread.php?t=28724

The one thing I would also recommend is not to weld too long in one area to prevent the chance of warping the axel tubes.

When I bought the 83 I had planned on just using it for a parts car for the 84 so a title wasn't really all that important to me. Now that it's being built I'm going thru the process of getting good paper on it so for now the big hold up is the title. I should have a title in a few weeks but for now I'm not going to be putting and time or money in the body until that is resolved. Worst case is I can't get paper on it and I'll have all the 500 swap stuff done and ready to put in a G Body when I find another one that I like (with good paper).

This weekend I found out more about Cadillac pulleys than I think I ever wanted to know. Neither of the engines I have had a complete set of pulleys and brackets but I figured between the 2 I’d have enough to make it work. Want I wanted was run AC and PS with an HEI and no smog pump. Once I figured out that things weren’t lining up I went to a buddy’s shop who has a few Caddies sitting around. That’s when I found out that Cadillac ran the water pump off the smog pump Fortunately he also had a 70 Caddy sitting around that doesn’t use a smog pump so at I knew what to look for…..and to make it better the local wrecking yard I’ve dealt with for years happened to have a 70 that still had the pulleys and brackets on it.

I have the bracket on order to use a Sanden compressor on the 500, but it hasn’t come in yet and I wanted to make sure the belts would line up and clear the HEI. The 70 Caddy runs a dual belt setup on the AC/PS and I've read where a few guys have run into interference when upgrading to the HEI.

Being a bit impatient I started looking at the stock A6 compressor bracket on the 472 and figured out that with a little clearancing (basically opening the saddle portion where the compressor sits and enlarging the bolt holes slightly) it would work on the Sanden. It fits so well I may just go ahead and build some rear brackets and use it instead. Every thing clears and the belts all line up so that part is figured out.

So at this point I now have the engine mocked up, a transmission and rear end ready to put into the body one I get paper on it.

Amazing what a bit of time with your friendly die grinder can accomplish, huh????? I build such weird stuff most of the time nobody makes accessory brackets, guess I'm just getting used to building my own same as you, Mike!!!!!--Does this mean we're cheap, weird, or creative????

Dave I'll chose answer D (all of the above).

One of my all time favorite alternator brackets is the 70's Chevy Truck/Corvette short waterpump unit. I've used them on all kinds of odd ball non SB swaps to include my Hemis. They used to be about $15 at the dealer but the last time I was going to pick up a spare one they have gone thru the roof (I think my cost was around $60....needless to say back to the wrecking yards ).

Nice wrap on the belts Mike, good job.

Thanks Richard. BY the way whats the weather doing up there. From what I'm seeing on the net looks like a good day to find an AC unit and cold one. We're getting heat, clouds and humidity (but no rain).

Originally Posted by Mike P

Thanks Richard. BY the way whats the weather doing up there. From what I'm seeing on the net looks like a good day to find an AC unit and cold one. Wetting were getting heat, clouds and humidity (but no rain).

Mike, if I had my druthers, I'd live in Sierra Vista. Been there several times to look around and loved it. But all in all, the short bout of tolerating the heat for a few months out of the year ain't all that bad.

On another note, just let me say that I always enjoy seeing you work on stuff. Everything I see tells me you are a master craftsman. There are a few on this board who qualify and you're one of them.

I found out a couple of things over the last couple of weeks, one is they are now using 10% ethanol here year around now. The cars that I have never had any vapor lock/heat soak problems with don’t like it very much, especially the heat soak thing. It hasn’t been bad enough so far to leave me walking, but it is aggravating. I think it’s a combination of the heat (a tad over 100 degrees) living 4500 feet and the poor gas. I remember reading a while back that they are proposing an even higher percentage of ethanol so I suspect things will only get worse.

Anyway this led me to start considering what besides the obvious things like fuel line routing, 1” Phenolic spacer and good fuel pump(s) I would need for this project. One of the almost sure cures I’ve used in the past is to run a return line to the tank so the fuel is constantly in motion and doesn’t have a chance to heat soak

I’m going to rebuild and use the original Q Jet from the Caddy so I took a look at it. One thing I had never really noticed on these before is that many have an aluminum soft plug located in a cast boss at the front of the filter housing.

I thought this would be an ideal place to put a fitting for a return line. I’m planning on running an electric pump located at the tank in conjunction with a stock mechanical pump on the engine. My thought is even in a situation where the engine is shut off and the fuel in the lines heat soaks, running the electric pump for a few seconds should clear any vapor and hot fuel from the line clear to the carburetor.

I went ahead and drilled an 1/8” hole in the plug and used a small body work slide hammer to pop out the plug. The resulting hole was just right to run a 1/4” pipe tap thru without any further drilling.

A few fittings and I had it set up to run the line back to the tank.

The real key to making this work is to restrict the fuel in the return line so that the fuel pressure remains high enough to feed the carburetor but passes enough fuel to prevent the fuel from staying in heated areas too long to vapor lock. I’ve had good luck using a restrictor with a 7/64” hole in the past so this is going to be my starting point.

What I did was to tap the inside of the of the 1/4" pipe used to connect the two 90 degree fitting for 1/8” pipe thread. I then took a recessed 1/8” pipe plug and drilled the 7/64” hole thru the center of it and screwed it into the threads on the inside of the pipe. If I have to fine tune it with a bigger or smaller hole, the recessed hex on the plug makes it easy to remove and replace.

As it stands right now, I’m planning on running a new 3/8” fuel line from the tank to the fuel pump as the Cadillac engine has the pump on the driver’s side instead of the passenger side as the El Camino is currently set up for. I’ll probably use the existing 5/16” fuel line that used to be the supply line as the return line and route it to the vent fitting in the sending unit. A vented gas cap should be the only other thing I’ll need.

Ethanol does not like heat, Mike!!!! We run a cool can on the drag cars, both are on E-90, and going to be fabricating one for the 'maro, it'll be on E-85.... Another change we've gone to is to run a return line from the regulator, or a bypass pill, on everything with ethanol in it..... Just 10% ethanol will do much better just by paying close attention to line routing as you are doing.....

".... Ethanol does not like heat, Mike!!!! ....."

As I'm finding out Dave. Doing the return line on this build does not bother me that much as the fuel system will be part of the overall build and done in conjunction with everything else. It's having to back into cars that are “done” (primarily the 57 Plymouth and the 76 Dodge truck) and retrofitting return lines and taps into the tank for the fuel to go to.

If I remember what I read correctly they were talking about raising the ethanol level to 15 or 20%. From what I’m seeing it would almost make the Plymouth and Dodge undrivable in the summer without adding the return lines (not to mention the performance/mileage losses even with retuning).

A lot of guys here are starting to build E85 specific vehicles right now, but I personally am not quite ready to make that jump yet, although on the this swap I will be looking at things to make the conversion down the road easier should I be forced to go that route at some point.

If for no other reason Mike, I like E-85 for fuel specific engines in this area because it's readily available, and has 105 octane---which means I can finally again build in some higher compression and buy the appropriate fuel right at the pump--for less then the price of regular gasoline.... Compression is horsepower and I do dearly love horsepower!!!!!

"......Compression is horsepower and I do dearly love horsepower!!!!!......"

I hear you Dave. My reluctance right now comes either having the engines already built for and or in the cars I would consider for the conversion or I’m building something that I plan on driving on vacation and am concerned about availability on the road.

I’ve still got a couple of builder motors out in the shed, so I do suspect that at some point I will be doing one……..of course that will require another body to put it in, ( of course there IS the wife’s Mustang II Couple and that 472 Caddy )

I was thinking about your return line build.
I've owned a few Eldos (472, 500, 425) and the version of the fuel pumps had the three line set up. Third one being for the return fuel so fabrication wasn't necessary off the carb.
I was thinking that the fuel filters available for Fords and Chryslers that had the restricted fuel return line built in the to help clean up the fuel line fabrication for you Caddy set up.
Just my .02 cents worth.