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Does anyone know if it would be possible to swap out my HT4100 for a 500 on my 84 Coupe Deville? Would i have to make significant modifications?
 

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95 FWB 81SDV 96 FWB 94 Fleetwood
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This has been asked many times before...It can be done bolting in stock parts...the best thing to do is get a donnor car, a 77-79 full size caddy...all the parts[almost] , not the 500, can be taken off to do the swap....
 

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'80 Fleetwood Coupe, 1994 and 1995 Mercedes 140 Coupe
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Try the search feature of this board. There are lots of posts on the exact subject. It takes practice to find everything.
 

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1981 Sedan DeVille Diesel
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Aside from search results you may find, I'll just quickly add that it is a relatively simple swap. However, it's not drop in and GO-RIGHT-NOW weekend swap; count on drivetrain, electrical, exhaust modifications, etc... Engine mounts, oil pan and pick up, fan shroud, brackets and pulleys from 77-79 425 cars and 80-84 368 cars are biggies for the swap to plop on the 500 (or 472) in.

I have a 507/TH400/Locked 8.875" in my '83 Coupe and a 425/200-4R in my '84 Fleetwood... Any questions/problems let me know.
 

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89 2dr. Fleetwood 82 Cadillac Fleedwood
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I am in the process of placing a 425 in a 82 4 door Fleetwood and would like to keep the 2004r. I have a donor car, a 79 2 door that has the 425. I noticed that "472" has a 425/200-4R combination in his 84 Fleetwood. I would be interested in knowing what parts were needed to make this transplant since I am tring to make a similar swap.
 

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1981 Sedan DeVille Diesel
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kentyk, just treat the nose of the 82 as the nose of the 79 and swap it ALL over for an easier swap; radiator, fan, fan shroud, radiator support, all engine pulleys, belts, hoses, accessories, and brackets, P/S hoses, engine mounts, you name it. You'd be best off replacing stuff like mounts, belts, hoses, etc of course, but you get the idea. The only thing to be aware of is clearance on the passenger control arm; stock exhaust manifold may clear, while the 472/500 rwd manifold will require the arm be trimmed/notched with the front-most adjustment bolt holding the shaft cut flush with the nut. The 200-4r has the bolt pattern to allow for the 425, but the flexplate does not. The 425 plate "may" allow for the second pattern to be drilled into it (that's where I'm at right now, haven't dropped it in yet) - there are aftermarket SFI flexplates for BB-Cad engines on ebay for just under $100 if that doesn't pan out. We'll see... Another thing about the transmission is the importance of the TV cable for the 200-4r; it is critical that it is connected and adjusted accurately. The bummer of the 425's Quadrajet is that is doesn't have a provision for any transmission related cable (since the th400 has an electronic kick down). A bracket can be bolted to the location where the factory kick down switch used to go with two small screws - however this doesn't clear the intake (not a pre-egr 472 intake anyway), so a carb spacer is required, and custom bracket of course to hold the TV cable. A good cheap trick I found was cramming the 80/100 amp alternator from the 4100 into the stock 425 bracket (had to widen the adjustment hole in the top bracket). Lastly, I wanted to use the stock dummy lights so I'll use the 4100 temp sensor with a reducer bushing, and the oil pressure sending unit is actually the same so it should plug right in. That's all that comes to mind right now - the build 507 in my Coupe was really a start from scratch custom/alter/modify/performance thing so there was a lot of custom things that took a lot of time. The 425 into the Fleetwood I'm hoping to make a relatively simple swap and not hack too much out of the car. Hope that helps, and I'll let you know what else I run into as I got with the 200-4r.
 

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89 2dr. Fleetwood 82 Cadillac Fleedwood
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Thanks for the information! I look forward to hearing from you when you get it running.

K
 
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