Cadillac 502 Engine
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msmith1956
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It can but requires a huge amount of work. You need a GM TH425 transaxle from a Toronado/Eldorado from the early 70's and the engine has to sit north/south. Here is a pic of a Fiero with a big block:
Good God, what a beast!
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Yeah im really exited for this swap. 8.2 L, 502 horses. Don't know if my gas tank will support this though. Heres a picture of the one im thinking of getting for $500:
http://postimage.org/image/z6hjkvekt/
http://postimage.org/image/z6hjkvekt/
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Zimgxp
New member
Keep us informed on how the swap goes. Pics too.
What year engine is that? The horsepower depends on the year of the engine. The Cadillac "502" is really 500 cubic inches. The term "502" stood for 500ci and dual exhaust. Not how much horsepower it had.
Here is the gross horsepower rating by year:
The 1970 was 400hp (only year with 10.0:1 compression)
1971 thru 1973 was 235hp (compression dropped to 8.5:1)
1974 and 1975 was 210hp (more emission controls were added)
1976 (final year) was 190hp (there were a few with fuel injection that were rated at 215hp but these were limited production/special order)
The gas tank will support it but your gas mileage will be low. If you drove it easy you could probably get 14mpg which means you could drive about 140 miles on a tank. Hot rodding probably around 80 miles. Depending on what was originally in the Fiero will depend on which electric fuel pump is in the tank. The 4-cyl fuel pump with a standard regulator is what you will need to run a carb'd engine.
Sounds like a fun project. Keep us updated.
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Zimgxp
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Not sure why it wouldnt be legal. My.02, I know you want to upgrage the motor. But at only 200 hp or so there are more swap friendly motors that will give you more hp. Don't get me wrong, I would love to see this done. Just playing devils advocate.
Yeah i know there are much better engines out there but im running on a really limited budget but any suggestions for better alternitives that can be found for under 1500 would be greatly aprecciated.
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CatSkinner
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Without a lot of bucks, 3.8L SC can produce well over 300 HP and weighs a bunch less than a big block.
Are you sure you can find the parts to modify it? I doubt there are many performance parts that fit a Cadillac 500 V-8. I can see there are a few performance intake manifolds but no performance heads or even headers that fit that engine. With limited parts modifications for performance will be limited as well.
In all honesty there are many better options out there. The 3800SC can get you more power stock and about 250 lbs lighter than the 500. If you want to go with a V-8, A cadillac 4.9L has the same horsepower, weighs about 20 lbs more than the stock V-6 (it's aluminum) and bolts up to the stock transaxle. Or if you want to stick with caddy engines, the Northstar V-8's work as well. Then there is the chevy small block's that can go from the old LM1 @ 275hp up thru the 500hp LS6. If you want a big block, The Chevy Big Blocks would be a better choice because there is a very huge aftermarket for the engines. Things like aluminum heads to reduce weight but increase performance, a huge selection of cams, pistons, intakes, etc.
I am not saying you should not do the swap, Just before you sink a lot of time and money weigh your options so that you can accomplish what you want to do.
superdave
New member
I have read thru all this... you must realize that most successful swaps have already been done. Not saying that others may work, but honestly, the cadi 500 and the 389 pontiac are boat anchors... high weight, low power for size.
If you GOT to have a V8, go with the Northstar Cadi V8.... its been done many times, a lot of information how to do it is all over the WEB.
If I ever want to go V8, I will go Northstar.
Oreif is very knowledgeable about these matters, you should listen to him... Asking about old random engines will have the same answers.
Good Luck...
If you GOT to have a V8, go with the Northstar Cadi V8.... its been done many times, a lot of information how to do it is all over the WEB.
If I ever want to go V8, I will go Northstar.
Oreif is very knowledgeable about these matters, you should listen to him... Asking about old random engines will have the same answers.
Good Luck...
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Pontiac engines are larger than a small block V-8 so again it will not fit transversely. If you want a V-8, There are plenty of V-8's with more power and lighter weight. A LS2 small block chevy weighs only slightly more than stock and has 400hp without doing ang mods. A 1966 389 was rated at 360 gross horsepower. By todays ratings it would be around 300hp. If you want a big block, the Chevy 396/427/454 engines would be a much better choice. You can get aluminum heads and lighter weight parts to keep the weight down as well as a huge amount of perfomance parts that are available and less expensive then other engine parts.
Not to discredit the value of power to weight ratio but wouldn't a moderately light car such as the fiero want extra weight in the back to get better grip when coming off the line to prevent from just smoking the tires?
The Fiero is mid-engine so any engine swap keeps the weight near the middle. But adding 300 lbs will still make it slower. Typically .1 second for every 100lbs. So going from a 350lbs to a 450 lbs engine is not too bad, But going from a 350 lbs V-6 to a 660 lbs cast iron big block will have an effect on acceleration as well as handling.