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Rescued a 73 Supreme from a barn a couple years ago. Engine was seized. Upon further inspection, one of the heads is cracked.
Car is otherwise in excellent condition. Interior looks great. Pulled the motor. Considering 455 upgrade.
I'm open to suggestions or any input from the group.
I would probably go with a nice warmed over 403. Very few people could look at it and even tell it is a 403. Then you don't have to worry about AC and power steering brackets.
I would probably go with a nice warmed over 403. Very few people could look at it and even tell it is a 403. Then you don't have to worry about AC and power steering brackets.
Great points. Good call. You can work a 403 very good.
I didn't realize it was green until it was pointed out. Great save. Is that mold on the seats? How did you remove that? Bleach? Cool cool car. Good on you giving it love. Great colors.
What a beautiful car! I recently told someone if I could get another 72 to pair with my black one that color green would probably be my first pick. Very, very nice!
I ended up finding a 403 and the teardown begins soon. Car has new brakes, suspension, fuel tank, fuel lines and transmission rebuild. Basically just waiting on a motor.
One question though. This car had a Gold motor and everything I'm seeing is that anything 1973+ has the corporate blue.
Why is this one gold? It is the stock motor.
I'll end up keeping the 403 gold when it is time for paint to keep it as original looking as possible.
I'd put a 350 back in it. Once of the things I hear about why many don't drive their old car that much is the things gulp fuel. I find it silly. but that is why they don't drive it much.
I'd rebuild the 350 for 300 ish h/p and call it good. A 455 isn't going to make it faster. without money spent on the chassis. The 350 will fry the tires just as well as the 455.
Now if you already had a fully dressed 455 just sitting in a corner with a th400 bolted to it. Then sure.
Last edited by CutlassMarc; Aug 1, 2025 at 02:52 AM.
x2 on the 350, IMHO it's the better choice as that was what was already in it. A 350 will be more versatile than a 455 if you are looking for some economy. Heck you can even put in a 2 barrel carb if you want, with a 350. The 403 is from a different era.
Just now seeing this, WOW did it clean up good. Sounds like you already have a 403 in hand, so understand your desire to go with what you have. Its still a SBO, so I'll still play the part of a 350 cosmetically, However, a 76 & earlier 350 is a much stronger block than the 403 and can be built for more power (even stroking it to 428 as I'm planning for mine). Anyhow, NICE find and glad to see another '73 get rescued.
I ended up finding a 403 and the teardown begins soon. Car has new brakes, suspension, fuel tank, fuel lines and transmission rebuild. Basically just waiting on a motor.
One question though. This car had a Gold motor and everything I'm seeing is that anything 1973+ has the corporate blue.
Why is this one gold? It is the stock motor.
I'll end up keeping the 403 gold when it is time for paint to keep it as original looking as possible.
My car started its life with a gold engine, and during a rebuild in the 80s I painted it blue. Then in the 90s it went back to gold. My point is don’t worry about the engine color.
Regarding the 403 vs 350 dilemma, note the 403 in its factory state with 8:1 compression and a puny camshaft had 320 ft-lbs torque.. That’s significant, and the 403 is the same external size as the 350, so you get more CID in the same size package. Build it right and it will be very powerful, while still being driveable.
my car started its life with a gold engine, and during a rebuild in the 80s i painted it blue. Then in the 90s it went back to gold. My point is don’t worry about the engine color.
Regarding the 403 vs 350 dilemma, note the 403 in its factory state with 8:1 compression and a puny camshaft had 320 ft-lbs torque.. That’s significant, and the 403 is the same external size as the 350, so you get more cid in the same size package. Build it right and it will be very powerful, while still being driveable.
My car started its life with a gold engine, and during a rebuild in the 80s I painted it blue. Then in the 90s it went back to gold. My point is don’t worry about the engine color.
Regarding the 403 vs 350 dilemma, note the 403 in its factory state with 8:1 compression and a puny camshaft had 320 ft-lbs torque.. That’s significant, and the 403 is the same external size as the 350, so you get more CID in the same size package. Build it right and it will be very powerful, while still being driveable.
