Hey Guyz, I'm trying to help a friend. He bought a 1940 Ford coupe with a J-2 equipped 48 or so Olds motor in it. The motor has stock exhaust manifolds that seem to 'dump" in all the wrong places. I would imagine that Olds made a few different exhaust manifolds ?? Anybody make Headers for this application ?? How about Header Flanges ?? Any help would B greatly appreciated. NaCifan.
Oldsmobile offered the J2 option in 1957 and 1958 on their 371 ci engines. There were many exhaust system options available back then, but they're hard to find these days. Make sure you know exactly what you have before spending any money on parts.
The factory 303/324 manifolds come in left and right. The left (driver) dumps straight down towards the front of the manifold. The right has a horizontal “dump” towards the rear of the manifold. The factory idea was that the driver side dumps down, runs somewhere underneath and across to the passenger side, which then went straight out the back. Fenton and possibly a few other aftermarket guys made cast iron “headers” which dump at the rear and go for a lot of money when you can find them. Otherwise if a combination of the factory manifolds doesn’t work, your buddy is probably going to have headers made.
These flanges will work if it's really a 303, they also make flanges for 324, 371 and 394 heads... https://www.hellsgatehotrods.com/shop/oldsmobile-303-exhaust-flange/
Many years ago, I found a '47 Mercury with a 303 Olds in it, and scarfed the Hurst mounts and standard shift flywheel from it. Whoever did the swap bolted the exhaust manifolds LH on the right and RH on the left, so the outlets were more or less facing up, and ran the pipes out through the inner fenders. Crude, but effective.
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