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My Cutlass S is the low compression 2 bbl engine. So naturally it had the single exhaust with the crossover pipe. I have never heard of or seen any other manifolds for the 350's back then other than the singles. I do not have a parts manual so can't look there. So my question is were there different manifolds for cars such as the W-31 or did they use the same ones with the silly block off tube? Fusick shows dual exhaust manifolds for the 73-77 350's. I would also ask if anyone knows if they dump in the same locations or would I need a custom exhaust? I just can't stomach the crossover block off pipe any longer. I am rebuilding my motor to similar to W-31 specs as far as compression and cam are concerned and the single exhaust manifolds are unacceptable to me. I am also putting a 4 speed in place of the TH350. I am not interested in headers. The factory W-31 had plenty of get up through factory manifolds and that's good enough for me. So what are my options guys. Thanks.
Yes, the W31 had the silly block off plates. Thornton 350 manifolds are a mild improvement, 2 1/8" outlet vs 2" factory and slightly larger internally. Also no silly block off plate.
So these Thorntons you mentioned, are these what Fusick is selling or are they different?
Oops! I see that what Fusick has fits 70-73 not 73-77. That should dump right where I need it.
I currently have. Set of the Thornton 350 JR’s finger tight on my 67-330 waiting for the day it gets runnin. I bought them from fusick (last set). Problem passenger side bolt holes were drilled one bolt size bigger than the drivers side. My suggestion is to really inspect them when you get them. I found out to late. Good luck
You might also look at the Thornton 350 shorty headers - assuming price similar between those and the repro manifolds you're considering, would be a nice and functional upgrade to your exhaust without the headaches of a full low-hanging set of headers. I just recently replaced my factory 350 manifolds with them and like them. If you're running a shop-built dual exhaust running up to your factory manifolds you'll likely have to have the downpipes modified to retrofit onto the headers though, as non-factory dual exhausts are not typically exact matches for a factory pattern. I ran into that when installing mine and had to have my shop modify the pipes to fit - minor setback but worth the final result.
I currently have. Set of the Thornton 350 JR’s finger tight on my 67-330 waiting for the day it gets runnin. I bought them from fusick (last set). Problem passenger side bolt holes were drilled one bolt size bigger than the drivers side. My suggestion is to really inspect them when you get them. I found out to late. Good luck
Good info. Thank you, I will definitely inspect them closely as soon as I get them. When did you buy yours? You said last set from Fusick. Is that recent?
You might also look at the Thornton 350 shorty headers - assuming price similar between those and the repro manifolds you're considering, would be a nice and functional upgrade to your exhaust without the headaches of a full low-hanging set of headers. I just recently replaced my factory 350 manifolds with them and like them. If you're running a shop-built dual exhaust running up to your factory manifolds you'll likely have to have the downpipes modified to retrofit onto the headers though, as non-factory dual exhausts are not typically exact matches for a factory pattern. I ran into that when installing mine and had to have my shop modify the pipes to fit - minor setback but worth the final result.
Unfortunately I have tried to convince myself with several sets of headers on several different cars and I always wish I hadn't. So for regular street driven cars, I won't even consider them anymore. I'm glad you are happy with yours. I have many friends that think I'm mental, but tomato - tomato, they're not for me on a street car.
I know I'm jumping in a little late to this thread, but the Thornton 350JR manifolds are all you need for a milder street 350. Since they are patterned after the W30 manifolds, you'll need these DOF10S downpipes to connect to the manifolds. The Thornton headers also have the same footprint as a BBO manifold, so you'd use the same downpipes. They are worth some power, but not as much as a good four tube header would be with it's superior scavanging.
I bought the headers from fusick in about the Feb time frame. Sat in the box, put them on finger tight and oops.Fusick said they would look at them under my dime for transport. I called the wholesaler over in the Philly area, they never heard of such an issue. Damm my luck at times, well the car still is not runnin, but near future. Good luck again
