Cutlass Supreme Exhaust System Questions

[rogue_ryder]

What motor is in your 442? I assume a 350. Thornton doesn't even have them on their site yet. They currently have tubular W30 manifolds which Olds people are really split on. This thread just came up on Classic Olds, the shorties look nice, I heard they were in development but assumed they were making 260-403 tubular manifolds.
https://classicoldsmobile.com/forum...-70-cutlass-dual-exhaust-pipes-suppliers.html

I've got the stock 307 in it for now, but I'm planning on swapping to 403 in the future. Thornton says they'll fit 307, 350 & 403 but I see no reason why they wouldn't also work on a 260. All SBOs are identical in dimension. Sure the size of the exhaust ports are the weak link on the smaller motors and no header is going to give you much of a power gain on those motors, but right now anything is going to be better than the beat and leaking long tubes on my car.

And even if they don't mate up with the downpipes from Pypes; cutting the flange off the pypes down pipes and welding on another is like a 15 min job and a few bucks material.

In an ideal world I'd have bought the ARHs but damnnnn they're pricey.

 

[olds307 and 403]

I've got the stock 307 in it for now, but I'm planning on swapping to 403 in the future. Thornton says they'll fit 307, 350 & 403 but I see no reason why they wouldn't also work on a 260. All SBOs are identical in dimension. Sure the size of the exhaust ports are the weak link on the smaller motors and no header is going to give you much of a power gain on those motors, but right now anything is going to be better than the beat and leaking long tubes on my car.

And even if they don't mate up with the downpipes from Pypes; cutting the flange off the pypes down pipes and welding on another is like a 15 min job and a few bucks material.

In an ideal world I'd have bought the ARHs but damnnnn they're pricey.

Yes, they will fit all those motors. I had Sanderson shorties with the same 1 5/8" primary tubes on a 260 with 2.5" dual exhaust, they improved power everywhere a 260 makes power, which is idle to 4000 RPM max, more like 3500 rpm. I also had them on a 350 and 403. Those Thorton's look similar except don't have a proper collector, looks like a bottle neck where the pipes join but it would occur at the exhaust collector anyways, being a stock size. Either way, a set up that can be basically bolted together at home is a huge win, win in my book.

 

[rogue_ryder]

Want to know how to make cheap long tubes fit?

The PO of my car had these "Professionally" installed! (A shop that didn't put the nuts back on the motor mount bolts and left the dipstick tube out of the car!) You can see they leaked at the flange (probably from day 1), and needed to be beaten almost flat to fit between the block and the frame rail of the car. This one is the drivers side, the passenger side wasn't as bad.

I have no idea what brand these are, but I have zero confidence in pretty much any budget long tubes out there for SBOs...

 

[olds307 and 403]

Probably G body or maybe even A body, but don't look like in the bends for them. I would put money on Flowtech's header, poor fit, thin flange and rust even through the ceramic coating in no time. The Hedman long tubes are much better and the Hooker better again but are $600 once coated. Post pics of the Thorton shorties when you get them and put them on.

 

[carnutjw]

What motor is in your 442? I assume a 350. Thornton doesn't even have them on their site yet. They currently have tubular W30 manifolds which Olds people are really split on. This thread just came up on Classic Olds, the shorties look nice, I heard they were in development but assumed they were making 260-403 tubular manifolds.
https://classicoldsmobile.com/forum...-70-cutlass-dual-exhaust-pipes-suppliers.html

Check out the Thorntons"shorty headers" Ebay link in Rogue Ryders post from Wednesday on pg 3. Don't know why Thorntons wouldn't have them on their website, maybe gauging response? Once you're on the Ebay page go down to the exhaust manifolds section under categories and will show you all their tubular and cast options. JW

 

[N3M3S1S]

On my 79 I lucked out and got the "buddy price" for a nice custom dual exhaust at a friend's shop. Can't beat that buddy price! I love it and I hope to slap some headers on because the factory logs suck. Then it'll be perfect.

 

[olds307 and 403]

One note Thornton's should put on the 1983/84 Hurst Olds or 85 to 87 442, is factory crossover pipe won't fit, which obvious but wouldn't hurt. The other one that isn't so obvious is factory down pipe on passenger side will NOT bolt up. I guess an owner could use the Pypes A body down pipe to tie into the factory exhaust.

 

[olds307 and 403]

On my 79 I lucked out and got the "buddy price" for a nice custom dual exhaust at a friend's shop. Can't beat that buddy price! I love it and I hope to slap some headers on because the factory logs suck. Then it'll be perfect.

What motor is in there?

 

[N3M3S1S]

What motor is in there?

Good ol' SBC. Probably like 300 crank horsepower, nothing super special.

 

[rogue_ryder]

Probably G body or maybe even A body, but don't look like in the bends for them. I would put money on Flowtech's header, poor fit, thin flange and rust even through the ceramic coating in no time. The Hedman long tubes are much better and the Hooker better again but are $600 once coated. Post pics of the Thorton shorties when you get them and put them on.

I think those old headers were for a firebird with the 403. The guy I bought this car from had a half dozen discobirds; but who knows...

The Thorntons bolted up fairly easily. They were nice enough to include gaskets and bolts BUT on each header 1 tube was blocking the bolt hole and I used a couple I took off which were shorter and had 3/8” heads vs 7/16”, so I could squeeze them in. Passenger side barely clears the top of the upper control arm on my car.

These headers are very nicely made. The welds are good and the chrome finish looks great. I’ve seen better but not at this price. Yeah the collectors are pretty tiny compared to the long tubes but these should flow plenty for a stock or mild small block.

Still waiting on my down pipes so I can’t say how they sound yet.


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