I’m looking for a set of Headers for my 1972 Cutlass Supreme, 350 olds motor. I have search online and even called Flowmaster/hooker/holley customer service. They said a Flowtech Part # 31100FLT may fit but the can’t guarantee they will. Does anyone know if they will in fact fit? Or can someone recommend a pair that will work. I’m looking to run 3” exhaust. Thank you

 

First off, ignore any warnings that say they won't fit a Cutlass Supreme. The Supreme is the same as a Cutlass S, F85, 442 for header fitment.

There are many headers available with varying price points, quality, finishes and fitments. Most seem to need at least a bit of "massaging" to clear frame protrusions. If you have the budget, American Racing Headers are reputed to be top of the line for fit and finish.

Thornton shorty headers are recommended by some, but they don't seem to provide much improvement over stock manifolds.

SBC headers won't work.

 

Why do you think you need 3" exhaust ? 2 1/2" exhaust should be fine. You'll need to find a reducer from the header collector size to exhaust pipe diameter.

 

^^^ This. For a 350, even 2.25 would be adequate.

 

I originally ordered 3” mufflers so that’s why I wanted the 3”, I found a set from Flowtech but there are 8 weeks out. I found that out today and ordered 2.5” mufflers. I canceled the Flowtech and have to wait 2-4 weeks for my refund, I ordered a set from JEGS that will be here this coming week. Just will have to return the 3” mufflers.
of course after I ordered the Headers from JEGS a buddy found a set from Oldsparts but I guess I’m going to give the JEGS a shot

 

I run Thornton shorties on the 350 roller that Mark (CutlassEFI) build me - I think they're ultimately better than the stock manifolds by some measure but probably not a lot - they do look a hell of a lot better though. Full headers will add performance over the shorties for sure, but if you ride on a relatively low suspension, driveways and speed bumps probably won't play nice with 'em.

And if you do opt for full headers, probably should plan for a mini-starter install as well to clear them with on the driver side. .

 

Isn't the starter on the passenger side?🤔

 

Nahhhh

 

Only if you have a Chebby or Buford motor.

 

Sanderson used to make a nice set of shorty headers for Olds but I just looked and apparently they discontinued them.

 

Maybe because they provided all of the cost and leaking gaskets of real headers with none of the pesky extra horsepower...

 

Could be and they were not cheap. Demand was probably low.

 

Hedman, they have a longstanding solid reputation of fitment and quality. https://www.hedman.com/product-detai...bhbSfuoYWYLYgA

Real headers not shorties almost always need some sort of modification in order to fit. Part of the game. Post #3 to #6 here, https://classicoldsmobile.com/forums...headers-89241/

If interested in power gain difference between long tube and shorties, here from our resident and premier engine builder CutlassEfi. https://classicoldsmobile.com/forums...eaders-177221/

Built Olds 350 dyno proven. Below are peaks for both options.

Long Tube = 422.6 hp @ 5500 rpm
Shorties__ = 399.3 hp @ 5400 rpm