Are the exhaust bolt patterns &/or port layout the same on a 350 vs. 340? I saw a place that sold shorty headers for 340's and was wondering if they'd fit or could be modified for a 350 unless someone makes them for 350's, which I've never seen.
I do have 10 sets of 350 flanges so if a person wanted to they could buy a set of Chevy short headers to modify to fit the buick flanges.
Thanks - May take you up on that offer. Was going to post at some point as my builds get closer to see if there would be any interest in 350 shorty headers. I don't know if the performance gain would be worth it but not sure that I want to run long tube headers (does this mean I'm getting old, lol?). Also been thinking about building one of my GS 350's as a stock appearing (F.A.S.T.) 350 car as well and seeing what could be done there with respect to performance.
These Chevelle headers might be the ticket, would need stainless flanges. Small Block Chevy 283 305 350 400 Stainless Headers Chevelle Malibu Camaro Monte | eBay
TA has them: http://www.taperformance.com/products.asp?cat=385 Not shorty's though, but I don't believe there is much gain in shorty's over stock. Also, I don't think FAST rules allow headers: "4.01 Cast iron exhaust manifolds are mandatory and must be correct*, have correct* casting numbers and be of correct* material. Under no circumstances will headers be allowed, including those cars that had headers delivered in the trunk. Internal modifications are OK. Correct* appearing exhaust manifold paint or coatings are OK. Casting date codes are not looked at and are not part of the tech process."
Tom miller did a 11:1 engine with a TA 212 cam and stock manifolds for a FAST setup and it worked really well. I can’t remember the 1/4 times but it was very good. yes Ta has the headers flanges but mine are $40
Here is the car I was talking about: https://www.v8buick.com/index.php?t...0-powered-1969-buick-special-2dr-post.323244/
That's the real question here - Would be shorty headers provide any increase in performance & if so how much. We might need to find out. Thanks - I was aware of that. I have two (2) 350 GS's & was thinking of maybe making one stock appearing. IIRC @Tom Miller ran high 12's with a 4.?? (.56 or .88 I think) rear & said the car wasn't really streetable - Maybe he'll chime in here with some details of what it ran & what he did to get it to that level. I should probably get a pair of your flanges. I have a set of TA headers and planning on dialing in a couple of m/l stock (#'s matching) engines for the the GS's in a Skylark test mule (have 2 other engines to subsequently build for the cars) and could maybe experiment between std. iron, ported iron, shorty, and long tube headers. Maybe it won't make much difference on a stock engine. Idk.
The reason long tube headers have a tube length of around 32" is because that's what it takes to have suction at the port the next time the valve opens. So you should see a significant boost over shorties. It also makes a difference if they are equal length tubes. Many production headers can have deviations of up to +_ 2" in tube length. Since shorties cannot generate port suction they are only a little better than cast manifolds, based completely on flow smoothing. Jim
