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I was wondering what size diameter pipe I should have for a single out? Or if dual, what size? Does anyone have any pictures of either setup? How should I run the pipes? How much more in performance can I realistically expect from this type of upgrade?
Also, I'm using the stock cast iron manifolds on my truck. I can cut and weld pipe all day but I cannot justify the cost of headers right now.
I acutally went to NAPA a few years ago and bought a complete system for my '77 shortbed with a 400. Not much to it, a "y" pipe to bring both sides to the inside of the right frame rail, the muffler, and then the tail pipe to exit behind the right rear tire. Mines an F150 4X4 so no cat is required.
The only thing that has been done to it are those ideas suggested by Bubba - his website (man it's amazing what a good tune up and a little tweaking can do).
I'm running stock manifolds with 2 1/4" duals, turbo mufflers on my 78 bronco. Stock 400 and it works well.
My 79 250 with a slightly modified 400 has headers, flowmasters and 2 1/2" duals. Works very well and sounds good too
Don't go any biger than 2 1/4" duals or 3" single pipe.
I have always liked the dual exhaust that exits right in front of the rear tires, thats ford style, or the ones that exit at the rear quarter panel, corvette style.
I would suggest that if you tow anything, or do a lot of close backing up, that the bumper exit pipes are not a good idea.
I would start with a good set of headers. Follow it up with some free flowing exhaust pipe 2 1/4"-2 1/2" works good with the 351M/400. Mufflers are your choice, Most will help with sound control, and give you some extra ponies. Finish that exhaust system with some nice stainless steel tips, and you should be done. Here is the system that I am running on my 1978 F-100 Custom with a built 400 V8.
I know this doesnt match your engine....but on their web site it doesnt give all the products. It's the same price, I was looking at it for my truck, 77 f150 w/400. It'll give you an idea, or maybe order the catalog.