Center dump exhaust manifolds circa 1975

[FERoadster]

I've got a few sets of them and looking at them they seen like they would flow better than the log manifolds.
Unfortuntantly Jay in his book doesn't test these.
So a "What if question" ??  Take 2 of the center dump (factory was one center and one log)  and use them together reversing the outlet of one so both were rear facing.
Would they improve performance over 2 log exhaust manifolds?  An easy fix to just cut rotate and weld CI outlets (if you know how to weld CI of course).

JUst a thought  FERoadster

[GJCAT427]

Actually I did use a set of FT center dumps. I welded up the crossover ports and went to use them on a 56 C600 I`m building with a 390. Haven't got around to using them yet but I don`t fore see any clearance issues. The smaller truck chassie may pose some problems, but think you could make them work.

[Dumpling]

Why would you need to cut and weld one side?  Just a longer tube on that side (maybe a matching shorter tube on the other)?

[FERoadster]

Turning the outlet around on the passengers side would make it point to the rear. Otherwise you would need a U bend. Also these are the PU exhaust manifolds not the FT's.
Richard

[jayb]

I was actually looking for a set of those to test when I was doing my book.  I did find an FT set but wasn't able to make them work, so I never got a chance to see how they would do.  My guess is not much better than the log manifolds, but probably a little better...

[Rory428]

And likely nowhere near as well as a pair of headers. I had a pair of Hedman long tube headers on my 74 F350 car hauler, and even with a basically stock low compression 390 4 barrel engine from a 75 F250, the change from those exhaust manifolds to the headers, and dual exhaust was very noticable, both in performance and MPG. I think the main reason the late FE PU trucks used those ribbed exhaust manifolds, was to reduce the problem of cracking. My truck was almost always over 10000 pounds when I drove it, and in the first 3 years I had the truck, I had 3 exhaust manifolds crack, 2 lefts and 1 right.

[TomP]

The only FE I've seen make any power with those things had them mounted upside down (I think hat blocks the FT crossover) and had turbos mounted on the outlets.
 That was a mud racer in the 80's. I think Bob still has it too.

[chris401]

I've got a few sets of them and looking at them they seen like they would flow better than the log manifolds.
Unfortuntantly Jay in his book doesn't test these.
So a "What if question" ??  Take 2 of the center dump (factory was one center and one log)  and use them together reversing the outlet of one so both were rear facing.
Would they improve performance over 2 log exhaust manifolds?  An easy fix to just cut rotate and weld CI outlets (if you know how to weld CI of course).

JUst a thought  FERoadster

I think two of those pickup manifolds would work better than logs. I have not measured the exact volume but they are larger inside. Years ago I mocked up a left ribbed manifold on the right side of my 65 F-100. I tacked together an angled spacer to reverse the exit but could not make the flange clear enough for the exhaust pipe. I to was tired of leaking headers and cracked manifolds.

More recently I mocked up an FT center dump on the passenger side of an F-250. With the engine perch moved to the forward position and engine mount on a plate it looks like there is enough room to bend the 2.25" pipe enough to clear the cross member and frame. The FT ports are the early higher location but if flipped upside down like TomP mentioned the are a match to the late model heads.

[TomP]

When you flip them upside down the outlet aims to the side, not upward. That worked on a mud racer with the engine moved and nothing beside it. A really sharp bend on the exhaust would negate any gain from the better flowing manifold.

[machoneman]

I wonder if shorty steel tube headers, if long tube headers aren't in your plans, would be much better. 

https://www.summitracing.com/search/part-type/headers/make/ford/engine-size/6-4l-390

[FERoadster]

I've got many sets of shorty PU headers and a few sets of medium and long PU and car headers also a set of the Sanderson block huggers.
This was just a question of What If. I don't want to throw them away so they will go into a pile of other exhaust manifolds.

Richard