I believe you just need to cut the center pieces off and turn them for the bolt holes to match the GM 3800 head then weld them back on in that position.
I looked at the exhaust manifold pics and I'm not actually impressed. Sure they seem about equal length, but, they are really short. Anything under about 22" for primary gives you a good top end but nothing in the bottom. In fact, it is almost like running open shorties. I think I'd fab my own before I'd use those. Just my .02
I know who fieroflyer is..... I just figured he would have posted. The length wasn't my primary concern it was the lack of a X-over i like. I was confused about what actually needed to be welded. My plan is to just run a Mustang manifold, stock manifold and dual glasspacks. When you have an m90 need to worry about low end.
[This message has been edited by goatnipples2002 (edited 10-07-2007).]
I found no problems running the Mustang manifold. I used one on the firewall side, as stated the center port needs to be cut turned then welded back on to line up. I ran 2.5" pipe from the manifold along the factory route under the engine where I "Y" the two sides together into a 3" inlet muffler. The stock 3800 manifold was cut off just after the EGR pipe and sealed off by welding a piece of steel over the opening. I have one sitting out in the garage that I can take some photos of if it will help explain every thing better. Dan
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10:41 AM
thismanyfieros Member
Posts: 3468 From: Red Deer, alberta,canada Registered: Dec 2002
gee Arn if they dont give much bottom end i wonder how i was able to spank a 454 chevelle SS last night in my poor ole unable to breath at bottom end 3.8sc.....boy was the owner of that car pissed at me..lol...tim
Well Tim I am glad to hear that lousy Mustang manifold I installed is not completely killing your bottom end power but at the same time I think racing your car does VIOLATE your warranty or is it only if you loose that your warranty is voided, never could figure that part out. In all seriousness such a loss in bottom end would not be noticeable with a manual tranny, with an auto tranny it may be more of a concern. Dan
Finally got some time do dig out the Mustang manifolds. The passenger's side manifold is a lot easier to work with and clears the block better but does not clear the A/C compressor so it is no good on A/C equiped cars. This one has already been modified to fit the 3800SC engine.
The center port has been cut and turned to line up before being welded back on. I tried putting a white line across the weld to show where it was cut.
The driver's needs to be bent upward to clear the block and starter which is a lot more work but it will clear the A/C compressor ok. This one is stock still only the two outer ports have had the bolt holes elongated for the GM 3800 head. You can see how the center port does not line up with the mounting holes.
The stock trunk side (on Fiero) manifold actually flows quite well on its own so I reused it but cutting off the portion that would have fed the crossover pipe. You can't see it on this one but I first welded some smaller pipe inside to help with flow before sealing the end with a piece of plate steel. Dan
Hmm, well I have a girlfriend wit ha 97 3.8l mustang that she keeps running into things, maybe she just need to hi something a little bigger so i can scrounge her headers
