I built a new engine for my f-250 4x4. The truck had headers on it that were junk so I decided to replace the headers with stock manifolds. Motor is a stock build. The problem that I am running into is the collector on the end of the pipes that hook to the manifold. I got a pair of pipes from another similar F-250 5.8 truck. Not sure exact year but same body style as my 91. The donor truck was also a 2wd. The problem that I have ran into is the flanges on the end of the pipes. The bolt holes are too narrow. They are approx a bolt width too narrow on each side. http://www.summitracing.com/parts/wlk-40585/overview/ This is a set of pipes that I found. Will these hook to my new exhaust manifolds. The manifolds were ordered for the 91 truck. I have double checked the part numbers and the information on the box. Is there a difference in the bolt spread on some of the 5.8s between the year models. I would hate to spend the money to buy the new pipes and them still not fit.

 

OK, got in a new H pipe made by Walker. It is a exact replacement for the 91 F-250 E4OD 4x4 with the 5.8. It has the same flanges on it as the ones I got from the junk yard. Has anyon else ran into after market manifolds with the wrong spacing on the flange bolts. The flange holes are approx 3.875" apart (3 7/8").

 

The Bassani y-pipe I used on my old 1992 F350 w/5.8L engine fit like a glove. Perhaps the supplier shipped you manifolds for a 5.0L engine? The first Bassani pipe they shipped me was for a 5.0L equipped truck. The part number on the box was correct but it was very obvious the pipe inside was wrong.

 

Thanks for the responce. I am seriously wondering if the bolt on the collector end of the manifold are not off a little. The truck had a junky old set of headers that were rusty and wouldnt seal off so I decided to junk them and got back to stock manifolds. I went to the junk yard and got an H pipe off of another F-250 with a 5.8 in the same body style (87-92). The flanges on the collector end had narrower bolt holes as does the new manifolds. According to the numbers on the box they are for the 88-92 F250 5.8.

 

I have run into this with my 86. Make sure your studs arent bent first. If you go to NAPA and look in the back of the walker BOOK, they give the specs on flanges, you should be able to find one with the proper bolt center dimension and pipe diameter.