uncle

I have a 1988 350 Block 14093638, with 14101083 heads. These are the ones with the center intake manifold bolts tapped at 72 degrees. Has anyone modified a 90 degree manifold for use with 72 degree heads. I see Edelbrock and others have manifolds with elongated holes and inserts. I want to try an use my manifold from a pre-86 SBC on this motor. Any ideas? I don't really want to buy a new manifold.

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geminifball

ya you can use the pre 87 manifold on newer heads. you have to elongate the threads or something like that. I personally don't know how to do it but I know it can be done. someone should really write up a how-to...

five7kid

uncle, welcome aboard thirdgen.org.

You elongate the mount bolt holes in the intake. Easiest method I've heard of (never having done it myself) is to use a drill and 3/8" drill bit, put the bit through the hole, and run it to the 72 degree angle (easiest to do with the drill underneath). This is with the manifold off the engine, of course.

You either need to find/make angled washers (I don't know of a source off hand), have the bolt head mount surfaces squared to the holes, or not worry about the lack of full contact between the bolt head and manifold.

Atilla the Fun

been there, done that. The holes still won't end up usable that way unless you use a pushrod-slot-elongating tool, then go back trough without the tool doing as five7kid suggested. Then, when you tighten down the bolts, grade 5 bolts will bend to match, grade 10.9s with hardened washers are the best option.

one92rs

i did it a different way. maybe the easy way out. i just slotted mine out.

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uncle

Thanks for the welcome, and the ideas as to how I can use my manifold. I apprecaite it!!

tony_cogliandro

easiest way is take it to a mcahing shop and they have a took to do it for about 40.00. that is what it costs to have it done, not the cost of the tool. and its perfect.