Thread: TBI intake manifold, distributor hole too big

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I am putting TBI on a 1985 SBC. The TBI intake manifold has a larger hole for the distributor than my old carborator manifold has. Why is the hole so big? I have the newer HEI large cap distributor.

Is there an adapter or something I can get for this? The hole is almost big enough, not quite, to allow the distributor to slip right thru it.

Thanks,

Tom

If you're using the TBI, you'll need the proper computerised distributor anyway.

The intake manifold is probably from a 1991-1993 Caprice, or Roadmaster or Olds Custom Cruiser. Those cars used TBI but they also had excessively large cowl overhangs that extended over the area of the distributor. The factory had to oversize the distributor hole in the intake to allow removal/replacement with the intake still mounted on the engine.

That intake can still be used but you need a distributor from any 1991-1993 fullsize GM car with a v6 or v8. OR you need a different TBI intake from an Fcar or from a C/K/G truck/van that had TBI.

See also this thread:

http://thirdgen.org/techbb2/showthre...butor+hole+TBI

HTH.

The center bolt holes on my TBI intake manifold for a SBC dont line up with my heads, they are offset.

I have searched on the web and have seen it said that these holes can be drilled out and elongated to work and large washers put on the bolts.

Is this my only alternative?

Only alternative? No.

You could buy an intake specifically intended for a pre-1987 sbc, so that the bolt holes would match.

You could have the manifold you already own welded and then redrilled for the proper bolt hole angle.

You could do as the web suggested (use a round file make the holes oval) and then use large washers to make up for the gaps. You could also use angled washers such as those sold by Summit, and/or by McMaster Carr (an inductrial supply company).

Thanks for the replies, I went back to the junkyd this afternoon and got the manifold with the right size dist hole, I will elongate the bolt holes as you suggested.