CrazyHawaiian

I was wondering if anyone knows anywhere that sells the correct size/angle shims to bolt an 87+ TPI Intake Manifold onto an older Small Block Chevy Engine (pre 87). I know the difference is the 4 middle bolt angles, 73 degrees versus 90 degrees. People have mentioned re-drilling the heads for the correct bolt angles, this is not the route I want to go, I want backwards compatability. I want to go the route of shims and longer bolts. People have mentioned this before but I don't have any specific info. The shims would need to be the correct angle for the bolt heads to sit flat. does anyone happen to have any specific info on doing this? Or maybe a place that can make or happens to stock the correct shims? Thank you!!

rdaggett

I would like to know as well

CrazyHawaiian

Holley makes an adapter kit with 4 shims and bolts but its advertised to allow you to use older (pre 87) Intake manifolds on newer (87+) heads. So its kind of the opposite of what I'm trying to do here. Here is a link to the conversion kit on Summit's website

http://store.summitracing.com/partde...8&autoview=sku

You guys think those shims could also be used to do what I'm trying? 87+ Intake Manifold on pre 87 Heads?

Boosted_SS

actually i would simply redrill the holes on the intake. if i'm not mistaken it is the bolt at the four corners that are at a different angle. i did this with my intake and i have had no problems what so ever. i simply ovaled out the holes in question and it works great! i have it on a 383tpi pushin over 500 whp. so it should handle what you can put down.

Dilbert

The manifold bolt holes are easy to modify.Only the TWO inside most bolt holes need to be modified.Two holes on each side of the manifold and you're done.Then the manifold will fit EITHER head style.I did mine on a DRILL PRESS.Very easy to do.

Jaxom

The shims from that Holley kit should work since you're making the same 17* angle change no matter which way you go, but I think the bolts will be a little long. You'll still have to drill the intake no matter what you do.

ironleg

or just get a 86 tpi intake thats what im doing 86 intake on 72 heads

CrazyHawaiian

Thanks for the replies guys. I tried to find the earlier style Base both locally and E-bay, so far no luck (outbid twice on Ebay). I do have an extra 87+ base so lately I've been considering just modifying this extra Base like you guys are saying. Do you guys think I could do it with a Dremel tool? All I need to do is take off some material around those bolt holes so the head of the screw sits flat right?

xbuckeye

I ran into this last week. I'm putting a 87/88 tpi manifold on a 85 motor.
The 4 center bolts have to be longated. A dremel was tough going, so I work in a machine shop, I sat it on a mill and slotted the holes. I did not need the shims because I milled the area where the bolts tighten down on. A mechanic told me that these ports are exhaust ports which makes me feel better about what I had to do. I am checking for leaks today.

Boosted_SS

i did this 3 years ago to my motor and i have had no problems what so ever.

Vader

You could use self-centering ball-cup washers for the bolts. This has been discussed about 100 times before. Searching the archives, you can probably even find the part numbers I've posted, although the prices may be a bit outdated.

Vader

Holley/Weiand 90748:

80Sierra

You have a pm