Thread: Edelbrock Manifold

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I have an Edelbrock Air Gap manifold I'd like to use on my Chev 350, however the distributor hole is larger, so the distributor is a little sloppy when dropped in.. Is there a reason this hole is larger and is there a bushing for this?

Welcome to CHR Turbonator, glad you're here. I didn't know it, but ran across this old post that makes it sound like it's common practice for the distributor hole to be oversized - Link to 2006 post Distributor bushing for intake manifold
Also, it looks like JEGS sells a bushing kit, designed to deal with milled heads, etc dropping the distributor too low, but it also mentions the over-sized hole - JEGS Distributor Shim and Bushing Kit - Free Shipping on All Orders @ JEGS

Maybe one of the other guys can shed some more light on the best way to solve the problem. I'd probably call Edelbrock and see what they say. I bet you won't be the first to call them with this question, and it would be interesting to hear what they have to say.

What is the part number of the manifold?

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All chevy distributors fit all the v8s-------small block, big block, tall deck, short deck
You get into those corners or out on the point when you use standard deck manifolds on tall deck blocks, mill block/head decks to adjust piston squish, tall deck manifolds on short blocks, etc--------


The aftermarket manifolds are probably a little bigger to allow for the moving around to line up ports, uneven tightening of bolts, etc---------it is important that the dist lower end fit the block snuggly in that oil gallery and at the proper height for the correct gear mesh with the camgear ---------

Jerry, the way I read Turbonator's post he's saying that the big hole machined in the back of the manifold to seat the distributor is machined larger than the corresponding dimension on the distributor shaft. I pointed out the JEG's bushing & shim set because the description also mentioned oversized distributor holes "...common to many aftermarket manifolds." Maybe I read it wrong.... I went out and pulled the HEI distributor and the hole in my manifold measures 1.3875" and the boss at he bottom of the distributor measures 1.20", a difference of 0.1875" or 3/16". Looks to me like the machined boss down towards the bottom of the distributor case, just above the drive gear, accomplishes the alignment, and once locked down on top the side clearance is not a big deal? Again, maybe I read it wrong.

Yep-that's the way it works

OK, this brings a question to my mind now. Let's say, just for talking purposes, that we have an engine that's had the block align bored, then decks cleaned up maybe 0.020" to bring them to spec, and then the heads milled 0.040 to get the squish just right. Now, the intake has been milled to get it sitting right, relative to the head surfaces and the "China Walls" of the block. This means that the mounting surface for the distributor has dropped a bit.

What's the procedure to ensure that the distributor drive gear and the cam gear are properly engaged for maximum life expectancy? That is, how does one decide on the right shim stack beneath the distributor, or is it not that critical, considering that the distributor normally has a rough gasket there anyway?

You don't want to bottom out on the oil pump drive, you want to be in the middle range of the gear

You can use red lead to verify gear mesh, add or remove shims til lead reads correct..

I keep a tube of white oil paint fron art stores