OK guys,

Not only did you all not have a part number, no supplier did either, for a 4 hole riser to adapt the Offy manifold to a Holley or Eddy squarebore. I had been using a Mr. Gasket 3/4 inch GM spreadbore plate drilled to the Offy pattern but decided to go to 4 separate throat holes from carb top to interior of manifold, about 5 inches of downdraft.

So, not finding a nice 3 inch thick aluminum billet readily available I got a 1 inch aluminum plate 8 inches by 8 inches from the McMaster Carr cartalog, set the old Mr. Gasket GM spreadbore adapter on it for a pattern and drilled away. I set a 2 inch riser with the swirl groove milled inside the throat on top of the 1 iinch and picked up the swirl and milled it into the 1 inch. The 8 x 8 adapter fits neatly over the Offy intake but needs to be offset so that only 1 inch of it extends past the driver side to let throttle levers clear.

Then, as Slant Six Dan has opined, because aluminum conducts heat so well why use it for a heat shield, I got a 8 inch by 24 inch piece of 1/8 inch gasket material (usually used for making your own head gaskets) cut a hole in it to allow for the carb 4 hole gasket, set a 12 inch long by 8 inch wide piece of it over the intake manifold for a heat shield, and bolted the 1 inch riser onto it. I used stainless allen head bolts to tie the 1 inch to the manifold. I did ths by counterboring the 4 holes on 3 7/8 centers to accept the allen heads to the intake manifold. Then the next level of 2 inch riser could set on flush on a 4 hole gasket on top of the 1 incher and be attached using stainless studs at its outer holes (on the corners) to the 1 inch riser.

Nothing but a simple drilling and milling task, but it sure makes me wonder why, if a spreadbore open hole adapter can be had (and drilled to fit an Offy) why a 4 hole adapter is not available. Is everyone using risers doing so by dumping from a throttle bore into an open hole in the case of the square hole adapter, or into a modified hole in the case of the spreadbore adapter? Why did I use aluminum...I just don't trust wood and plastic, as neat as they look.

Love those slants!
rock
'64D100

Mr. Gasket makes a 4 hole spacer that you can drill for the Offy and bolt on. I just did an Offy for a buddy that had one on it.

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Official Cookie and Mater Tormentor.

there is a local man here that works on carbs for different circle track racers around my area that had an idea for a carb spacer that is different. He brought a carb spacer made of wood to the shop. He wouldnt say what type of wood it was but it was lite. Real lite like maybe it was balsa. It was sealed with some silver colored material that, to me, looked like paint. He also had some real lite weight studs made from a material he wouldnt identify except to say it wouldnt conduct heat and it was used in the space program. It looked and felt like teflon and,sure enough, if you look for it you can find teflon rods in various thicknesses. It was a carb adaptor, carb spacer and heat shield all in one. One guy tried it out but it was sucking air. I don't know if he ever got it straightened out, but if he did, then I guess it was a good idea. Anyone ever heard of such a thing?

Wooden spacers are usually made of oak or maple so there is a good sealing surface. Anything soft will compress and leak vacuum. Wood spacers were the hot ticket before phenolics got popular, and I think Moroso still makes one.

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Official Cookie and Mater Tormentor.

Thanks 'zilla and gothers for commenting,

In my July 7 post no one came up with a Mr. Gasket part number, and my rpretty good local speed shop couldn't find a 4 hole in a catalog regardless of maker. I have seen them on ebay and as you say, you saw one recently....but maybe they stopped making the 4 hole one.

Also, I never was able to find if the "old" one had 1 7/16 holes like the Holley 8007 and Eddy 1404 plates. I know the 1 1/2 and the Quadrajet ones were made, but the 1 7/16 seems proverbially scarce. And of course other than the the $42 the aluminum billet cost, the price to get exactly what I wanted was ok. Woulda' been nice to get one used for $15 though!

Thanks,
rock
'64D100