65 273 Intake manifold

[volaredon]

A pic would be nice-
Is it like this?
View attachment 1715885660
If so, you've already got an aftermarket (Edelbrock) 4bbl. manifold, if you have a 2bbl carb on it, it must be using some kind of an adapter plate.
View attachment 1715885661
And if you do have the 5/16 intake bolts, it must have been modded already...?
A factory manifold would be cast iron, an SP2P is aluminum.

they made the SP-2P as a 2 barrel version as well, if Im remembering right. I had a 4 bbl one on my Diplomat and remember something about a 2 bbl version back when I got the one I used to have.

 

[volaredon]

and.... I remember having had a set of magnum heads drilled at a (non automotive) machine shop years ago so I could use an LA intake manifold on it. The Magnum heads also had 5/16" bolt threads as used from the factory applications. I brought them a manifold gasket and told them to drill and tap perpendicular to the intake mounting face.
They did as I said/ and when I went to bolt it up, I found out that the LA's newer than 66, still aren't straight perpendicular. I snugged up an LA manifold to these newly drilled heads and discovered that the captured washer only touched the intake on one side of the bolt. I don't remember how I figured out the exact angle needed, but I remember it being 7-1/2* off, from being exactly perpendicular to the manifold mounting face.... I was gonna have to get some tapered spacer washers made, to be able to run those heads as I had had them drilled out. I ended up using those heads on a different Magnum engine, with a magnum beer barrel intake/ as they were originally designed for. Instead of the LA engine, that I originally planned to use them on.