Ok here’s what I got, measured intake and James it’s the same as your stock one.
I thought I had 2 w motor distributors And a SBC. I have one w and 2 SBC. I was using the 2 SBC which are the same. Thinking one was W. “rookie as Don calls me” I found the W motor one and stuck it in the hole first picture and fits as supposed to.
second picture is the difference in length of the W and the SBC. Approx 1/2 inch
The next picture is the sleeve in the hole
Next is the sleeve and the collar clamp. The sleeve sticks up a bit From the collar and the rise from the intake flange and the top of the sleeve is exactly the difference in length from W to SBC
Last pic is the SBC in the sleeve with the collar. There’s a bit of space because I didn’t want to jam the sleeve on that old test dist but normally the sleeve would go all the way on
Still needs shims and gaskets as first thought but the sleeve from show cars is accurate and right according to the length of the SBC distributor.
John, the oil pump shaft is 409 which it needs to be to make this work.
With everything in the way it’s supposed to be the dist is snug and doesn’t move around