Howdy, I am working on rebuilding a 1972 455 engine to drop into a 1964 frame. We bought an Edelbrock intake manifold and the bolt holes are not lining up.  Should we look at making the bolt holes bigger in the intake manifold or would loosening the head bolts give us any additional wiggle room to work with?

I've had this issue before and tried to fix it the wrong way, by enlarging the bolt holes. The problem when you do that is the intake runners are not left matching the head ports and flow suffers. It may also leak. I found that my block had been decked and my heads cut to straighten everything out in my last rebuild. The solution is to have the manifold cut to allow it to fit properly. There is a chart that shows how much to cut off the intake based on how much was cut off the rest. I'll see if I can find the chart. Unless you had that motor since new, and its never been apart would you know if a critical dimension has changed? Head gasket change could even cause issues.

Check out this. http://www.wallaceracing.com/calc-intake-mill.php

 

Thank you.  Yes we chatted about enlarging the holes but we were a 1/4 inch off and that was too much for an adjustment.  Turns out our Valley Pan was getting in the way of the Intake Manifold. So hoping that we can adjust the Valley Pan enough to seat the intake manifold. Fingers crossed.  

It is a continuous learning process..........

Cheers~
JA

 

What intake are you using?

Edelbrock Performer.

On 10/2/2018 at 11:45 PM, 64GoatGirl said:

Thank you.  Yes we chatted about enlarging the holes but we were a 1/4 inch off and that was too much for an adjustment.  Turns out our Valley Pan was getting in the way of the Intake Manifold. So hoping that we can adjust the Valley Pan enough to seat the intake manifold. Fingers crossed.  

FYI...  Unless you're doing it to save weight, that Performer is not going to "out perform" the factory cast iron manifold, especially on a 455 that normally won't see the north side of 5000 rpm often.  You might spend some time looking at Cliff Ruggle's (QJet master) and the real world testing he has done.  Here's a link to a post he wrote on his web site:
https://cliffshighperformance.com/simplemachinesforum/index.php/topic,511.msg2231.html#msg2231

Bear