head issues and how much to cut off the intake.

[Joseph24251_200]

I purchased a set of heads that seemed to have had no machine work done to them. I had them reserface, valve job, and new valves and spring put on. When I got them back from the machine shop I decided to check the cc on the head and found it to be 68-69 most where 69. Appears that theses heads had be cut before I purchased them. Now i'm tryin to figure out how much i need to cut off my intake manifold. Could anyone tell me how to measure how mucht to cut off the intake.

 

[416stroker]

I had the same issue when I put my Eddy heads on my small block. I found that my Air Gap intake was slightly to tall. The intake bolts would just start to grab but were to the top side of the hole. I knew something was up and didn't force them. I didn't even have the heads cut and still the intake would't fit right. I was told by Edelbrock that all castings are not exact and that in some cases the manifolds need to be cut. I was sure surprised to hear that. I ended up taking 0.40 off my intake to get the bolts to go in like they should. I also heard that this isn't all that uncommon on small block Chevies with aluminum heads. I had a shade tree mechanic tell me to "just elongate the holes" I THINK NOT! Machining it was the only way to go!

The odd part is that a friend of mine with the exact same setup put his intake on and it went on without any problems at all. As far as a way to measure exactly, I had to make a educated guess on the conservative side so if I need more I could do it. I suppose you could somehow use calipers and measure the difference in the holes center to center and go from there, but I'm not sure.

Anyway I hope it all works out for you.

Ron

 

[388dart]

I purchased a set of heads that seemed to have had no machine work done to them. I had them reserface, valve job, and new valves and spring put on. When I got them back from the machine shop I decided to check the cc on the head and found it to be 68-69 most where 69. Appears that theses heads had be cut before I purchased them. Now i'm tryin to figure out how much i need to cut off my intake manifold. Could anyone tell me how to measure how mucht to cut off the intake.

The intake bolts locating in the centre of the intake manifold holes is a good guide to go by. Do a pre-assembly with the heads bolted in place and the intake set in place with gasket. If the threaded holes in the head are nearer the bottom of the intake holes -you need a thinner gasket or some machining. If the threaded holes are nearer the top - you need a thicker gasket. most intake gaskets are .060" thick
Vector make a .040: thick and I believe SCE make a .030". Machining the intake makes the intake very "engine specific". - thus if need be I have the intake flange of the head machined.

I personally don't think you will have a problem with the 69cc heads. As for the machining of the intake - I've experienced the too wide affect on an Air-gap too.