Ford Muscle Cars Tech Forum banner

1 - 5 of 5 Posts

·
Premium Member
Joined
·
2,216 Posts
Discussion Starter #1
It was determined from my measurements that I have been running with around a 9.4:1 compression in the hot rod. A .060 angle cut would result in 11 percent increase or 10.4xx close to 10.5 which is what I should have been running. That along with the massive port work I did and the improved valve angles should help quite a bit. My heads will take a max of a .060 flat mill so the shop does not expect to have to do a lot of supplemental work to keep the heads true. Whatever else is needed will be done including re-aligning the dowel pin and head bolt holes, re-facing the intake sides of the heads and chamfering the steam holes to match back up with the block.

I am going to get the heads back after the cuts and trial fit them anyway to check everything. This shop is one I have done business with before and I also know that they do a lot of dirt track engines. It is fairly popular with the dirt trackers to have their heads angle cut so this shop has done a lot of it. It isn't something they will have to learn on my set of heads.

They said I would only need to port match my intake manifold which I need to do anyways. We shall see.
 

·
Registered
Joined
·
10,299 Posts
Sounds like you're getting closer! :tup: When you do the intake, be sure to index it for position, and do a port match - not a gasket match.

David
 

·
Premium Member
Joined
·
2,216 Posts
Discussion Starter #3
Ok, index the intake for position. Are you talking about marking the intake alignment to head position once the intake is ported since there is some room for movement of the intake forward and back? After the intake is ported I could easily install it off again with ridges on every port if I don't put it back the way it was ported. Something like that?

No gasket matching the intake. I was going to stick the intake gaskets to the heads to have the proper port alignment and put a little vaseline around the port openings facing the intake manifold side. Placing the intake as long as I don't slide it back and forth would then leave traces that will show me how to mark the intake for porting. I can see a couple of the middle head ports down inside the Vic Jr which will help me with placing it. This is the only way I have determined that I can properly port the intake manifold to the heads and keep the alignment right.

Does that make sense or is this what you are talking about?
 

·
Registered
Joined
·
10,299 Posts
You have the idea, but what we used was direct port matching using templates that are indexed with pins. You also would use the index holes to install the intake for perfect alignment. To do this, you fully install the intake on the short block in the best position with the 'wiggle' room you have. Then use an angle drill and 1/8" bit through the intake flange and just into the head face between the ports - maybe 1/8" deep. Two index holes per head.

You can now use roll pins or music wire/welding rods to locate all 3 parts in perfect alignment every time. Remove the intake and replace the gasket with a blank made of poster board. Here is where different techniques are used by different folks.
A) Carbon the head and intake faces and reassemble to make a print on the blank. (Port blending)
B) Just align with the primary port (head dictates the port size and shape primarily) and cut-out the blank to match the ports. (Port matching)

Either way, you are crating an indexed pattern to remove or replace material on the intake with. Without going further, does that help with the concept?

David

[EDIT] PS: The index holes don't have to be perpendicular nor centered - just intersecting intake/gasket/head for alignment.
 

·
Registered
Joined
·
10,299 Posts
Pardon my clunky drawing, but this is the idea. Once the template is cut on the head face, it's transferred to the intake using the alignment pins, and the port mismatch becomes obvious. Mark and cut or fill where necessary to get both the port match from each intake runner to each head port, and a good blend up the runner to the plenum. When done matching, place the intake gasket on each part (using the alignment pins again) to see if trimming is necessary.

David

 
1 - 5 of 5 Posts
Top