I'm getting to the point where I will need to port match the heads to the intake manifold. My heads are aluminum assembled heads.
When I start porting should I remove the valves to make sure I get all aluminum particles cleaned out when I'm done or can the valves stay in and just blow the ports out really well when done?

 

I'd remove the valves.

 

Thought of another question on port matching. What exactly is gained if the intake manifold is smaller than the head port in both width and height.
I've read about fuel dropout on the down side from the sudden increase in volume, it wasn't explained why, but i can guess it's due to a reduction in pressure and velocity, is that all of it?

 

usually the intake port is smaller then the head port,so enlarge and match the intake port to match the head port.you can make a template of the heads ports and scribe them onto the intake.no need to remove valves if you are just porting the intake.

 

There's not much to be gained by port matching your heads, but if you decide to do it, disassemble the heads. Aluminum shavings aren't something you want in the engine.

 

Whatever you do, don't match the ports or intake to the gasket. The gasket will be larger than either - a better approach is to make the intake runner the same size (or slightly smaller) than the port of the head. If you find that the head needs to be enlarged a bit to match the intake runner, that's ok.

 

I'm kinda leaning towards not porting them at all. I did have the heads shaved .030" so they sit a little lower than they would have otherwise. I'll need to figure a way out to see if the top of the port on the heads will be a problem. Mocking it up the intake sits well on the heads but of course I can't see how the ports line up. Tape on the heads and some die around the intake ports maybe?
If the intake ports are smaller that should be good as a reversion dam?

 

I make a cardboard pattern that used the two outside holes in the heads as a reference. Cut out the ports then use the template to black the areas that needed material removed on the intake. I had to take a lot. Here are some pictures.

 

Once the intake is ported to match the size of the head ports how do you insure that alignment of the ports is correct for installation? The bolt holes allow for a fair amount of movement. I can see how the ports could be the same size but misaligned during installation which would undo much of your effort. Seems like some kind of alignment pin/s would help keep things straight.

I want to block off the crossover heat also. I've read that the gasket will get eaten through over time. So to keep this from happening would a small piece of sheet metal and some rtv to seal things up suffice?

 

If you use reference points like the bolt holes, they'll line up. You can the use a bore scope to check them.

 

That is what I did. When installing I visually checked the outer intake bolt holes were centered with the head holes. just start the bolts and look at the centering in the intake bolt hole. Mine lined up fine on the above build with a .32 cut on the head decks. As you can see I had to port mine as there was a big difference.

 

Yesss a bore scope. Cool tool. I've been looking for an excuse to buy one this is just the occasion.

Sounds good I'll give er a shot. The bore scope though.... I like that.

 

When you snug thebolts up it should center itself...or be awful close.

 

This port matching thing is not the best idea if your manifold port is smaller than the head. If the head port is smaller then by all means match them match. The step at the manifold assuming the manifold is smaller is a good thing as it acts to stall the reversing air flow cause by cam overlap to stop right there as opposed to going all the way up into the carb and messing the single up in the carb causing mixture problems.

 

If the manifold port is smaller than the heads, then doesn't the pressure drop cause fuel to separate from the air fuel mixture by changing the temperature at the same time?

 

nobody has mentioned gasket numbers.... port it to the correct gasket felpro gasket... they are numbered so you get the correct size every time....

 

Yes, I think on a street driven car with any kind of overlap on the cam and mine is 54*,and spends most of it's time below 4000 rpm or so this is a good idea. I was waiting for someone else to suggest it as well. Thanks Manuel.

As I understand it the reversion of air, if it makes it all the way up to the carb, will actually pull a little fuel from the jet and then when the air reverses and resumes the right direction it will once again pull fuel. This creates some difficult tuning conditions since at low rpm the reversion may reach the carb and at higher rpms it may not. Like I said as I understand it not experienced it yet.

I looked through all of summit's offerings for intake gaskets and didn't find any that were the same size as the intake or the head.

I have read that too. Don't know if there is any evidence to support that or not. Given the choice however I would rather control the reversion and risk the fuel drop out.

 

Iirc it's call Boyles law. As for the intake gasket the head manufacturer should have a recommended gasket to match port size.

 

The ONLY effective way to a true 'Port-Match".

1-Have heads pre-mounted on block to be used, with both head gaskets in place.

2-Use 2 pieces of masking tape or 2 spots of silicone and position intake gaskets in place.

3-At this point make sure the intake gaskets (marked R/L) fit the head ports the way you want them.

4-Lay the intake in place with 4 corner bolts, at this time you'll know if bolt location is OK.

5-Snug the bolts down, and using a 1/8" drill, drill 4 holes (1 at each corner) through the intake making sure where you drill you will hit the gasket (don't drill where there is no gasket below).

6-Let the drill tip pass right through the gasket and stop on the head. Remove the intake and lay the gaskets on the respective sides as templates, we use 1/8" "cleco" buttons to mount the gaskets back on the intake sides, you can use (2) 1/8" drill bits for alignment. With the gaskets mounted on the intake, simply scribe out the ports on the intake and "grind away".

By using this method we can literally leave a perfect "overhang" (reversion-wall) on the intake runner of .020"/.030". In simpler terms, the head port is slightly larger than the intake port.

It's your choice to line up the port perfectly or leave the "overhang".

The entire procedure takes about 20/30 minutes to achieve and guarantees a "perfect" fit on the final ***’y. This procedure can be done on assembled long blocks that have been running and getting an intake change. We run the intake port "inside" the head port for anti-reversion only on street engines and not on "track only" motors due to the higher VE of race prepared engines.

Thanks, Gary in N.Y.

P.S. There is no other accurate way (that I'm aware of after 41+ years of engine building) to get "perfect" port alignment, period!

 

Template method, per 63mako.



...and port matching does NOT involve opening intake and head ports up to the gasket.


.