I have a 386 with forged internals and aluminum trick flow heads. They are nothing special, but they work. Then I have an edel Vic. jr. intake and a N20 plate, 1" spacer and a 750 Holly DP. I also have hooker 2210s, and a 4" catback with 3" Y.... blah, blah, blah...

So with all that said, nothing of port matched or anything. Is it worth spending the extra $ to have the intake taken off and ported to match the heads and so on? What about the spacer and exhaust ports?

People say they have, but never really report back posting gains of if it was worth it. I can lay down 350 HP and TQ with my stock type ignition, I have since added a MSD pro billlet dizzy, digital 6 plus box, and a blaster coil. Car def. feels faster, would it be worth getting all that porting done? I want to try and get 400 HP at the wheels but don't wanna have to make 2 trips to the dyno.

Anyways, thanks for any insight.

Later

-Dennis

 

The biggest problem comes when the intake ports in the manifold are bigger than the ports in the head. That "wall" creates turbulence that kills flow.

If the ports in the head are bigger than the ports of the manifold, you won't see much gain with gasket matching.

 

I do it to any engine I ever have the heads or intake off of. I always seem to notice a smoother "pull" from low to high rpms and it seems to idle slightly better.

Maybe it's in my head, but I'm sure I feel something...

 

There is a lot more to it than "gasket matching". What and where is the smallest cross sectional area in your head? What and where is the smallest cross secional area in the intake manifold? What cross sectional area in the intake manifold will work best for your motor?

These are things you need to find out. You want the intake manifold runners to act like a funnel. Regarding the one inch spacer only the dyno can tell you if your combination likes it. It would be worth it to get things "right" regarding the total intake tract.

 

Thanks for the repiles. I hadn't thought of the "wall" situation. I will look into it next time I pull the carb, (at the dyno) I will be testing 4 different spacer combos. 0.5, 1, 1.5 and 2" spacers. Should be fun to see the results.

in the end, the car is just a crazy street car. Chances are I won't take it to the track more than a couple times a year. So maybe I will wait a year or two to rip the intake off to do port maching and so on. Kinda sounds like a lot of work for a car that I drive to work and is allready going to be making almost 400 RWHP

 

On a 9 second car I knew of, port-matching the intake manifold to the heads was worth 2 tenths and 4 mph. But there was a big mismatch there to begin with.

 

Damn! Well that makes me feel better. Since I think if I drove that 9 second car around on the street, I would never feel the difference of ported or not, so that makes it even less likely I would feel it on my car. Thanks for the insight.

I will hold off for a few years.

 

It is usually the LEAST productive part of port work.

It gets results ONLY IF all other port work has been done, and the last remaining restriction is the port situation. The most important part of port work is the bowl; and in stock heads, especially the place where the valve throat cut fails to blend into the bowl casting; followed by the guide; followed by the "common wall" (head bolt) side of the port. Unfortunately most backyard head porters can SEE it, and fail to realize that the things about the head that YOU CAN'T SEE are more important, and they waste a bunch of time on it.

One bad thing that can happen, if using an inappropriate gasket, is "hogging out" the port so big, that you basically create this extra little plenum out there in the middle of the port. Ideally, the port should be of uniform cross-section all the way down, and slightly decreasing in area as you move from the carb to the valve, if anything; but "gasket matching" often creates this big "bulb" sort of chamber in there, which promotes fuel separation out of the mixture because of the sudden decrease in velocity.

 

Wow. great info. I guess I will really hold off on it till I get a few books on the subject and learn more. Still seems like a good idea if I wasn't doing the work. My heads are CNC ported so I think they flow pretty well now so no bog rush.

I just know in a few years I am gonna be hungary for more HP and am playing with ideas as to how I can get more out of this, or if i am just gonna save up a crap load of $ and get an FI GM big block. Those are sweet motors.