Gasket Matching Opinions Wanted

[emorrison96]

Hey guys, looking for an opinion on whether or not to gasket match my heads and intake.  I feel like I should know the answer to this but my engine building experience so far has been pretty much bolt together affairs so I want to consult the experts before spending money or time and effort that might be detrimental to my goal in the first place.  Basically I'm building a 427 (stock bore and stroke) with edelbrock medium rise heads and a BBM tunnel wedge intake.  For fuel delivery I'll be using a FAST or equivalent 2x4 fuel injection setup.  I know that the intake I'm using is large for my cubic inches.  That being said, the intake ports on the heads and intake match absolutely perfectly right out of the box; it's like they were cast together and then cut apart.  I still plan on installing larger 2.19 valves in the heads, but would there be any benefit to gasket matching the heads and intake to a larger size?  It is going in a light street vehicle with normal street operation.  With the amount of cubes I'm running would gasket matching kill any port velocity I have?  I realize it would move the power band higher in the RPM range but it will be a stop and go/freeway car in the first place.  Sorry for being long winded.

[338Raptor]

Based on what you’re saying I wouldn’t touch them, especially if the head and intake manifold are already matched.  For a 427” street motor you don’t need a huge port, what you have is fairly large already. Going even larger will only hurt your low RPM responsiveness and drivability.
Now if you want a 7,000 RPM beast go for it but that doesn’t seem like the direction you want to go. Even then I would concentrate on the head porting and leave the intake alone.  A mismatched port isn’t going to kill power like most might think as long as the head ports are slightly larger than the intake ports.  That step up in size doesn’t disrupt that much air flow. Now going the other way (large intake port with smaller head port) will absolutely kill air flow and power.
It sounds like you have a good combination, don’t mess it up by trying to gain more air flow when you won’t be able to utilize it.
That’s my opinion.

[TomP]

It will hurt more than help. Disrupts flow.

Ten thousand people are leaving the stadium down a hallway.
 Now the hallway dumps into a room with another same size hallway leading out the other side.
 Does this room speed up the people's exit or slow it down?

[blykins]

That intake manifold will support over 700 hp out of the box on a much larger engine than what you have. 

If you want to improve any hp characteristics, I would work on increasing the flow of the cylinder heads without increasing the port volume.  Also, the correct camshaft will be paramount and early cam timing will be your friend. 

[emorrison96]

Thanks for the excellent responses guys that was exactly what I was looking for.  I won’t get close to the 700hp mark so I’ll leave the ports where they are.  I’m not opposed to increasing to a 4.25” stroke for 482ci but even I’m looking at closer to the 600hp mark.  Thanks again!