I want to put in a bigger air filter if it would help, but I have tried one and it does not work with how tall the middle shaft is. Is there a kit for it. 1985 mazda rx7 12A

 

www.racingbeat.com has a top hat they sell for their holley kits and the stock nikki carbs. You could look into that. Only kit your probably going to find. I think www.rx7.com has something too for the stock hat, just replaces the top. Wont notice a difference really...

 

The RB kit sounds different, but doesn't add more than 2 HPs. I would still do it though as I have not regretted it.
Here's mine with my Sterling Nikki.

 

You will notice more power from upgrading your ignition than changing your intake filter system. The RB intake kit goes from sucking in air from near the headlight to sucking in air right out of the HOT engine bay. Put the money where it's needed. Exhaust, ignition, brakes, suspension. Don't worry about the intake until you upgrade the carb.

 

Ok, thank you guys and thank you for the insight. I think I am going to hold off on the intake and go with better spark plug wires.

 

back in the Pro7 days we tried a bunch of different setups and the best one is just to feed the stock air cleaner cool air.

the air cleaners were tried with lots of holes cut in them, but it is actually down on power because the air is hotter.

the other (useless) data point is that i have a stock air cleaner on a PP 12A, and its fine up to about 5500-6000rpm, or 170-180 hp, which is plenty

the next step would be to take a spare and add the snorkel, so you could have TWO fresh air ducts

 

what i did once is take that center shaft in the carb and cut that top section off flush with the nut and drill and tap the center for a 1/4-20 piece of threaded rod.

 

Nice...!!