Hello. I have an EA81 engine. Is there any tips/tricks to get better air intake?

start with a better exhaust. you can only draw in as much air as you can move out the tail

 

i use a stock y pip with a 2 1/4 inch cherry bomb immediately after, and 3 inch pipe after that.

the ypipe will get my scavenging, the bomb will get my backpressure and exhaust pulse, and the 3 inch pip elets it all flow out.

 

remove the ductwork that connects the airbox to the inner fender. take the box off completely and put one of those autozone holley triangle filter assemblies

 

wait till you blow a head gasket and poke the heads out with a dremel as you fix the head gasket

How would a flowmaster work with this? And what about the Cat? I've heard just put a cherry bomb on it?