i've had a 38 on the 40 for about 2yrs now and everything was ok with it. i had been reading about how it should have regulated fuel pressure(3-4 psi),so i thought i would put a regulater on it( a mr gasket i got from jegs). around town everything was cool, in fact after putting it on my warm idle dropped a few rpm's(no tach so don't know how many,maybe 50-100),so i thought everything was good, however i took it out on the road(55mph +) i tryed to pass and it acted like it was running out of gas (not leaning out). pressure was set at an indicated 4 psi. i backed out of the gas and it picked up again.before the return trip i bumped the pressure to 5 psi,once agian everything was good till i put my foot in it. it seems that the regulater isn't flowing enough cfm's. so what make or brand of regulaters do most people put in front of a weber 38 and how does it work for you?