[Formulajones]

Originally Posted by HWYSTR455

I've found that vented caps do not offer enough venting for most requirements, and any mods to the cap make them spit out on WOT.

I guess it would depend on how much fuel you're feeding the engine?

I don't know, dad's GTO is the stock 69 vent system, which isn't much, but we found that to work fine with a 571 and 724 hp using a 400 lph walbro pump in the tank. He's went from carb fuel pressures to now 60 PSI with a Holley stealth EFI unit, and it's been great.

I'm just using the stock charcoal canister as a vent on my 72 chevelle with a 600hp 454, and the same 400 lph walbro pump in the tank. It's working fine.

A real NOS vented cap will in fact leak a little fuel on WOT launch if the tank is full. That's a normal deal. The repop stuff doesn't and I think that was part of the fuel feeding problem with those things, they didn't work quite like an original vented cap, and today I don't think they are allowed to make them that way anymore. That's why I bought an NOS piece for our Camaro.