[DeTomaso] vacuum vavle source, fuel vapor venting question

[Paul A. Rimov]

Afternoon all:

Need/want to vent fuel tank vapors on my EFI system back into the engine.

Looking for a source for a vacuum controlled valve that I can use for venting fuel tank vapors back into the engine. I am looking for an in line value/regulator that closes or restricts vacuum when engine vacuum is applied and opens when then engine stops that I can run off one of the manifold vacuum ports. I tried running a manifold vacuum line strait to the gas tank and it started sucking the tank walls in, toooo much vacuum. 

Other options include running the vent line to a filter or pluming a fitting just before the throttle body and hooking the fuel vent line to vent any fuel vapors

Thanks


Paul