Hi Guys, I wasn't sure where to put this thread but i did want some people to see it so here it is. We have a mallory 4307 M bypass regulator on our big block. We cannot seem to get it to bypass any fuel. When we turn on the key, the fuel pressure goes pas 15 lbs and won't adjust down to 4 or 5, in fact, it wont adjust at all. Anyone else have this problem? Hope to hear from someone soon. I don't want to send it back to mallory if i don't have to. Thanks

 

Is the vacuum port hooked to anything? I have the same one. Haven't used it yet though. If its boost referenced like mine it needs to have vacuum on it to drop pressure.

 

77, We sent the main body of the dom to pro systems to have them machine a vacuum port into it, just like they're 4500 series setup that comes with a ported regulator. If you haven't seen this, check their site, its by the sv 1. This setup allows vacuum at low idle and as the primaries open up, it cuts off the vacuum to bump up the fuel pressurel. Today we found the mallory wasn't put together correctly, you might check yours before putting it to use. Now we have the bypass working, but the fuel pressure drops instead of staying stable as it should. We're going to try an aeromotive piece i had in the bin box. I'll keep you up on what happens. Thanks for the reply. Bob

 

Mr. Nomad, would You be willing to disassemble your 4307 carefully and tell me the order which the parts are stacked inside the regulator? We took ours apart yesterday and found the return port not screwed into the lower outside body of the reg. That fixed our inability to get any adjustment out of the part. After reassembling the thing we then were able to adjust it, but now when we wing the motor, the fuel pressure drops almost to nothing. I called mallory and they do not have an exploded view anywhere for this regulator. If You don't want to, i understand, I think I may have assembled it incorrectly, but its doubtful since there aren't that many parts in it. If I can't figure this out, I'm just going to buy an areomotive regulator and be done with it. THanks in advance, either way. Bob

 

I'll grab it on the way to work. No problem.

 

77, Thanks for your help, you ever get around chicago, I owe ya a beer. Bob

 

Sorry about the delay, here we go. Looking from the cap working my way inward. Ok, I'm sitting in my recliner at 1am. Everyone is sleeping and I can't get the top of without prying on it. To be continued...

 

Spring, diaphram, big azz needle. It looks like a Vac. secondary on a holley. Thats it. Hope it helps. Sorry for the delay I work 60hrs a week.

 

Thanks for doing this, it helped and didn't at the same time. The mallory was a POS, tossed it. Also had an aeromotive piece that started leaking, tossed that too. Called Pro Systems and ordered their big port regulator, they sell the carb with this regulator, so figured since we had the carb done there, that should work. Thanks again. Bob

 

I got mine as a unused, used piece. I hope I don't have an issue. I may just take you up on the beer though. Me and a couple buddies are thinking about a trip to Joliet. Don't have an event picked out yet, we just need to get away and have some fun.