I have a LG4 305 with a holley street avenger 570 and was wondering what kind of distributors can i run? I was thinking about a HEI but don't know how it will hook up. Do I have to run the dual connection distributor with external coil and if so can those support 400-450 horse power? I have a msd 6a box and msd coil now. I'm thinking of changing motors soon. One more question, do i put a fuel pressure regulator on the line from the pump to the carb? just want to make sure.

 

You can use a '70s vintage HEI distributor with integral coil and a vacuum advance. If you want to retain the CD box and external coil, you'll probably have to use a different distributor. The fuel pressure for an LG4 would be appropriate for a Holley with no regulation.

FWIW, you should be O.K. with the Holley. You won't lose too much top end or trap speed. It's only an LG4 anyway.
And your fuel mileage should only drop a little once you get it jetted and adjusted just right.

 

i have nitrous and i'm not getting enough fuel so i am going to get a 130gph fuel pump and regulator, thats why i was wondering about the regulator.