I've seen a lot of setups on here with Webers, and I read that 4 - 4.5 PSI is the correct pressure to run.

But people on another forum are telling me not to run more than 4 lbs. and that 3.5 is the optimum pressure.

This is confusing me.

Can someone confirm the correct pressure for me?

They were also saying that if I buy a Holley Blue fuel pump that I would have to buy a low pressure regulator instead of the 4-9psi regulator that comes with it.

My carb specifically is a 40 IDF.

Thanks.

 

Straight from Racing Beat-4.5psi