My Question; Would have been what year is the 750 carb.
Do you have a blown power valve, has anyone rejetted it.
Are the floats set right. Is it set or adjusted right.
In cold weather it should run a little richer.
I know alot of people don't like holley's but I have
had good luck with them.
I think Denny is right about the 700 carb, the 600 will
leave the 350 starving for more fuel.
Running to lean is not good either if it starts running
hot you'll know why! Kurt