Originally posted by fc227
Hello;
I have a holley 650 , vac. secoundarys. It took me alot of work to block off the under the carb Power Valve and connect it to a exteral port to run to the intake (THIS IS VERY IMPORTANT ON A DRAW THOUGH SETUPS ).
You also have to install a check valve so no Boost pressure get's to the power valve , it will pop it has sure as there is a god.
Another problem is hood clearance , there is not alot and if you use the stock carb. hat you need a 1" spacer under it because the holley choke horn blocks off a good portion of the hat.
I used the red accelerator pump cam, it gave me the best throttle response. 67 jets in the front & 74 in the rear.
The primary power valve vents have been enlarged in my setup. (give more fuel under load).
8.5 " power valve, worked best for me.
I had to have a apator plate milled down to 5/8 " thick , and I had to notch the hood brace for the carb hat to clear.
hope this helps