My son has an engine not too dissimilar to yours.

He could see that even with the Holley 4150 style 1,000 CFM throttle body with port injection he was still pulling some vacuum.

He went to a tunnel ram and another throttle body and picked up a tenth if I remember correctly.

It it has been on Drag Week many times so it is a true street strip car.

Currently configuring a Kinsler stack injection (converting to EFI) for it but that will be a while before it sees the track.