You want a power vave that opens at about 3 inches of vacuum less than what your engine idles at ( in gear if it's an automatic ). In your case, you will want to go up in size ( numerically speaking ). Most 750's came with ether a 6.5 or an 8.5 PV. If I was you, I would try it like it is first. Cruise down the road at a steady speed and then dip in to the throttle a bit. If you don't experience a hesitation or flat spot. Your PV is probably ok as is. You would be more likely to experience a problem if you went from a low altitude to high.