Not a 273 expert but if I recall correctly the intake bolt angle is different on those somehow. The sp2p could likely be made to work enlarging or slotting the bolt holes on the intake though.

Is the car currently running? If so what kind of mileage are you getting now?

Yes I think this could be a good car for highway fuel mileage depending upon the rest of the combo. 25mpg should be within reach with possibly slightly more.

I have an sp2p for the 440 I am building for my RV. I'll be doing some testing with it along with a stock 440 thermoquad intake, stock 413 intake with 450 holley, and possibly a performer 440 with a thermoquad. When you only get 6-8 mpg even just a small increase can make a big difference.