My ideal goal was to do the same thing with the same car and I did. Only, I didn`t have a 700r4, I had a TH350C and 3.23 posi.
I started with a 880 casting Vortec block. I had it decked .010.
The bore was good so we left it standard.
I used jet hot coated hooker super comp headers.
Dual exhaust, turbo mufflers, crossover pipe.
A comp hydraulic roller cam with .204 duration and .500 lift.
Crane OEM replacement roller lifters, comp heat treated push rods.
906 Vortec heads, springs, locks, retainers to match the cam.
KB Hyper 14cc D dish pistons checked at .015 below deck.
.028 thickness GM head gaskets, Quench distance set at .043
Stock Vortec windage tray.
Edelbrock performer Vortec intake.
K&N Air Filter, cold air induction.
SMI Rochester Quadrajet built to engine specs. Moroso 825 ohm spiral core plug wires, pertronix flame thrower cap and coil.
Cloyes Vortec street single roller timing chain (must be used on a Vortec block)
My idea was, maximize combustion efficientcy hence the use of Vortec heads. Use a Quadrajet for outstanding low end response, a small RV roller cam for less resistance.
A great tune up for a great spark. Tune it all in and see what kind of mileage I could knock off. The machinist screwed up the bore when he honed it, and me, being completely stupid didn`t check the bore clearence. Needless to say, it had piston knock like no tomorrow and didn`t seal up for very long, but for the short time it did, I went from here to Atlanta, all interstate, 70 mph, it knocked off 18 MPG, impressive for a car with a TH350 with a non working lock up tranny and a 3.23 rear. It had outstanding low end torque and throttle response as sensitive as fuel injection. As for your combo, I think the losing factor will be the large chamber heads. They aren`t very efficient.