I don't know where the project is in status, but I figure I could give some more advice. That engine has what are called E6 heads, they have the same valve size as the E7TE heads that were factory on The 88 and newer 5.0HO. The combustion chamber is heart shaped, unlike the D shape of the e7te heads. Although one might think that because the valve size is the same, that they would perform similar, sadly the valve shrouding of the e6 heads does not promote good flow.
That engine is equipped with flat top pistons, likely of a cast variety. The cam is diffrent from the 5.0 ho model, and obvious the intake is diffrent. On a good day that engine would push 200 hp at the crank, more like 180. The best cheap upgrade you could do is pick up a set of e7te heads and port them out, use a crane cam thats designed to work with the gears and coverter your planning on using, install a 600 cfm (a 500 or 550 would be better) carb. That 750 carb you have is way overkill, that engine in its current state (with e6 heads) would probably not need anymore then 500 cfm of air. Although that 750 may work, poor throttle response, poor gas mpg, and poor driveability should be expected. Using a smaller carb like a 600 cfm holley vac secondary, would give much better driveability and throttle response.
As far as power is concerned, a 302 with a 600cfm carb, edelbrock performer intake (or comparable intake) decent cam, and stock e6 heads should net about 220 hp. Using ported e7 heads, 1.7RRs, and decent headers should net about 260. One thing you have to be carefull of is piston to valve clearence, thoes flat top pistons aren't friendly to high lift, high duration cams..