New build, How bad off will the tune be? (Kinda long post)

[Musclemustang65]

First off I AM going to get a full dyno tune but I feel the stock 170k mile trans wont hold up on the dyno and don't want to drive over 2 hours just to need it towed home broke and untuned. So I want to wait until the transmission can be built but with the cost of a stall, and me scraping up money just to get the motor finished, it will be a couple months before I can do this.
Im not going to do any racing during this time, nor tons of driving. Im just curious how bad the car may run lean or rich and if it would be enough to hurt it with minor driving.
It is a 95 gt (Which I know will be pissy with an unturned cam) and will have a 306, 9.6:1 compression, AFR 185 heads/1.6 roller rockers, comp 274hr cam, edelbrock RPM intake, 75mm throttle body/Cold air intake, Bullet MAF (78mm I believe) with calibrated 38lb injectors, 255lb fuel pump, Msd dig 6 box,Shorty headers/stock exhaust, etc....

With basically all induction and exhaust parts being upgraded BUT with a calibrated MAF/Injectors im really unsure how bad rich or lean it may be running and I cant afford a new wideband right now to find out.

I posted a thread somewhere about this but have no idea where it is so here it is again.