I am putting heads from a 305 TBI onto a 350 TBI. What issues will I run into. I know the diffrences in the heads (valves, chamber cc's). Will there be a computer issue?

Probably won't have any computer issues. But you might get some knock counts if you don't run a higher octane gas.

I helped a guy install a 355 with a built bottom end with a set of 305 torquer heads that were from my 305 experiment for power (ran good but not enough).
It took his mild compression of like 9:2;1 and bumped it to right about 10:1 is the motor stock that your putting the 305 heads on? if it has flatop or pop up piston in it your compression is going to be really high. should give it some good thump :-)

Everything is stock. I was doing a head gasket job for my cousin and I noticed a crack in the rear combustion chamber starting from the seat of the intake valve. To save him some money I offered my original 305 heads. So to answer your question, no flat tops, the pistons are original, with the valve reliefs.

Flat-tops have valve reliefs but no dish. LO5 typically had slightly dished pistons with valve reliefs. Fully dished pistons don't require valve reliefs.

A thick head gasket will help relieve some of the compression.

You'll also be reducing the size of the intake valves from 1.94" to 1.84".

the intakes are 1.81 or so on the intakes of the z28 heads but on all other stock 305 they have like 1.78 valves or at least close to that I remember that the z28 heads had larger valves I thought