Tc Hampton

i have a 89 formula with 113k I have bad vale seals and a lose timing chain the motor is the TBI 305 well my question is I have a 70's 350 block and crank laying around im wondering if I should just buy a 350 rebuild kit and swap all the 305 stuff on the 350 but im gonna port the heads and I was gonna try to go with mild cam and eldbrock performer intake and stock tbi if the l03 heads are not to smart to go with I have 882 heads that need to be reworked but I assumed the 305 heads would be better since they will raise compresson but lower air flow the mods I have on the 305 now is headers, open element filter and msd coil but if you have any insight that would be awesome and the 305 is a roller and the 350 had flat tappet idk if that will make a diffrece or not ... this car is my main transportation so I cant let it be down to long to do this