Reworked S/R Torquers?! You still need the baseplate and those heads will cost just as much as vortecs.
You gotta pay to play. How much you want to play? Why would you even bother with a 305 TPI? You could probably get a whole 350 TPI for a couple of hundred. What are you looking for, torque or hp? TPI is all about torque.
If you must stick with a 305 then....Stock vortecs will handle a cam like a Comp XE 256. Want more cam? Then get the valve guide boss cutters that will allow more lift. Pick a pair of vortecs up at the local yard for $200, get your vortec TPI base, and your cam and lifters for $150 and you will have gained 40 horses and torque down low for $800 (or less if you shop smartly, scoggin dickey has the price for baseplate at $399, now you're at $750). Cheap for the gains you make.