if i swap to carb and delete all emissions junk what kind of gains will i see in a LO3 and also what kind of carb/manifold setups to u guys reccomend

 

The LO3's restriction is mainly in the exhaust and heads - you'll have to get rid of those heads, get headers and open up the exhaust before anything else will be noticable.

For my 1990 I did ported/polished 416 heads, larger intake valves, LT1 cam, exhaust, but kept the TBI, and I can tell there's power there, but the computer is choking on the mods - I'm waiting for emissions to go away in Jan to stick a carb on it and ditch the ECM. With cash wasted on chip tuning, I've got about $1700 in it, and right now it runs no better than stock. After I put on carb and remove the ECM, I feel it'll be closer to 220 HP.

In comparison, in my 1992 I got a 1969 350 block, 1970's smog heads (but have 10:1 dometop pistons to make up the compression loss), headers, Edelbrock 1406 and Performer RPM intake. The motor cost me $600 with carb and intake (used), another $1500 for headers, T/C lockup switch, AFPR, new dizzy, new poly mounts, and misc items, and ditched the ECM and emissions junk - it's got to have closer to 320 HP.

All in all, I spent almost as much on the 305 as I did on the 350 swap - so I can say with experience, don't bother with the 305, do same the work on a 350 - way more bang for the buck! You basically have to get all the same stuff - might as well spend an extra $500-600 for a 350 block to bolt it to!