The Performer intake is ideal for a "performance" 305. Not too big... The Wieand is among the better doorstops on the market... It's a genuine imitation imitation Torker (Holley Street Dominator is the "original" imitation Torker).
The 670 carb may be a tad on the "big" side for the little small block. An Edelbrock 550 might be a better choice. As a "Street Avenger", does that mean it has vacuum secondary? If so, it will be okay. If you could find one of those old "little" Q-Jets from the '67 326 HO, now THAT would be the ticket.
350 heads on a 305 will do exactly what TOHcan says, reduce compression to a woeful point. Also note that no 305 (including the "HO) came with intake valves larger than 1.84". The smaller bore is the reason. Just like the Pontiac, valve "shrouding" is a real issue here.
A cam would really be called for to make all the external mods "work". I like the Comp XE grinds, but a conservative approach (cams, not politics) is better for such an engine. The XE250H or 255DEH ("Dual Energy") would be my choice.
Once you've gotten this thing going the way you want it, and start saving for the new engine, I'll donate a 400 block to make it a Pontiac! It takes a WHOLE LOT of 383 Chevy to equal 400 Pontiac... (:-
