Just build what you got and have fun. You can build power from a 305 i am getting 400 dynoed hp to the rear tires and 440 tq on my 305 that sports a nice hydralic roller cam, ebay 80.00 trw forged pistons moly rings and eagle lightweight i beam rods. Crank is stoke but i spent hrs on it profiling and polishing it to the same profile as a eagle dragon slayer crank.
The best part is that i was doing the local 1/8th mile here in snohomish and it was pulling 7.51 and looking for more.
Oh did i mention she spins easily to 6400 with the vortec heads and open plenum aluminum high rise with a nice reground hydralic roller cam. It is running 6 psi of boost t4 turbo love. Best of all was when i took my first place trophy position and when i had 20 or so people looking to see what was under the hood since i race for the last 4hrs and never popped the hood. When i popped the hood the eyes ewwhed and ahhhed and ask what engine it was 383 or a 406? I BOASTED that no its a 305 with vortrc heads and they couldnt beleive it. She now has the boost cranked up to 11 psi and i drive it daily. I built the engine for 20psi of love and will turn it up more after i instal the seconf electric fuel pump to keep the fuel to it. Got video of the races of me whooping up on modded wrx`s ,Mustang cobras,2006 vette with slicks, even v8 s-10 and chevy luvs. Oh that 454 open headers thought he would take it when he got me out of the whole.But she pulls hard and i drove right on by him full truck length