1984 el Camino 305 won't start

[Texas82GP]

but more on the cost efficient side

Those are fairly entry level long blocks budget wise. You could go with the standard GM Goodwrench 350.
https://m.summitracing.com/parts/na...-performance&gclid=CKvajv75mc8CFdgTgQodqWsHjA
You won't do much better than that except maybe a rebuilt engine or buy something used. You get what you pay for.

 

[565bbchevy]

The cheapest GM long block 350 crate engine is around $1500 for the 195 horse version but Super Chevy built a blower engine with this long block and the baselined it with a Holley 650, an Edelbrock air gap intake and 1.75 headers and it produced 287 horse and 361 ft lbs of torque not a bad deal for the price plus everything is new not rebuilt.

 

[Rlynch132]

LS Swap!!!