1979 el camino 305 what can i do with the engine?

well honestly your going to hate to hear this... all 305 motors were 2 bolt mains.. this really hinders how much power they can make.. and the reliability of the motor.. if you don't want huge cubes, build a 302 motor.. 4 inch bore from a 327/350 and a 3 inch stroke from a 283ci.. in the short and long run a 350 really out weighs the 305 in quality, performance, and reliability..

but if your adamant about keeping the 305 you will first need to redo the cooling system and get a valley girdle to increase the integrity of the engine then you can start from there

Don't worry about the 2 bolt mains - they'll easily support 350 horsepower stock, with stock rods, and no block reinforcement - not that you'll get there without making that 305 very high strung!

I did a 305 for my first build on my 79 Camaro before I stepped it up to a 350 and I ran that build reliably for 120k miles, so here's what I can impart to you:

You'll get a good dose of power from a cam change - the cams were soft in the 305's of that era, so its likely you've worn several lobes practically round. Spec out a mild-performance cam, keeping in mind that what's mellow in a 350 engine will behave as a more radical grind in the smaller-bore 305. I ran a Blue Racer cam, but modern technology makes that cam look like garbage - so I suggest calling some cam manufacturer's tech lines.

If you're doing the 600 carb, be sure to do an Edelbrock Performer intake as well. The stock intake is good for velocity at low rpms, but quickly chokes horsepower potential in the upper revs. I switched from the edelbrock carb back to a performance quadrajet, since the smaller primary bores in the quadrajet offer a stronger signal and better off idle performance. My engine would run a little flat to 2000rpms with the Edelbrock, and I could never dial in a perfect mixture. Maybe you'll be luckier, though.

While you're cleaning the heads, consider a gentle bowl work and some port matching. A couple hours with the grinder, some standard abrasives wheels and stones, and you can cut a lot of performance-robbing flash out of your stock heads, and improve the airflow something like 20%. I'm not saying do a full port and polish - just a cleanup, and knock off the casting flash. Its cheap horsepower you would leave on the table otherwise.

With the cleaned stock heads with 1.6 rockers, headers, edelbrock intake, 600-650 cfm carb, HEI (I'd suggest an aftermarket coil/cap kit) and a good tune up, you should be able to make 260-275 hp with a nice torque curve off of the otherwise stock block - which is good, considering the stock hp of your 305 was likely somewhere around 160 hp!

I suggest that's the power numbers you should aim at, looking to preserve your performance at low rpms's for that moderately heavy elky. Good luck!!!