vwspec

I just purchased a 1985 elcamino with 4.6 auto. I want to do complete overhaul. Need discussion on 5.3,5.7, or 6.0 with 5/6 speed. Going back carburation, need input which engine with small mod, cam, intake, carb, headers, and which gears in rear. Looking to possible tranny from camaro,ect. Have a budget of course, a good HP & torque engine for just cruising. Not concerned with MPG as long as it stays above 13-14? Any input would be greatly appreciated, new to vortec/LS engines, Thanks, vwspec