318 For Fun

Some ported 234 or 973 casting heads with larger valves would keep the port velocity up and flow pretty decently, but a set of bare speedmaster iron magnum heads would make a better starting point. It is possible to adapt an LA intake manifolds for use with magnum heads (or maybe even drill magnum heads on a mill to accept an LA intake?), but the assault racing air gap intake will make all the torque you could ever need. I've done it on a 318 magnum with the smallest cam upgrade imaginable and it made earth mover levels of torque. Confirmed by over 10,000 pound towing use in a relatively high geared truck. With a magnum head the selected cam becomes a .511/.526 piece by virtue of the 1.6;1 rockers. But what exactly are you planning on putting this into and what gears are you planning on running? I ask because the goal for the RPM limit is in the realm of a 1/4 mile pavement track pure stock car. I don't know of any quickly accelerating street builds that don't get spun past 5,000 at some point and then it becoming pretty commonplace from there.