First, Which parts will I need to complete the longblock? Water pump, valve covers, intake, carb? What else. What companies should I check out? I want a mild 289 or 302. What's the level of knowledge needed to complete a longblock?
You will need the oilpan, timing cover, waterpump, intake manifold,carb,exhaust manifolds or headers,valve covers, distributor, and oil pump drive shaft. A long block generally comes with the assembled shortblock, ( the oilpump usually comes with it, but you have to bolt it on yourself) plus the fully assembled heads bolted on and torqued ( supposedly, it's best to recheck torque values on everything) in place. Not hared to complete a longblock ( or short block) but you will need a torque wrench and an assembly manual to do it correctly.