HI Bob the gear sets you can get from
www.powerhausii.com and
www.carquip.com or
www.guardtransmission.com all have good gear sets, If you must use a 7:31 CWP then fit a gearbox oil pump and spray bar set to lube/cool the gears/CWP. The 81 engine should have nicasill cylinders, so a JE piston set, if the cylinders are OK that is , boat-tail the case, twin-plug the heads and flow the heads, std valves with the angels re cut to flow , DC60 cams from 'camgrinder' and springs to match, TI retainers if you like, std rockers re- faced and bushed, std rocker shafts, not re-furbed, dist from supertech with the advance to match the engine, carb's from PMO 46, manifold to match the heads, Richard at PMO will do a basic jet setup when you order the carbs, which is usually pretty close, exhaust is std back-box 2 in/1 out, std flywheel and clutch, unless the $$will go to something lighter, and then there is the gasket sets, nuts/bolts, bearings and bits you cannot see till the engine is in bits that require re-placing, as for the price, well, if you put the labor in then it is only the price of the parts/head/balancing jobs'which will save you $$ but not time , if you get the job into a tuners , well you will have to ask for a est' for the work, over hear it will be £10-12,000 ($19000)+ the engine, which you have, it will be a lot cheaper in the USA and a lot cheaper if you DIY.
regards mike