I agree, you're not going to see much without going mad on an ABF.
We can supply all parts required and we take on engine work, blocks tested and check, cylinder heads tested and checked, porting and gas flowing with valve seat improvements which make good differences over stock, can do big valve heads too.
Then it's just a case of replacing bearings, shells, oil pump, gaskets, guides and stem seals.
All that would cost approx £1,500 though and probably only see you 160-170bhp mark with a decent filter set up and exhaust.