I am always interested in these conversations. Engine thermal efficiency usually is less than 100%, but not always. The use of computers are a help, because many engine dynamics can be controlled precisely. AR ratios, timing curve, etc. some old car had an overdrive, which was touted to get better mileage, and did. SO, how is engine efficiency made better? Raising the compression ratio helps, in a number of ways. Piston volume, head volume, or by some type of pressure greater than atmospheric, like a turbocharger. The newer rings on pistons are much thinner then the old school rings = less friction. You have many options only if you have an unlimited budget. Budget will dictate what can be done. Lower numeric gears will help, IE going from 4.10 to 3.55, but that can be a two edged sword as well , depending on what rpm your engine is most efficient at, which is, in a basic sense, where the torque and hp cross. It won’t be at 2000 rpms. It is a compromise. Remember higher compression will eventually require higher quality gas, personally, in Wa St. gas prices are very high. So to recap, raise compression no more that 9.5 for reg gas with a short overlap highest lift flat tappet cam you can buy, and yes Rhodes are good lifters. Change the gears to fit your cruse goals, IE 2000 rpm cruse will require 33 inch tires, 2.81 gears, or overdrive. If going for overdrive, 4l80e, my trans of choice. But the most important thing, is, study, read, educate yourself. I have tons of books, many obsolete now, but David Visard on YouTube and his books are a wealth of info. In the end hope it is fun, it’s supposed to be.
