I think everyone gets what you are saying. But from what you are saying this isn't even worth the effort. We my as well just leave it be. I find it hard to believe that it womt be noticeable at all. Smaller chamber heads with bigger valve should bump up the compression some. Depending on the piston clearance we could run a thinner head gasket to help with quench and compression. Is it a perfect plan not at all Will it be an improvement? You betcha. And it will work nice with the stroker kit down the road. I had people telling me the same thing with my 352. And you know what they were right. I should have held out and got a 390 for my car. But it definitely made a difference. My car went from making a bunch of noise to running ok now. Is it all that I wanted? No not even close but it will hold me over until I can stroke it out to a 445.
The run down on his truck is a it's a stock rebuilt 318 with a 2bbl carb and intake. 4.10 gears front and back with 31" tires. It has the 727 with a fulltime np203 transfercase in it. Timing is set at *14 initial with *22 mechanical for *36 all in by 3400 rpm. The plan is to ditch the np203 for a part time np205. At that time we will probably change the converter also. Maybe a turbo would be the better option here with the low compression.
