Being one of OHC six guys that can be counted as such, I agree, make the car what you want and keep the original parts.
I have my numbers matching 2 bbl 350 engine and ST300 in the shed - because I'm putting a Sprint 250 and 200-4R into the car so I can have fun! The OHC engine will be a little "warmer" than stock - turbos, intercooler and EFI - and I'll still be able to afford the gas to drive it as often as I want - daily if the weather's nice (convertible as well). As far as resale, I'll bet that my car would fetch a much better price with the 400 hp turbo EFI OHC 6 with 4-speed auto than the stock base V-8 and 2-speed auto! But maybe that's just me! And I'm not building it to sell either.
I also want to get the better handling that will result from using the lighter engine - hey, maybe you already have the best engine package for the times! Which transmission do you have?