I've race Mopars since 1964, I build my own motors and have torn down a bunch of early,1967 up to 1971, 440 magnum (HP) motors, none of them where any where close to having the piston deck heights and combustion chamber volume where they should be to make the advertised compression ratio, they all had true lower compression
On your deal I would try it to see if you can notice a difference or not
Please let us know what you find, that will help others on here
I have not heard the term "recreational gas" , maybe it is not sold here in central OR
I run my S/P bracket car on E85, the station that sells it also sells all kinds of race gas from their pumps
Non ethanol gas will make more power and go further down the road(better mileage) than the E10 or E15 will with the same amount of fuel