318 build for light weight BCuda 4 speed car

Don't have experience with a 4 spd, nor a Tunnel ram, but I did run a Teener in my 65 Back-a-ruda, my best time with it was 12.54, 108mph; full write up is in 12 second combos; tires were M/T 275/60x15 drag radials, basically a 28x9 tire, gears were 4.88's; engine was single 4 bbl, 904 tranny with 4500 rpm stall converter.......I ran a Comp Cams XTQ281s-6, it screamed.

My opinion is that you could use less tire, ie shorter, or more gear.......30 inch tire is a lot of tire......you'll be fighting bog off the line...the OD 4 spds are not known as rugged units and I can't say that I have ever heard about people racing them; as you pointed out it's all about the gear spacing.....your 65 tranny would be a better choice as the gaps between 2nd, 3rd, and 4th are closer together, the rub there is the trunion flange, I think but I am not 100% certain that you could swap the 65 guts into the aluminum OD case, use the OD main shaft, get rid of the trunion flange and some weight.

Good luck!!