How about if I give you the spec I got with my TTI exhaust? They tell the measurements of where the crankshaft centerline is supposed to be in relation to the distance from the K-member and the left and right frame rail? Hang on and let me have some coffee before I go out in the garage and find the paperwork. I'll snap you some pics too. be right back...

1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)