Hey folks, after I get the cooling system to my liking, an overdrive transmission is next. The car is a 1964 skylark 455/th400/3.08 10 bolt with 215/65/15 tires. Very mild engine, idles smoothly at 500rpm, stock converter. Anyway, turning 3000 at 70mph is painful. So, either 700r4/2004r is in order. Or, if not too difficult, a 5 speed(my knees ain't bad yet.) I know the 700r4 I'll need the bop adapter plate, how about converter to flex plate, any issues there? Plus, if a bbc should find its way under there, I'm good. Not gonna happen unless the 455 is not rebuildable, but some versatility sounds nice. Never been around a 2004r, but it seems a popular swap, and a couple places claim it can hold the power. 5sp, I know I'll need a bellhousing, someway to make a clutch work, etc. Now, the wildest the 455 will ever see is edelbrock heads, maybe a cam in the low 220* duration. Nothing annoying to drive. So, how should I go about this? I know crossmember and driveshaft will need to be taken care of. Driveshaft is covered, but where would I find a crossmember? Thanks in advance.