The B&T will last just about forever as long as its sealed and has grease in it.I had to replace the boot on my 57 when I got it.The replacement was a leather one that was split and laced around the B&T.It was in 10 years when I sold the car.Its still on and has no problems.As stated the input on early trannys is different.The 65 does use a slip joint.CRT and build a bullet proff trans for you.There was a company that was making a shaft that eliminated the B&T used a reg joint and slip yoke that bolted to the trans.Rocky