Dropped a new B230FT 94-95 Vintage crate motor in the old girl. With only 300 miles on the new motor it is night and day from the old 283K mile B230FT. Can't relay any real performance thoughts since I have to break it in over the next 1500 or so miles. It is so smooth and the power comes on without you even knowing the boost gauge has just pasted 12 psi and climbing fast to 14.5 psi. I haven't raised the rpms past 4000 yet so the rings can properly seat. Told no full power runs for the first 1500 miles and if you can make it 2500K miles just to make sure. The performance gain I've seen with the limited use of the go pedal is an eye opener. As I said the power comes on so smooth with the new motor. The old one was like a slight lag or bog then all hell would break loose. Kept wrestling with whether or not to replace the motor due to the age and amount of driving I do. Walked in to the dealer and said I want a new motor. Was it worth it? Putting a new motor in a 87 745 with 283K miles most would say no. But with a mint body and a pretty nice interior and a totally up dated suspension and performance mods it was worth it. Can't wait for 2500 miles to roll by so I can start pushing the go pedal down farther longer and faster. If your thinking about rebuilding or replacing your motor I will put in my two cents. If the car is in good shape and you plan on keeping it at least 2 more years or longer then go for it. You will not be disappointed.
FYI I had to wait an extra week because the tech that I wanted to install it was tied up putting in a new Turbo motor in a 88 760. My transplant was the 5th motor the dealer has done this year. They said everyone used almost the same excuse why they wanted a new motor. I like the car and don't want to get rid of it yet.