I have a 1978 242 with the B21A - 4spd drive train.

I also have a 1986 245 parts car with a B230F - 4 + OD tranny.

The B21A is running strong but I am running at 3500 rpm at highway speeds (70mph)

QUESTIONS :

How difficult would it be to drop the 86 drivetrain into the '78?

Would I see a markd difference in performance (fuel economy)?

Would It be better to simply swap transmissions, and leave the B21A engine there?

Is it possible to use the breakerless ignition for the '86 B230F on the B21A? What is involved?

THanks in advance...

Sounds like what you are looking for is lower cruising RPM and better fuel economy?

IMHO, easiest way to accomplish this would be to install the 4spd+OD transmission into the '78. Plenty of 240 turbos (b21FT) were factory-equipped with the M46, so it should be a relatively easy swap.

I've never personally swapped an M45 for an M46 though, so I'm afraid that I can't tell you exactly what changes need to be made to accomodate the M46. Hopefully someone else will chime in here...

-=Bob=-

Answers:

not very, although it is a couple of days work depending on the standards you set yourself for workmanship. The most difficult part would be the intact extraction of the '86 wiring, sensors and electronics and transplanting them into the '78.

Performance: should be better. Of course it depends on what you call marked difference... Economy: probably not very much, the B21 isn't too bad itself.

It would definately be easier.

I would expect so, but haven't done this swap myself. You'ld need to check the figures on advance/retard for both, transfer the distributor and control box, and check from where it gets its signal and transfer that sensor (if any, and possibly flywheel) as well.

Bram