Hey guys, happy new year. I just got my 68 142 a couple months ago and was wondering about upgrading transmissions. It has a 74 b20 with the weber DGV and an M40 tranny. Anyway, the gearing is to high and I would like to upgrade to a m41 or toyota 5spd. Then again, I will be converting to dual SUs pretty soon and was wondering if the puny driveline/shaft can handle this. I will be doing a little drag racing and autocrossing, so I'm looking for something that can handle it... Also, any info about LSDs would be great also. Please let me Know! Thanks!

Converting to an M41 is not too big a deal... you just need the parts. Specifically, the transmission, crossmember, and driveshaft. And a few other things like speedometer cable... The early M41 transmissions will have the smaller driveshaft flange to match your rear end. If you go with a later box, it will require the larger driveshaft, and you'll have to make a change somewhere in the flanges, or the driveshaft... THe later M41 with the large driveshaft would probably have the J-type overdrive, which is preferable (I think) to the earlier D-type OD....

A Toyota box would be much more involved... can't help with any advice there...

Pulling the weber and installing the two SUs isn't going to get much of a power gain. The small driveshaft would handle the power fine.

As for the lsd rear... don't know fi there are easily obtainable parts to convert yours or not. My guess is no. Best to get lucky and find a complete rear off a donor car. If you do find a system that works, by all means let us know.

Have fun, and drive safely!
-Matt

Any 140,164,1800E/ES,240,260,700 (and probably 900) solid axle limited slip will go in your car.I'm going to pull one out of my 82 240 and put it in my 69 soon.

Are the 2xx and 7xx diffs a direct swap or are there some minor differences (eg. track rod position/mount diameter?)

Thanks!
--
Alex Shevlin (Sydney): '71 142S, '72 144S, '81 244GLE, '81 244GL, '01 V70XC

I've never made any sense of the different flange sizes -- I've got a '75 M41 J-type from a 240, and it interchanges with my '67 D-type... same flange size. Certainly other flanges are running around out there, so get the front shaft from the donor car just in case. The driveline shop that shortens your original shaft can easily make the switch at the same time if required.

The J-type gives a .79 reduction, and the D-type a .75 reduction (the D-type drops your revs just a tad more, in other words).

The driveline is plenty strong enough if you use decent U-joints, no worries. You'll break second gear before you break the shaft (if you drive like an idiot instead of driving the fast way).

SUs, properly tuned and in good shape -- repeat: properly tuned and in good shape -- will clearly outperform the Weber DGV, also properly tuned and in good shape. I like the DGV for its low maintenance and fuel economy, and it supports up to 130 HP if you got 'em, but it's essentially a tiny carb.

DGV = one 32mm choke and one 36mm choke. Airflow has to go around a 90-degree bend and down intake runners that are two different lengths.

Dual SU HS6 = two 46mm chokes, variable venturi design, airflow gets a straight shot at the intake ports.

I don't know how there can be any argument about which inherently gives more performance, except by people that replaced worn-out and/or mistuned SUs with a new DGV and found that (no surprise) it runs better.