Heres and old and ongoing problem in my '70 145s with a weber DGV, on a B20B.
Car idles and runs fine up to highway speeds (50 mph ish)
However after I get it on the freeway (75mph ish) it will start bucking and stalling. Sometimes I can feather the throttle and it comes back enough to get me to the next offramp, and the car does fine at 30mph.
Other times it ends up on the shoulder.
After about 15 minutes or so, it starts and runs fine again.
That 15 minutes has historicaly been enough time for me to find and "fix" something wrong. One time it was the in-pump fuel filter that was clogged with tank gunk, another time it was swapping out the pertronix with a spare set of points I keep in the glove box.
Obviosly, those wherent the real fix. The filters where clean the next time it stalled and the pertronix is happily sparking away in the Penta aq110 in my boat.
Ive also swapped the dizzy with no change to try and rule out stiky wieghts.

Then, the other day, I had reason to go wide open throttle from 25mph to 40mph (passing in a 35 mph zone) and the same problem occured.
Thats when the light went off in my head that it might not be a speed/rpm thing, but a "second barrel" thing. Im not sure what exactly that would be but now I'm thinking this particular gremlin lives in the old Webber of dubios origions I have in this car
Are there any known issues to back my new theory up? Like a sticky butterfly, or a sticky float?
Also, Im wondering what else to look at if this problem persists after putting the SU's on.......

Thanks,
Dave.