340 Chugging instead of Reving

AJ/FormS said

OK no you missed the point; if your engine begins to run stupid at the crossover point... maybe the box is bad.
I suggest to put a timing lite on it and see what happens to the timing as the rpm goes thru there.

However, seeing the plugs now, wow, they are all over the place.
looks like a couple are oil-fouled, a couple are rich fouled two are a lil lean not much, and two could be called typical; so that's quite a story

Click to expand...

I was reading between the lines that you may be pointing out the similarity of the 3000rpm dead zone. But figured I'd answere your question regarding MSD. But... I do get what your saying and it's certainly another part to investigate. At one point (with a cheezy timing lite) it appeared to bounce around. Maybe it wasn't the lite.

The 72s were in it when I bought. After break in I figured the jets and power valve could be dialed in better.