I recall that the 455 dizzy has one more tooth on the gear than a 350 does, other than that (if correct), is there any differences? If not, would they swap from one another (with gear changes, providing that is the only difference) with little to no issue?
You are correct, they are identical except the gear. The only other difference would be the advance curve built into the distributor.
That difference can be quite substantial. It is the amount of mechanical advance built into the distributor, and that is what determines how much initial advance you can run with a given total advance.
Aside from that, could one change the weights/springs, the gear, and plop a 455 dizzy into a 350, or a 350 dizzy into a 455?
Yes, aside from that you can. I've never experienced different roll pin sizes personally, as far as point dizzy's go.
Can we stop referring to them as "dizzys" please? Yes, you can physically replace the gear and put a 350 distributor into a 455
It is not that simple. Weights and springs are not what determines THE AMOUNT of mechanical advance in each distributor. It is the advance slot. The big cap HEI weights and center piece determine the amount of advance in those distributors. Does anyone read my Power Timing thread?
I read your thread Larry, and like Jason explained, I'm well aware of the different shafts, the advance, etc. He asked if you could do it and YOU CAN. I absolutely agree you are not going to get the best performance possible, but you can do it, you can drive the car, the world's not going to end. I'm pretty sure you can put certain Cadillac + Olds distributors in and they will work if you change the gear. It's not the best thing to do, though. Maybe Mr Sony lives in Cuba and can't get the right distributor? This reminds me of when somebody asked if there was a right way to put on the gear and I said there was, then a wazillion people said there wasn't a "correct way", it doesn't matter... I stand by my answer, absolutely you can do it, but it is good to understand the big picture. Knowing Jason, I'm also positive if his 455 distributor broke in Timbuktu, and he had a 350 distributor in the trunk, that gear would be swapped pretty quickly! We are here to confuse you.
Frank, I not saying you can't do it, I'm just saying that there is a difference in the amount of advance built into each of the distributors, and that it varied, sometimes a lot. With all the confusion out there about ignition timing, I can see someone swapping distributors using whatever initial timing they were using before and then wondering why the engine either had no power, or was doing a cheap imitation of a diesel.
