Actually Tom Langdon and I talked about that some years ago. He said there were a couple of reasons aside from the cost savings. One, having the coil right at the distributor simplified production, installation and servicing in one swoop. And also as important to those, it made the distributor measurably more efficient.
My suggestion would be this:
person looking at your engine "duh, is that a stock distributor?"
Your answer "yes, you bet it is." And stop at that point so you don't have to explain it isn't a stock distributor for the 235.
Again, here are a few good points: everything in it is brand new (including the vacuum advance biscuit), GM replacement parts are available essentially everywhere (try to find a Pertronix module in Monahans, Texas). And they last. The one I'm using has been in use off/on since 1997 (over 25 years) and nothing has broken on it and nothing needs to be replaced. I bought a new connector device...actually I think they were 4 for $10 on Amazon, but that was only because I had been using a single + plug and I wanted an output for a tachometer. And...if you're one who likes to tinker, the advance curve can be adjusted by monkeying with the springs.
