I'm wondering if a few 2M/4M people can weigh in on this for me:
One of my favourite daily drivers was a 2M powered 69 Crown automatic. That car was surprisingly fast. A few years down the road I ended up with a 74 Corona Mk II that had a 4M, also auto, and it was quite a slug really. Not underpowered, but way below what the 2M was. I timed it, replaced everything about the ignition, rebuilt the carb, and nothing seemed to be able to coax more power out of it.
I had a conversation with a long-time Toyota dealership owner about it once, and he said he remembered a lot of the 4Ms coming back within a couple years after they were bought with similar complaints. He mentioned that he remembered the problem being that the camshaft wore more quickly than expected, and that this wasn't a problem which the 2Ms had. That Corona Mk II caried on without me and I never got it running as I thought it should.
So, fast forward ten years, and I'm again considering a 4M Mk II project, or a 2M Crown (or an 18RC Corona.) I know the easy swap for the Mk II would be to plumb in a 7M, but I like going for the stock look. What's been people's experience with getting decent power out of an older 4M? Are they almost always a bit anemic?