I think that BD Maule was wildly optimistic back in the day when preparing spec's for consumer distribution. Esp for that M4-145.
Don't see too many of those around, I do see a fair number of M4-210's &-220's though. They'll give you better performance, as would a 180-horse 170, but that gain in performance ain't free: it comes with a higher purchase price & higher operating costs.
It seems like there are quite a few Stinson's available with 180,210, 220, and 230 horse conversions. If you want a true 4-place airplane, those seem like the best bargains. I'm partial to 180's, but even in this economy they're not cheap. Early 182's can be had for a pretty reasonable price also if you don't mind the nosewheel.
I think one of the best buys out there in a light (2+2) 4-place airplane is the Pacer, esp a PA-22/20- 150 with the Lycoming O-320. They can be had in good shape in the low-to-mid 20's, and with the closest thing to a bullet proof engine there is to boot.
I also want to remind everybody that I've got a good ragwing 170 for sale for $25K- check the marketplace if you're interested.
Eric


