Ah ok so the older frame stuff isn't so wobbly then. They both had 28s on and just yeah flopped around heaps. They were farmers saws and haven't done bigger all work there was a 381 sitting there too but never picked it up.
I'm with Todd it's not about speed for me it still needs to cut well ofcourse but yeah I cut for enjoyment the firewood is a by product lol
The other thing is a hi rpm saw like that 441 it had nothing down low and in dodgy situations where ya just need to baby it through to avoid a nasty kick you know is coming or avoiding a fence or the dirt it just wouldn't it needed to be singing to drag the chain through.
Is the 661 the same?
My step brother has a 311 and yeah your 3700 will probably out cut it dam neer I know my 4000 has a fair bit more pull than the 311 and a nicer power band also. plus nicer to touch/look at/repair the 311 isn't exactly light eather.
Here's a vid of the 4000 with a 311 in the background