I have two Homelite 45 timberman 20/18" saws. The latest all red style and the one just before it with the Black top. I havn't needed a model engine this size yet so they are both saws. So I cannot tell you the rpms for sure.

Back about three years ago when people first started doing these, there wasn't enough difference between a Homelite 45 and Poulan 46 to say which one was better?

I also have a like new 60 cc 22" 3750 Poulan that's still a saw. As well as two 32 Macs and a 38 Mac and a dozen weed whackers

I have several acres of trees. The saws come in handy.

I have four other converted engines in the 30-32 cc size so I not hurting for engines.

Jim