Here is a great little old school OS MAX .40 I think its a ball barring engine but not sure. I never ran this one . It has great compression and the barrings are smooth. The muffler is high performance add on I think by Macs mufflers and is rare to find these flow through style, these are great for a little extra rpm's and maybe the extra bit you need to be a winner. The shipping is free so if your looking for a good deal on a great 40 here it is. Paypal only please and lower 48 only, thank you!