Try http://www.hobbybarn.com/engines.htm I wrote him an email making sure Irvine .53's were in stock. Got a reply in about an hour, and ordered one. Shipping is $7.50 http://www2.mailordercentral.com/quantummodels has them also, but their prices are higher than HobbyBarn. I don't know about the .46, but the .53 is a .40 size and is supposed to blow away most .58 engines. - Joe