Ray,

I had the same dilemma looking for a large In-Line twin for my 1/4 Scale P-40 project. While attending a small Swap Meet/Expo in DuPage Co Illinios, I found a motor manufacturer call Huskey Challenger. It is a machine shop that modifies Huskvarna Chain Saw engines into Model Aircraft engines. He has a number of sizes and specializes in building racing engines for the large Reno style planes. He has built a number of these for Dennis Crooks who is now running them in his competition scale models.

I ordered and received an 8.8 cu-in In-Line twin, with magnisium crankcase and carb elbows and a custom soft mount. The motor weighs 10 lbs, without ignition systems. I paid around $2500 for this and it has been run on the bench. It turns a 28-20, 4 blade at around 6000 rpm!

I have also seen a 1/4 scale P-51 with one of his 12 cu-in twins and the owner was very happy with the power and the manors of this motor.

I do not have his contact information handy, but he is located in a western suburb of Chicago.

I hope this helps,

Paul