We are building a Extra 300 kit from great planes and we are having a hard time deciding on what engine to use and we are thinking of using a O.S.-.55 -.61-.75 as our options and they are all powerful engines but the weight of the plane and where the weight is on the plane (tail heavy, nose heavy) decides what engine to purchase.

What is your option on what engine we should buy?


Thanks,
Flyer 202

You're building the 60 size GP Extra?

Mine used a 91FX & Bisson pitts muffler (same dimensions as the 61FX) and the plane balanced without needing any additional noseweight and flew with plenty of authority.

It is a .40 size Extra 300 and we are planning on using a Pitts muffler.

Thanks
Flyer 202

i did the gp 40 cap kit and used the tt .46 with pitts muffler that was plenty of power and balance was almost right on.i think i might get the extra kit and put a 4 cycle in it a saito .72 i read here they sound good in those kits and have plenty of power.keep us posted im curious on how it turns out