If what I read is correct, that engine is way overpowered for that airframe. 4.5 HP and 66 oz, should tear that 60 size airframe apart quite quickly. Are you actually referring to a .45? A 45 would be too small, 70 - 90 four stroke would be great, 60 - 75 two stroke would probably work alright.

Information below from the RCU product guide - http://www.rcuniverse.com/product_gu...ineCompare.cfm
Super Tigre
G-4500 Ring

Type: 2-Stroke
Displacement: 2.760 cu. in.
Cylinders: 1

General Specs:
- Bore: 1.750 (in.)
- Stroke: 1.420 (in.)
- Shaft: 10mm x 1.25 thread
- Low RPM: 1500
- High RPM: 8000
- HP: 4.500 bhp@8000 RPM
- Weight: 66.56 oz.

Applications:
- Giant
- Recreation
- Scale
- Sport