I'm not 100% sure but at least 98% sure that Pete had a novak in his car in 10.5. Spec is a different animal than boosted though so without actually running it I couldn't tell ya which would be best but the top 3 motor companies are all going to be very close with the right combo.
we ran 10.5 spec on a 365 paved oval. the thunderpower motor was quicker over the run than the novak but the novak would full quicker times up front. This was with the older red wire stator, cant speak for the new stuff.
For spec I would suggest the Thunder Power. With the optional tuning rotors they would be my choice for spec over the Novak. We haven't had enough time to fully test the new D3.5 10.5 in spec, but the D3.5 17.5's have been impressive so far.
Feel free to contact me M-F 9-5 EST if you have any questions-:thumbsup: