Ive only seen rider engines.  I think in a/p you can use a 10.5 ohv single now.  Ive seen alot people use the briggs 8hp flathead

Me and my friends are building 3 mini pro I didnt know what to get.  Is there any engine better than others or are they all the same?

I see there having a national race on July 26 well in Union Grove,Wisconsin they have had lawnmower races there for there county fair.  Last year they let me and another guy race with them.   Both of us where s/p mowers.  Last year they had a stock class and mod class I heard they are having another class this year for our s/p mowers so they might have a stock class,mod class and s/p class mowers this year.  I will try to find out more information about the race.  But if they do have a class s/p mowers are welcomed to come race.  Last year racing started at 9 and finish at noon. So if s/p mowers wanted to run there could.  Its lake county is around 30-45 minutes away.  They might have more classes to I will try to find out.

Well the rule with the steering angle being in the same position as factory I can still use the rack and pinion if it was legal in a prepared class. 

Alright I see what your saying

I have tiny rack and pinion the only 8 inches long.  Its moves quick to.  I just want to make sure before I make I put it on that I cant run it

Qrc 6x6 beadlock rims have 2 inch backspace.  Van-k 6x6 rim has 2.5 backspace.  Even though the rims look the same I guess there different.   I just measured my rims.