Is a 71t with a 9t on jackshaft a good ratio to climb

[FCMSTREET]

if not i would like to hear from all of you please ...I have a baja motor sports sand dog ..Im changing the 6.5 to a 13 and switching to 40 series 71/2 diameter on driven...along with new belts...that alone is costing 500.00..........i was running the nos barstool racers set up...it worked pretty well ...then just when its going good poooof blew a motor after 6 engines later I m giving up on the nos...going for the 13 hp...i sure hope there's a significant difference for 500.00....please give some knowledge out gentleman...................nobody knows the answer i guess