The 550 IQs I built sporting 163 tracks are awesome. With that said I think the PRO chassis would be a remarkable upgrade.
I would add oil to the gas, they love oil. I pulled the oilers and run 32:1 mixed fuel. One has 34mm carbs the other has 38mm rack carbs. Both have exhaust cans from HPS.
Both run 18-46 gearing, P2 secondary's with a helix I had Dalton cut and 68 gram lightning weights.
I would by the 144 PRO 550 in a heart beat and ditch their new antiquated clutches for a P85 and P2 secondary.
I would add oil to the gas, they love oil. I pulled the oilers and run 32:1 mixed fuel. One has 34mm carbs the other has 38mm rack carbs. Both have exhaust cans from HPS.
Both run 18-46 gearing, P2 secondary's with a helix I had Dalton cut and 68 gram lightning weights.
I would by the 144 PRO 550 in a heart beat and ditch their new antiquated clutches for a P85 and P2 secondary.