Union Bay 670 to 740 big bore kit.

Hello I have a 98 MXZ670 I just bought a new engine which turned out to be a damn close to fresh rebuilt Union Bay bigbore, with new crank, bearings etc. I removed high compression heads and rotor plate so i could run my oil injection, and not need to run race fuel. I got the motor in the sled today and OMG she F****** screams. Does anyone have any idea about what the Hp rating this would prolly be? THe guy who built the motor said with the heads and race gas plus bigger bore carb was running 175hp. No sure if this is accurate but the engine was spectacular, and people are goign to be pissed but I only paid $500 for it with less than 500 miles on it. Anyone with experience with these union bay kits please inform me if u can. I have all the stuff I did not use if anyone is interested in the union bay high comp heads rotor plate, carb boots, misc anondized blue. Thanks Tim

Just the stock exhaust. THe guy had some custom twin pipes but he had to cut the hood to get them to fit. My sled is damn near mint so I did not want to cut into it. Any idea where I can get some exhaust for it? or maybe even a can? Thanks for your help here pal. Tim

Thanks pal going to do that right now. This will be a sick machine, it already scares me so I guess a little more **** in the pants cannot hurt. Thanks again for the insight