Hi JD
I recently had a seized Briggs and Stratton powered little 2 kva genny landed on me, by Ramon, our local shepherd, it had no tank or carb and the linkage from the governor had disappeared as well.
The Briggs had the mounting bolts drilled at an angle of about 25 degrees.
I freed the piston off with ATF and acetone and 'honed' the bore with wet and dry.
To test it I ran it up on Angels Breath' - Start Pilot, or ether. it didn't sound too bad so I invested 9€ in a Chinese pit bike 'racing' carb, complete with a knock off K&N filter. Free post and it arrived in around 10 days, bargain!
I drilled and tapped the head M6 and ignored the 'oblique' holes
With the carb fitted the exhaust wouldn't so I fabricobbled a straight thro' pipe, to complement the racing theme and it ran lovely, and not too loud - well there's not that much noise in a 175cc flat head, is there?
I used the tank of a Loncin snowblower engine and rashered that down to the frame with self tapping tech screws. I did add an inline fuel filter, to try and get some street cred back...
As Ramon wanted it for lighting in a remote sheep barn (stone built, circa 1750) I plugged everything in and wound out a fabricobbled throttle to fix the revs at the point where the motor sounded happy and the lights were just at max output.
It's been up the hill a couple of months now, and he's not bought it back yet - anything I fix for a shepherd up here is deemed to have a lifetime guarantee, my lifetime, mind you the clocks went back last weekend and the nights are getting lighter........
As for your project I'd go with one of these
eBay item number:133164884120
Cheap and cheerful and everything is there. If you have to ovalise the holes one way or the other to make it fit the studs it won't break your heart and with the knock off air filter and dinky fuel filter it's bound to make the grade in the custom section at the (now postponed) local steam fair!
Cheers
Stef