I have seen this engine run at a Jacktown show and the build quality is awesome !!!!
https://www.youtube....h?v=qRX3VWWGr30 (Test Run)
https://www.youtube....h?v=KtPI8b3Pf4U (Part 24) ...Wordy, but it's running half-way through the video.
The complete build can be found on You Tube under many parts.
" Homemade 4 Cylinder Briggs Project "
Before building this 4 cylinder engine, they built a 2 cylinder engine which is equally impressive.
I hope you enjoy seeing this!