Along with the revival of my 5 year old project Doodlebug, I am building it now within the same group of friends who has a multitude of projects going on. Namely, a Briggs 12.5 Flathead on a super heavily customized Murray Mower chassis. The engine at hand is a 2006 year Briggs 28V707-1113-E1 (Thats a 28 cube that's apart of the 19/28/31 series, this one being the middle 465cc engine). I'll be honest, im still too young to have had much experience with old flatties to know about modding them old school for racing. What I do know is how limited parts are on anything that isn't a horizontal 5hp. Ya know, the cams, rods, pistons, flywheels, valves, guides, springs, counterweights etc. that go into a high strung race motor. So, if you may bestow me with old school knowledge, what valve springs/cam/rod etc. from what motors serve as an upgrade for these big singles? The mower its on is expected to hit about 5k rpm, and we'd like to eliminate valve float and such at its source without chewing cam lobes and blowing the mill up. With the limited mods for this platform available as bolt ons, I'm opening up my options to include old hacks like stock parts from other factory motors. Really, I just dont know the specs and weights of the stock springs either. Thanks.
