Yesterday we made three pulls on a chassis dyno to determine optimum max advance. The only change from last years dyno was a switch from a 3.25 axel ratio to 4.33 and a complete ignition change to a dura spark cap conversion with 9mm Ford Racing wires on a stock 57 distributor with Pertronix and a MSD 6AL box. Last years numbers were 231 rwhp with the curve droping off around 6000 rpm and a max rpm of 6500 at 36 degrees total advance. This time we tried 38,40 and 42 degrees and the tiny Y liked 40 best. The most significant change was the increase in rpm. With 6500 rpm being max with the Mallory dual point system, yesterday I bumped the 7000 rev limiter. Perhaps we were experiencing point scatter and a little ion problem with the smaller cap. The hp curve only tailed slightly after 6500 rpm (guess it's that wild cam with 306 advertised total duration, 250 @ .050 and .505 lift). With 237 hp at the rear wheels, the adjusted flywheel hp should be around 280 to 290 hp. That is just over 1.1 hp per cu in (not bad for the 258 cu in "I think I can" tiny Y). With an h-pipe and race mufflers we hope to get to 300 hp by fall.
We have no real race engine experience here, I just keep listning to other Y-Block pros and trying to make positive changes that are within our budget. Nothing about this engine was an original idea of mine. Mentors include (but not limited to) Jerry Christenson, John Mummert and local Y-Block engine builder Tim McMaster. I would just be watching these race events at home on TV if it wasn't for these guys.
Bonneville and Columbus or bust...............
Charlie Burns Laton, Ca (South of Fresno)
BurnsRacing981@gmail.com