Originally Posted by
David Mason
Thanks Chenny, now I know why the short course stuff is hard to beat, and why I nearly beat the longer one.
Tim, yes the records will stand as they passed inspection at the race site. it was not until a few years later that a 56 CI sleeved down engine was not allowed to run at Hinton. Well, actually I think Mike decided to not run it becasue of some potential issues brought to attention. Cheney says Mike ran a legal 49.9 and I believe him. I ran against that same engine/boat in 1991, 1992, and 1993. No inspector would ever accept an illegal engine, so quit spreading false rumors about Mike and his engine.
My theory is the reason the 56 runs so well sleeved down is becasue of the obvious improved front cover. Straight in shot to the cylinder. No angles. And if memory serves (been a while since I looked at a 56 block) the area was larger, so the reed openings were larger ? Given this theory, that means your front covers and other mods done to improve the flow will work like a charm. From the pics, it looks like you have a straight shot into the cylinder, much like the 56 CI, on the 49 Ci blocks. You need to look at a 56 again, Dave. The front half is identical to the 49.9 - angled and interchangeable. Like Cheney points out, mine have the straight in front halves like my custom built 49.9. Nobody has ever claimed the 56 sleeved down does any better, but I'm sure going to find out.
I can say that a 56CI stock powerhead is an improvment on a 850CCMH boat, over the 49 CI. Maybe it was just a good boat and prop, but it definatly was fast. Fast enough I decided to not try and get this powerhead approved at a National Meeting. This was when the 49CI went out of production in favor of the 56 CI. Right when the laws changed for HP ratings. Maybe a few years after once they began showing up in the junk yards. I will look next time I am at the shop, I still have a 56 block in the junk blocks pile. I decided that if this was approved and people messed with it much it would easily see over 100MPH without a lot of work. I felt people were already on the edge, as at that time, they were running a lot of three holers on D size boats. I did not want to see another person killed racing the class. I already knew of a few killed racing the class.