by TFR1 » Mon Feb 18, 2013 6:52 pm
Charlie,
You have probably forgotten more about engine building than I will ever know. So forgive me if I seem a little slow about sorting out these details.
The reason for using a Cooper block is apearance only! The goal is to build an engine with less than a 1000cc so that my Bugeye can run in the small engine class. A Cooper block with tappet covers looks very much like a 950 block.
Many years ago(1985) I had Dave Tabor build an "all you can do" 948 engine that was "vintage legal", not SCCA legal, .060 over bore, larger valves, DCOE 40 webber carb. Engine dyno tested at 103hp @ 8300 rpm. Displacement 995cc I think.
The Cooper S based engine I built in 1992 used .040 over sized Omega 6cc dished pistons, 6" carillo rods, special 970 stroke Farndon crankshaft, along with the Richard Longman special bits. Engine dyno tested at 115 hp @ 9500 rpm. (998cc if I remember correctly)
So you are right, the best way to do this would be to start with a stout A+ block, offset bore it, install a 970 stroke crank and twist it as high as we dare.
One problem I did have was finding a proper rear end ratio. 4.55 was almost to tall at most tracks.
Thanks again for the input. I still have much to learn.