For all pre A plus 1275 engines with a stepped bush fitting to suit crankshaft.
End float clearances ie .0035 to .0065 - see shim washers DAM6486 to DAM6490. 24 teeth
See C-22G1053 equivalent primary gear with floating bush for performance and longevity where you can change the front bush without having to get it reamed.
Running clearance for this gear-front bush running clearance finished size 1.503" +0.002"-0-0" and for race 1 thou more clearance with plus 1 thou tolerance but never undersize.
Front bush 1.628" +0.002" -0.0" never undersize as it requires clearance.
For race allow an extra thou 1.504" +0.001" only. If cranks are worn measure crank and allow 3-5 thou running clearance and race use 5-7 thou on front bush and 4-5 thou on rear bush.