I assume your using the "floater" dual idler set up, just make sure the large idler gear is on the left side, LOOKING at the engine, you'll need to file/trim down the cam thrust button that contacts the front cover, measure carefully, take into account gasket thickness of the timing cover, clearance for the thrust button from the timing cover is .005-.075...when you have installed the top and bottom cam/crank gear, line the dots up, just as you would a standard timing chain, install the dual idler, you may need to grind down the back of the idlers axle buttons in the back as they may contact the back of the block, the thrust buttons on each idler axle gear is designed to contact the timing cover, so install the idler gears halfway meshing the cam/crank gears, push them into place with the timing cover and gasket, do not line up the gears face to face, the idlers must be stepped forward, let the timing cover and gasket push the gears into their "idle/thrust" position against the cover, temporarly put the cover on and rotate the motor over, remove the cover and see if the idler gear rear axles are contacting any portion of the block, if so grind away the axle hub further, there's usually plenty of meat to grind, perform the cover/rotation test untill the idler gear rear axles no longer contact the block, minimun of .005 clearance is needed, no more than .025 between the idlers rear axles and block interference, failure to make sure the rear idler axles don't contact the block will result in the block being ground down, not to mention gear failure, just make sure you ALWAYS rotate the engine in the correct running rotation to insure the idlers are meshed in the proper driving position, measure everything, assume nothing, double check everything,...you'll need to install a desired offset button on the cam's dowel, they range from 0 degree to 2,4,6,8 degrees, color usually denotes the degree, gray 0,gold 2, copper4, silver 6, black 8,...when veiwing the cam offset button the center hole and it's offset should be facing to the right side for the cam "advance" position, to retartd the cam, flip the bushing over so the center hole faces to left during install, when you install the offset bushing in the desired position, you'll see that you need to rotate the busing for proper gear engagement, make sure you can lift with your fingers the small idler gear up and down .005-.060 when the large idler gear is fully engaged with the cam/crank gear, the small idler must have proper clearance, otherwise to much running friction will destroy the idler gears, you can still use a degree wheel to set your cam up properly, if your unsure of degreeing your cam, which I recommend, then use the 0 degree bushing, that will be the cam dowel bushing (usually gray) with the perfectly centered hole, do make sure the timing dots on the cam/crank gear are lined up to each other,...also make sure the metal tangs are folded over the 3 cam bolts, the flat metal plate installed under the 3 cam bolts, this keeps the bolts from backing off,...I think I covered everthing, PM me for any Q's you might have
PS.....you'll need to toss the factory oil slinger, not needed, just make sure to install a new crank seal in the cover, and lube with moly grease before fire up
Mike