Seriously though, think of basic rules of thermal flow, as with a radiator heat rises & cool falls so if space permitted I would place the fittings with the inlet (hot oil from the engine) at the top & the outlet (cooled oil / return to engine) at the bottom, seems to make sense.
This can be a tricky one , depending on oil pump and cooler used, hot oil should enter at top of cooler and cooled oil exit at bottom or at the opposite side of hot oil entry depending on cooler fiiting arrangement. Ideally your pump should draw oil from the bottom of cooler and circulate through motor into pump and back to cooler. Also if you mount oil cooler behind radiator mount cooler on the cool side of radiator that being opposite side of hot water entry on crossflow radiator, sounds like common sense but ive seen them on the hot side.
it's going to be on the cold side , it's an engine oil cooler using a sandwhich plate on the fiter housing , so all oil has to pass through the cooler under pump pressure ,
it's also mounted on the cool side of the radiator ,
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were we're goin we dont need roads.
it's not the speed of life that scares me, it's the sudden stop at the end ,
Should be no probs then, plumb the hot oil in at top and return to motor from bottom. One way to reduce air lock is to fit up return line to cooler and motor then fill cooler with oil, depending on motor you can prime engine oil pressure till you have oil flowing in line to top of cooler, top up cooler then fit up line from motor to inlet of cooler. Something else you can fit up is a 3 way valve inboth cooler inlet and cooler return line and connect them so that you can stop flow through cooler and retain oil pressure in the case of a crack or hole in cooler while out on track a cheap set up compared to an expense of blown or seized motor.
