I recently picked up a 57 lark model 25532 to compliment 57 sportwin and my collection of various other motors of that vintage. when i got it home the first thing i did was try to check compression which was 135 top and bottom and for rod\wrist pin bearing slop by pushing down on the piston with a screw driver but was unable to feel any play. when i started it for the first time i could tell something was not right a pretty loud knock was comming from what appeared to be the powerhead so i assumed it would be a bad gear in the gear case but before i tore into the lower unit i decided to check the piston play again and i was dissapointed to feel about 1\16 slop in in the bottom cylinder. i proceeded to hop on my handy dandy computer and try to locate parts but have came to a halt when i was unable to locate big end bearings. this powerhead has too good of compression to really make me want to swap it out for another unknown unit but im not even sure if its the original power head cus the casting plug with the model number is missing i would think it would have some gray paint if it was a lark power head i know they used the electric motor wiring bake on paint for primer on these but the only gray is on the inspection\intake covers the exhaust housing cover head and reedvalve cover so its very possable that its a swapped on power head by the previous owners the guy i bought it from knows nothing about or so he says. so i thought id register with aomci and ask my question there but was unable to complete registration for some reason. my next move was to come here and ask here cus this is my other choice for finding info for my other various old motors i own if anyone has any input or a source for rod bearings id like to hear their opinions.