I've got the 170 4cylinder in my 77 V thats a 85-86 model motor. Its been bored .040 over and I replaced almost everything but the block, crank and intake. It runs great now ,but has taken awhile to work out some bugs. I changed it over to electronic ignition and that probley helped the performance more than anything.Its been changed over to an external alternator and I've had to change out the cam seals, but hopefully all the troubles are behind it now and were cheap and relatively easy to fix. Last summer it ran 42 at Oregon Inlet with 5 adults onboard, trimmed up and tached out. I love my little 170!!