360 engine vibration

[Danpd69]

Hello all,

I purchased a 1971 W100 that was originally a 318 powered truck, which (from the prior owner) is now sporting a 1973 360 with a 2bbl Holley. It runs reasonably well, but I have a vibration between about 1400-1800 rpm. Nothing violent, just enough to make the steering wheel and shifter vibrate. Has anyone done the 360 swap and run into a similar vibration issue? I imagine if it the prior owner had re-used the 318 flywheel that it would be far worse and across the RPM range (if you could even make a 318 flywheel work with a 360)?

I had thought it was potentially a fuel problem, but I rebuilt the Holley today and the problem persists. Any thoughts?

Thanks,

Dan

[dodgeboykim]

Hello all,

I purchased a 1971 W100 that was originally a 318 powered truck, which (from the prior owner) is now sporting a 1973 360 with a 2bbl Holley. It runs reasonably well, but I have a vibration between about 1400-1800 rpm. Nothing violent, just enough to make the steering wheel and shifter vibrate. Has anyone done the 360 swap and run into a similar vibration issue? I imagine if it the prior owner had re-used the 318 flywheel that it would be far worse and across the RPM range (if you could even make a 318 flywheel work with a 360)?

I had thought it was potentially a fuel problem, but I rebuilt the Holley today and the problem persists. Any thoughts?

Thanks,

Dan

318 Flywheel on a 360 possibly. Maybe it had flywheel Re Balanced poorly. Trial and error with some misc weight bolted to pressure plate hold bolts will pinpoint area. Once you determine amount you could weld appropriate amount to pressure plate. Just an option.

[Jim100]

A 318 flywheel will fit on a 360. It could be that causing the problem. The 360 also demands a different harmonic balancer than 318 as you may already know.

[MadMC63]

Most obviously the 360 harmonic balancer is thicker and has cast iron weight showing between the balancer and pulley unlike the 318 which is thin and smooth. The 360 flex plate will have a visible rectangular weight for the external balance whereas the 318, being internally balanced, will have no weights visible.

[Danpd69]

Thanks for all the help everyone!

Eventually I'd like to throw a big block in it, so I just want to keep this 360 going for the time being!