mightyquickz28

iTrader: (8)

If you rev your motor in gear or neutral and it doesn't feel like it's about to shake itself to pieces, then you're probably the proud owner of a motor that was built right, with the flywheel to be used in mind. My engine builder was caught in a huge financial fight with a guy that had bilked him out of $40K in motor work and, in an effort to get out on his own, took all he could carry off to his own shop. In my case, this meant he got, "most" of my stuff. Not the flywheel. So he balanced the rotating assembly with the idea that the flywheel to be used on said rotating assembly would be 'neutral' (ie: No counter weight) in balance. No one intimated this to me. My Stock GM flywheel was a brand new one that I'd had on the prior 355 (bored out .030, but stock stroke). That motor ran perfectly smooth, sweet and strong. I had no idea that two different engine builders would elect to balance the rotating assemblies differently. So, now I have this (theoretically) kick *** 383, ported heads, bigger valves, Long tubes, big Solid Roller cam with killer valve springs........ that vibrates soooo bad at 4K RPM and above, you'd swear the crank was going to snap in half. It's scary. I'll put this flywheel on ASAP and see how if feels and report back.

mightyquickz28

iTrader: (8)

Well... I said ASAP but it sure took awhile. I actually got it installed Sept 28th(Saturday). This is where it gets strange. I mentioned the vibration I'd had from the motor from day one and I'd concluded it was because of the flywheel never being neutral balanced while the shortblock had been setup for neutral balance. Well, I got everything ready and disassembled, took off the removable counterweight from the SPEC flywheel and installed it. When getting the starter ready to bolt back on, I noticed I could see the counter weight bolt holes thru the starter hole. I put the starter on, then finished everything else and then started the car to experience the expected buttery smooth idle. Oh hell no... damn... If I thought it was vibrating BEFORE then this was a farking earthquake at idle. The gear shift lever on my PRO 5.0 shifter looked like rivet gun hammering away. I cussed, turned off the key and sat down pondering what had just happened. I thought and thought and then decided on a whim to pull off the starter and then set the counterweight bolt holes in that same place I'd seen them earlier and reattach the counterweight. I did so then started the car. Well I'll be damned. Smooth as butter. WTH? I can only surmise that the engine WASN'T setup for neutral balance. I can now rev with abandon to 7K and it's fine. I'm really enjoying the car now, FINALLY after all this time.