Backstory... See reply #38 http://forums.hybridz.org/showthread...986#post607986

Is it possible to put a 305 balancer/dampner on a 350? I hear one of the small blocks are externally balanced or some such and thus the flywheel and balancer are not compatable. I can’t remember if it is the 305 or 400 that wont work with a 350. I obviously need the smaller 6.xx inch balancer and not the 8 inch I have on there now. The balancer doner is an 86 and the recieving motor is an 87-92.

As I continue my interenet search I welcome advice. (I realy suck at finding information on the net.)

 

I think you will need the 305 timing cover so that the timing marks line up. Other than they, yes, the 305 balancer can be used on the 350.

If you want some reading:

https://www.thirdgen.org/techbb2/sho...5+balancer+350

 

Good reading, thanks!!

How would one check to see if the timing marks line up? Both motors have the timing tabs mounted at about the 2 o-clock position.

Both timing chain covers are compatable?

 

If both are in the 2 o'clock position now, then it would be a direct swap over with just the balancer. If you can fit the 8" under the timing tab, go ahead and use that, otherwise, use what you need to.

The thing about the timing marks is factory 305's got the timing tab at the 12 position, 350's got them at the 2 position - where the crank position stays the same between both engines, so the timing mark on the balancer versus the crankshafts woodruff key is different (thus the need for the balancer to timing cover 'relationship').

And for future reference, the 400 was the oddball out on external balance.

 

As far as I know, this 305 (1986 with the smaller balancer) is stock, and its tab is at the 2 o-clock.

The 350 ('87-'92 with the larger Balancer) is also stock, and its tab is at the 2 o-clock.

So direct swap with smaller dampner going on where the larger dampner once was. That should leave me an inch behind the timing tab!!



Thanks!!

 

This guy Here says this...

"Your right, all the 1986 to current 1 piece seal gen.1 engines are externally balanced and take different flexplates or flywheels, they have a smaller bolt circle "3.0in" on the rear crank flange.
I thought the conversation was about the older gen.1"

Is this true? and Is he correct about the years. As I said I'm dealing with a balancer donor from an 86, and it is going onto an 87-92 so I'm on the edge of error.

Thanks

 

Yes, but that only goes as far as the flexplate end of the engine. On 86-up, they placed a weight on the flexplate, which to some people I suppose, makes it externally balanced. However, in either case, the balancer remains neutral so either way it doesn't matter.

 

Thanks!