I have a 350 with an 8" balancer, can i swap my smaller 305 balancer without any trouble? Do i have to have it balanced or will i be fine?

Thanks

 

It will fit and work but the timing mark probably won't line up. The mark on most 305 balancers is at 12 o'clock (straight up, viewed from above and behind water pump) while a 350 is usually at about the 1:30 position, off to the side of the water pump.

 

So if i just use the timing tab from the 305 cover it should be fine?

 

Yes, you should be OK doing that. Just make sure that you don't need to do that first. Take off the balancer and line up the keyways where they reference to the crank and see if the timing lines points in the same direction on both. If they do, you don't need to mess with the timing tab at all. The timing tab is usually tack-welded to the timing cover on most stock covers, so you would have to swap the entire timing chain cover- a lot more work if the engine's still in the car (drop oil pan, undo engine mounts, etc, etc.).