Quick questions. Can I use a replacement 305 balancer, and my stock 305's timing cover on a 77' 350 that I'm swapping in? I take it a double roller timing chain will clear that cover as well? I've heard you have to use the 305 balancer on a swap like this in order to clear the stock belts.
Also, will I need a long or short style water pump? Thanks for any help, trying to get some basic questions out of the way.

 

You should be able to use the timing cover and oil pan. There was a change somewhere in that time period, I forget when and what it was, but as long as you use both the pan and cover from the 305, it shouldn't be a problem.

The damper will most likely be a ~2 o'clock timing mark type while your stock 305 (I believe) is a 12 o'clock type. With an aftermarket bolt-on pointer, it shouldn't be a problem. Just know what you're getting when you buy the damper (or verify TDC when you put the 350 together).

You'll need a long water pump.

 

Weren't the 305's a one piece rear main seal though?

 

All SBC's have a one piece seal at the damper.

Rear main seal is two-piece pre-'86, one-piece '86-on.

 

So I can use the pan off of my 305 on the '77 350? I've been told before that it won't work?

 

You're right, I was only thinking about the rear main seal type. '77 will be driver's side dipstick, '84 will be passenger side.