1973 340 issues.

[QUOTE="trigger_andy, post: 1971850737, member: 2230"
By the way, what did you mean by this '' If you think you're halfway happy with it now, you ain't seen nuthin yet.''

Many thanks[/QUOTE]

He means when you get those three cylinders working right you're not going to believe how that son-of-a-gun runs. Pull the heads clean the valves and hand lap them. You can use tooth paste if you don't have lapping compound. you got head gaskets throw back together and then try it again.
The acetone automatic transmission fluid is a neat trick. It is a lot cheaper than using multiple cans of PB Blaster.

If you pull the heads and find them to be Beyond repair for your budget at the moment why not pull the 318 heads and put on it for the time being.

Another old remedy was Marvel Mystery Oil put some in the crankcase put some in your gas.