What exhaust system, specifically type and brand muffler do you have? That will determine how much of a split in duration you "need" on the exhaust side.

Also, if you're planning on getting any head work done, proportionately the exhaust side usually picks up more than the intake side - especially with "budget" porting. That means you wouldn't "need" to run as much split on the exhaust side as say the unported heads.

Converters, I agree with Orr,, around 3200 is about as loose as you'll probably want to run from a medium priced converter. You can get away with around 3600 from the more expensive ones - they tend to slip less at lower RPMs.