Just a few tips..... If you haven't already done so get a new balancer.... NOW Slipped ring means it's on the way out, It has a bit of a bevel to it so won't go forward but will go back and eat the timing cover real fast. Not only that but the harmonics can wreak havoc with the crank and timing chain, Hence why it's called a harmonic balancer. What it really does is absorb some of the twist forces the crank sees when a cylinder fires. If you can catch a super slow mo video of an engine running the amount of twist will open your eyes, Esp. on a big diesel.
Once that's covered you can ease the base timing up about 4* over stock, IIRC that was 0 or 4 btc with timing connector unhooked (brown wire with black stripe in the area of brake booster), If it pings too much ease off.
I liked to put the TPS at idle just a bit over .5 volts, usually around .55v, Much more and it'll idle real high (ECM thinks you're on the gas).
Use a 180 degree thermostat, It'll still allow the engine to stay at operating temp, 160 is too cold and may trick ECM into running too rich mixture.
Bet the cooling fan "On" temp scared you, Some are around 236 when fan kicks on.
Sometimes they'll have a bit of a "dead" spot when opening throttle, If so see if EGR valve is opening as soon as you press throttle, There's a delay valve you can put between EGR solenoid and valve to slow the opening rate, But it may ping a bit more.
You should see 250+ horses easily.... The basic Goodwrench 350 makes 240
When you replace the diff fluid make damn sure you put the limited slip additive in it, Then run a few figure 8's to work fluid into the clutch packs.... But you probably already know that.
Whatever you do..... DO NOT leave a socket on top of intake then slam the hood. It'll pop right through. (I didn't do that but body shop mgr did)
Have fun
