I was wondering what the best first mods are to do?I Was reading about the denny t fuel pin and the 3200 gov spring, but I was wondering if I needed to do anything else before those two mods?

 

Fuel psi, EGT, and boost gauges.
Then read through here - FAQ/Knowledge base "How do I...?" Look here first! A.K.A. "The Sticky" - Dodge Diesel - Diesel Truck Resource Forums
You should find plenty of good info.

 

Also, it's best to build a solid foundation before you start making power. Exhaust to keep air moving and EGTs down, you might consider head studs if you're going to reach for big numbers and kill the KDP; it's relatively rare that they fall out but when they do it's a pain in the a** at best, catastrophic at worst. Bulking your transmission and brakes up a little couldn't hurt, either.

 

So far I have an after market air filter and exhaust.

 

Gauges next, then.

 

That's what I was thinking

 

Can the fuel pin and spring ruin the transmission on a automatic? I've been told the spring and pin can ruin a auto transmission.

 

, no. Not unless your transmission is already on the way out or you're doing ******* stuff like neutral drops. People don't give the Torquflite nearly enough credit.