My original steup was a 2.5 4 cyl 89 Jeep wrangler. I am installing a 6.2, some said I could use my original tank once I removed the gas and cleaned it. Can I use the existing gas tank pump in addition to the engines pump? how man filters should I have or what kind? additional thoughts? Thanks.

Don't know much about jeeps, but I don't know why you can't usse the same tank. As for the in tank pum, it shoundn't be nessisary. The 6.2 engine has a mech lift pump driven by the cam that supplies pressure to the IP. There needs to be a primary filter in front of the lift pump and a secondary after it. It would probably be easiest to use the old style ones from the early 6.2 pickups.

I recall the diesel fuel tank cap has a pressure relief on it that a gas-cap might not.

Depends on what year 6.2 if it used a mechanical lift pump or not.

I would be concerned whether or not the Jeep fuel pump is designed (or will handle) diesel fuel and what GPH it's rated for. If it were me, I would get a sending unit for a 4.2L Jeep of the same vintage (which still used a carb), and use an in-line electric lift pump or the mechanical pump on the motor if it has it.

On the filters itself, keep the original setup which should be bolted right to the motor.