VIN number decifering and K3500 questions

Gentlemen,
I just purchased a 1994 4x4, auto, Cheyenne 3500, 12 foot dump rack with 94,000 miles. Questions are as follows:
1. Can you decifer the following VIN 1GBHK34K0RE252958?
I would like to know the engine size and differential ratio.
2. How do I know if the engine or trans is original?
3. Did the 1994 year still use carburators or had they gone to EFI?
4. The truck needs a new exhaust from the cat back. Do you recommend OEM equipment or something else to increase the horsepower and /or gas mileage.
Thank you.

1= Us Built
G= General Motors
B= Chevrolet Incomplete (meaning it was just the cab and frame)
H= GVWR/Brake System = 9001-10000/Hydraulic Brakes
K= 4x4 Conventional Cab
3= 1 ton
4= Two door cab
k= 5.7L V-8 TBI
0= check digit (doesn't mean anything)
r= 1994
e= Assembly Plant - Pontiac East, MI
252958 - Production Sequence Number

I can't get you the drive ratio...I don't know how to tell either. I got all the above info out of my chilton's manual.

By 1994 all Chevrolet were factory EFI

Go with straight pipes and no mufflers, that's how mine is and it sounds damn good. If you want a muffler use a flowmaster 40!

To check all the options you must check the RPO codes in the glove box. I think there is a big list of what the RPO's mean at www.gm-trucks.com