When i was installing my FPR for the 13BT i was reading the instructions and it says to use a liquid filled fuel pressure gauge. I found them off autometer but only in 2 5/8. so i was wondering if i could have a normal gauge that is 2 1/16 or does it have to be lquid filled?

 

Are you running it in the engine bay or cab?

Liquid filled : engine bay/outside cabin
"normal": inside cabin

Liquid filled guages have other benefits than just dampening the needle. Since being completely sealed, they can withstand heat, cold, vibrations, moisture, ect alot better.

 

i want to have it right on the FPR under the hood

 

exactly the reasons i'm using a liquid filled fuel pressure gauge. i got mine from summit but, it's been far too long since i've had my hands on a 13b, so i can't help you with sizing. my car hasn't had an engine for almost 5 years