i went 14.9 with a tune and good air, on a npi engine. stock converter, and stock 3.27's
Yeah, and I'm Santa Claus! You are full of it with only those mods on an NPI! You only ran what on a PI motor combination after that? Come on Keith.
Tony, as Trunk Monkey spoke you will need the additional pieces to really make the PI engine work well. That is the converter, gears, Maf, good Dyno tune, adjusted shift points and lock up schedules, exhaust, JMOD, and good tires for the track.
It is the combination of parts and learning how to run the car on the track that will make the difference, as well as track location and conditions as others have mentioned. The likely hood of High 14's are possible but like the others I'd be more likely to anticipate low 15's, especially on street tires and 3.08's.
The stock PI engine with the added components listed could easily put you in the low to mid 13's with time and practice on race tires. Stock NPI's with the full contigent of bolt on's, tunes etc have gone as low as 13.9-14.2s as Johnny Langton, mine, 95LX and maybe a couple others have done in the past.
For example, I know of one particular car in our group with just a PI swap no tune and street tires that has gone a 14.8-9 with basically no other parts or tune. On the other hand I have a 95 XR7 Stock, 120K miles with a stock 95NPI (120K+ miles) with underdrives, tune, 3.73's's, K & N, 70 MM TB, Otherwise stock that has gone a best of 15.0 with 27" drag tires. It might run 14's with shorter tires but it is what it is.
I hope this information is useful to you. Good luck!