first of all let me say good evening folks and well my question is would i need a retune if i got some long tube headers recently installed with no cats because i had shorties on before when i had the tune done . My old system was the edelbrock shorties, aem intake, true dual exhaust dynomax bullets with cats and the dyno tune and i was pushin 301 rwhp and 316lbs of rwtq. would i see a difference in #s if i did the retune since i dont have shorties no mroe and no cats?

 

Uh...yup.

 

definately would and you would also want ck eng light off if you got rid of the cats

 

Would he be ok running with out a retune for a while, or would that cause damage?

 

you'll be ok with the same tune. it won't cause any damage. you'll just get a check engine light. ran my truck for 2 months without a tune with no problems.
but again, to gain optimal performance out of them longtubes and no cats, yes a retune is needed and you will gain some.

 

after I installed my lt's I left it untuned for a good month or so I guess. Fuel trims changed a decent amount from when I had the stock exhaust compared to the lt's. after I installed the lt's i just reset all my fuel trims, that's the only "tuning" i've done since I put the lt's on and it's a big difference in power, and sound