Built 4.0l and emissions

[Crimsin]

I did a search but came up with nothing, so if anyone has an answer or info that would help. I called my mechanic and asked if he rebuilds motors, he said yes, but only stock motors. He would not put a hotter cam or ported heads on my motor, he said it would cause problems with emissions. Is this true?

 

[RonD]

Porting wouldn't that just makes the flow in and out better so engine can put more power to the wheels and less power to sucking in and pushing out air, but bigger cam would, you are burning more fuel, which is the point of the bigger cam, and that can through off emissions, you could probably tune it to pass, but that is another type of work, not mechanics.

I am sure you must have emissions testing in your area from his comment.
He has probably had people come back after they failed emissions tests demanding he fix THEIR problems from their requested modifications.
So he now just says "I'll pass on that job".