My frontier's heads are off right now also!!! You didn't say what year but if it has a knock sensor I would go ahead and replace it with new one. They are known for going out and you have to remove the whole intake to replace it. As far as cams go I'm not sure but would there be a need to retune the ECU? and do you think there would be a decrease in fuel consumption during highway cruising?
So, you should get an ECU retune to get the maximum benefits. The stock MAF system is assuming a combustion configuration. While it will pick up any flow changes for fueling, you won't be getting the best AFRs.
As for MPG... you could see an increase if you are cruising in the powerband where you pick up efficiency. The more radical the cams the less likely though, as the RPMs climb fuel efficiency just goes out the window regardless.
thanks BLOZ UP! I was kind of worried for a second there, but then I figured teh z stores disclaimer is probably a blanket statement left over from the L series, which are a lot more finnickey about cams from my experience. I am probably going to get this regrind. 131H because it will allow me to retain my stock springs and it won't be too wild, as this is still in a truck. no need to build a high rpm monster, haha!
I think a retune would make it run optimal, but without it, being a MAF system, it will still put out more HP because the MAF is measuring air coming into the engine and giving it the required fuel. My xterra is a 2001 and I am going to lightly port/port match the heads as well.
I got my ideas from this article. pathfinder build They supposedly picked up 4mpg on the highway, even while towing!!!!
I mean, if you're getting cams I would go as wild as you can. It's a pain to switch them, IMO. But, up to you!
I also ported and polished my exhaust ports, combustion chamber, and ported the intake as well.