Hey Mike,

It's me again, don't mean to bug ya but you have all the info about stuff around here!
If I purchase the JBA headers for my 99' 4.2, can I run true duals or do I still have to have the one in/two out exhaust mufflers?
On the gears like 3.55 or 3.73 and 4.10, what exactly do these do for my truck and is it called a ring and pinion set, becuase i was thinking about purchasing one but I don't know exactly what to look for in the drivetrain department.
I'm going to give you a call.

Thanks,

Jay

 

Hi Jay,

Nice to see you again!

Sure, you can run a true dual exhaust with the JBA headers installed if you want, as they are shorty style, and will simply be bolt-in replacements for your factory cast iron exhaust manifolds. We generally don't recommend true duals in these F-150's unless you have a supercharger, due to the loss in torque below 3000 rpm at any throttle position, but that is up to you, of course.

Installing gears that are higher numerically give you better acceleration and more pulling power for towing, it's common for people who are drag racing or who are towing heavy loads to install "shorter" gears like that. You will also turn more rpms for a given speed in any gear when you install gears that are higher numerically, so your cruising mpg may come down a *little* bit. We generally recommend doing your power-adding mods first, and then only if you cannot get your performance where you want it with bolt-ons, *then* do a gear ratio change. Again, that is your choice, that is just a suggestion, our recommendation, and not mandatory. Drag racers will generally do gear changes first, or very early on, while with daily drivers we suggest doing gear changes last, as for most people the performance can be made acceptable without having to do that.

I think you & I already spoke about this when you called earlier today, so I'm just giving you a brief response here.

Give us a shout if you need togo over any more details, etc.

Have fun!