Will putting the cat and about 2 foot of tubing back on help with the back pressure and exhaust valve issue?
I find it very very hard to stay off the loud pedal now

 

Yes, but back-pressure is a myth. You're thinking of velocity. I really need to finish up that guide and make it mandatory for all exhaust posters to read it and take a test on it.

The valve issue is caused by the rapid cooling of the valves after the engine is turned off. The rapid cooling can cause the valve to crack or warp if it's driven for too long.

 

I had read about the valves problem because of the quick cooling and what not, I honestly didn't believe the back pressure thing for torque when I managed to smoke 31" mudders on accident on a dry road..
Then again the ol 300 has enough torque for two trucks.
But please explain this velocity or whatever.

 

It's all about pipe size and muffler design. You have to have the right sizes for a specific engine so that it takes as little effort to get all the exhaust gases out. Too big and the gases move to slowly, too narrow and the engine starts to get choked. I'll explain it further in the guide.

 

Okay thank you sir, what size pipe would you suggest for the 4.9.
The stock 21/4 or larger? I was thinking 3 inch is probably too big.

 

I don't have any experience with 4.9's, but a single 2.5" sounds about right.

 

2.5".

 

Thanks av, I really want to run true duals but I don't feel like there is room underneath until it is lifted.

 

True duals aren't possible on a I-6, only one exhaust manifold.

 

they are possible. tri y headers. basically 2 headers 3 cylinders each.

 

^ But I would still suggest a single. That 4.9 is torque monster, and a single 2.5" will keep that torque curve low where that engine loves it.

 

I already have 2 exhaust manifold, hence the Y pipe that caused this whole thread.
The dynomax kit is fairly cheap and would have good dual looks but I am always afraid of that different mufflers will sound like. The v8's are pretty much predictable but I have no idea with the sixxer. some of em sound ricey above 3 grand.

 

i was just showing punisher it was possible.

supposedly the equal length of these give a better torque curve. but they are for a toyota 2f not a ford.

 

Punisher, not to flame on you since you did say that you have no experience with a 4.9, but in 87 when ford changed to fuel injection the 4.9 for some reason got 2 manifolds, one for the front three cylinders and one for the back three. No idea why but I can't complain.

 

^ So your stuck on the duals then?