just curious... 98 ram 5.9, do these engines or any engine for that matter require specific amount of back pressure? another words will it hurt the engine to run with just custom straight pipes instead of the ol y-pipe? or for example my truck has the full factory exhaust from the manifold to the tail pipe behind the wheel... my muffler was rustin out but the rest of it okay. so i just put a cheap 18 dollar glass pack in it and put the factory tail pipe back on. will this hurt anything? heads? valves? cause them to float or something.... ive heard stuff about back pressure growin up but never really knew for a fact if that was true or not. hmmmmmm....? learning more everyday!! thanks!!

 

Back pressure is not good! You can go too big on pipes and it will lose torque and power due a reduction in velocity of the gases.
Valve float is caused by turning more RPM than the springs are designed for.

 

Back pressure and boost pressure will lower the float threshold.

However any backpressure in a NA engine will be insignificant as far as that's concerned.

 

so ur sayin as long as i keep the original diameter like 2.5" it will be okay. just dont put monster 4" front to back...correct? so even if there was no muffler or cat just pipe it wont hurt the engine? i was thinkin about puttin true duel straight back but exiting just in front of the tires for something different. prob some cheap glass pack muffler. i want a differnt exhaust but dont wanna pay the 3-4 500 dollar systems for it.

 

I've got duels and no muffler and have had it for it's entire 247k lifespan. You will be fine.

 

With duals I would use 2 1/4 inch pipes, single 3 inch.
That is with a basically stock engine.