hello all, i am putting a new motor in my work truck, the regular 302 5 liter, and my downpipe (from headers to cat to muffler) has a smaller pipe that offshoots up behind the motor, i found out this goes to the air pump, and is used to more efficiently burn up the exhaust for cleaner emissions

anyway, i need to replace that whole section of pipe because its all rusted out ....i found an aftermarket replacement made by eastern that does not have that entire off shoot pipe, but it does have a standard "air inlet" that pokes out of the cat, but its capped off like a universal cat

can i just use that new downpipe and have someone weld my old pipe to the air inlet on the new cat?? or can i just skip the whole deal? will my emissions be bad enough to fail.....any help is appreciated

 

You need the air injection into the cat for two reasons:
The cat needs the excess air in order to operate properly and to keep it from clogging up with crud. You may very well fail emissions without the air tube, you will certainly need to replace the cat sooner.

 

yes i would rather keep it stock anyway, so can a muffler shop weld my old air injection pipe to the "air inlet" on the new aftermarket cat? I ask this only because it looks like the "air inlet" is not gonna be in exatly the same spot as where the oem pipe had it....and i don't know if they make a universal flex type pipe thats that small of diameter etc capable of being welded...thanks

 

You need to ask the muffler shop how they want to handle it.

 

well here's the update and final solution

both walker and eastern make oem replacement cats that include the y-pipe from both manifolds.....the front and rear cats from ford have been combined into one cat, from the aftermarket manufacturers

ALSO, i found that oreilly auto parts sells a replacement flex line for the oem metal air inlet line....its made out of high temp silicon and easily clamps to the "air inlet" on the aftermarket cat, the flex line is about 10$ a foot but still lots cheaper then a custom weld job for the old metal line

problem solved thanks guys