The wife said I need to hold up on projects for a while but I was thinking about free projects with a little work mixed it. So, got to thinking about porting the exhaust manifolds. Just to help with effiency and porting out the collectors to 2 1/2" and getting exhaust runners matched. Just something I'm thinking about. Not doing it for hp standpoint but more just for effiency and trying to get the mileage up a tad if it was possible. Thanks for all who have valuable information.

 

I'm not a 100% sure, but the manifolds on my 2003 were not really "portable". It's not like the old cast iron manifolds on older cars/trucks, these things are thinner sheet metal type, with not much to do in the ways of improving flow. That's why shorty headers aren't worth much, if anything, on these trucks.

 

If you mainifolds are anything like mine, the exit/collector is not 2.5 it is more like 2.25...



Also my manifold ports don't match the head either

 

the head has a different shape to create turbulance in the exhaust flow, thats why its D shaped.

 

Yeah, that's the older style cast iron kind. Probably a little bit of power by porting those, but totally not worth much at all, especially with the time invested if he were to hand port them.

 

They are the ones off my 2004, when did they change?

 

Whoops, I just double checked and those are like mine. I got them confused with my wife's Ford manifolds, which are a clamshell sheet metal design. Sorry!

 

I have a 2002. I have an extra set sitting from a 2004 burb that I was going to port and polish. It doesn't matter on time but if its worth doing, then I'm going too since its free and wife can't complain.

Always got to tinker you know.