C5 early vs late exhaust manifolds and "H" pipe
 

Hey guys, I have an 01 Z that I'm removing aftermarket long tubes and X pipe (I know, I know) and putting stock manifolds/cats/H pipe back on. There is a GM part number change for the stock manifolds and H pipe from early models (97-00) and late (01-04). I know the EGR changed slightly but am not sure about overall fitment/dimensions. Has anyone ever bolted late(01) manifolds to an early(99) H pipe? Thanks!

The manifold to mid-pipe attachment is different too. I'm pretty sure they either won't bolt-up between early and late years or would bolt-up but not seal right.

The AIR tube is what changed. With the correct matching AIR tube, you could either bolt an early exhaust and midpipe onto a later car or the opposite.

Thank you for the confirmation! :cheers:

There are actually 4 exhaust versions for the C5 manifolds and H-pipe.

'97 - '99 used a stamped manifold which was a couple inches longer, and will ONLY mate to the corresponding "shorter" H-pipe. None had the little "pup" cats on the front of the H-pipe. Main cats were two-stage, and probably not as efficient as later '02 -'04 cats. The AIR pipe on the passenger side hooked in near the last cylinder exhaust. The oil dipstick was different from the '01- '04, and bolted on differently.

The 2000 was the bastard child (I have one).
The manifolds were still stamped, but were shorter, requiring a longer H-pipe, some of which (California/Vermont only) had the new little "pup" cats on the front of the h-pipe.
The AIR and dipstick located same as the '97- '99.

The '01 std and Z changed to cast manifolds, Longer H-pipe, and all had "pup" cats. The passenger AIR pipe was moved forward near the 3rd cylinder, the dipstick mounted differently.

'02-'04 std remained the same as the '01, The Z deleted the "pup"cats from the H-pipe.

For an '01 Z easy swap back to stock, best choice is:

Any of the cast manifolds (std or Z are the same) from '01 to '04.
Non-pup H-pipe from '00 to '04.
Passenger AIR pipe and dipstick pipe from '01 - '04. (which I assume you still have).

Of course, ALL versions bolt up to any rear muffler system.

Clear as mud, right?

DG

The 2000 was the bastard child (I have one).
The manifolds were still stamped, but were shorter, requiring a longer H-pipe, some of which (California/Vermont only) had the new little "pup" cats on the front of the h-pipe.

I believe NY also had the pup cats, I bought a 2000 that came off lease from a NY dealer and they had them.

DG,

Thanks for clearing this up. You've helped a ton. I knew there were some differences but didn't know there were this many. Did I mention I pulled the LS6 and am swapping for a custom built forged 24x LS7 and trying to pass strict CA emissions? Fun stuff. Appreciate the insight 10 fold. :flag::rock: