454 tbi manifold options

[Circuit Rider]

Hey guys, I have been lurking around, looking for answers to no avail. Here is the dilemma, both exhaust manifolds on the 87 454 tbi motor with AIR holes are cracked and leaking. With the oxygen sensor located on the left side manifold I feel that it is telling the computer to go lean so it is increasing the fuel causing the motor to run extremely rich. Does that sound about right?

Here is my next question: what is the best brand of manifold to purchase as far as fitment? Advance auto sells a Dorman brand but is there any other brand that would be any better or should I look for stock used replacements. Please let me know and help me out on this issue as I need to purchase soon. Thanks

[MalibuSSwagon]

I believe the Dorman manifolds are the only option available for stock replacements.

[suxtobu65]

I know you dont want to hear it. But, i recommend full length long tube headers. I did this on my 88 cc dually. Muffler shop didnt take long to modify stock exhaust to fit the collectors. I used hooker comp headers. O2 bung welded to drivers side.

[Circuit Rider]

Thanks for the replies, my truck is an 87 CC dually and I have toyed with the idea of headers but not to sure how they will work with the Cat installed, anyone have any experience with that? As of right now still leaning towards the stock manifolds.

[Desert1957]

Originally Posted by MalibuSSwagon

I believe the Dorman manifolds are the only option available for stock replacements.

The "Dorman" manifolds are a nice quality replacement. I installed a set for someone a few years back.

Also replaced my RV manifolds with Dorman, No complaints.

Desert

[GRADYS Performance]

The Dorman manifolds are good stock replacements. Headers will help the engine breathe better, should help mileage and power when you need it.

[SCOTI]

Originally Posted by GRADYS Performance

The Dorman manifolds are good stock replacements. Headers will help the engine breathe better, should help mileage and power when you need it.

My 89 CC's TBI 454 suffered the same issue of cracked manifolds & the resulting exhaust leaks.

I never checked my manifolds temps when running but I swapped headers in when rebuilding the motor. The main downside to them is increased underhood temps. Even w/my headers coated, the temps are HOT (~700°) @ the primaries when idling for several minutes. I considered the exhaust 'heat wraps' but that seems to promote rusting of the header by trapping condensate. I'm currently surfing info for some type of vent system to help give the hot underhood air a place to escape.

[Circuit Rider]

I appreciate all the input from you guys. I ordered a set of Dorman manifolds yesterday and they should be here this evening. I hope to get them on sometime this week. Thanks again.

[MalibuSSwagon]

I'm going to go with manifolds as well on my 8.1L swap. Headers can be a pain with the leaks and high underhood temps