What headers for 7.4?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Dan_Frisbie

OBS Enthusiast
Joined
Nov 22, 2017
Messages
61
Reaction score
47
Location
Milton, FL
Having put dozens of sets of headers on vehicles in my time, I can state with some authority that if price is your deciding factor, stay with the stock manifolds.
A cheap header is usually not designed or constructed well. You won't gain any horsepower, it will leak, flake, rust, crack, and need replacement in a year or two.
Spend the money to buy a well designed set of headers from a reputable manufacturer. If you're lucky, the fuel savings from the exhaust and all the other modifications needed to make proper use of the headers will pay off in 10-15 years...
 

Dinkster

Newbie
Joined
Mar 8, 2019
Messages
24
Reaction score
4
Location
Reno, NV
Im wanting to buy headers for my 1996 k3500 crew cab 454. Im wanting to spend no more than $300. Im thinking about running true duals. We dont have annual emissions in michigan so not real worried about that. Anyone have ideas on what headers to get? Im lifting the truck and puting at least 38's tires on it so i want a cool sound

I swapped a Vortec 7.4l into my 95 K2500 TBI and was able to use the old TBI exhaust manifolds so I imagine the headers would work as well.
 

Crazydavez28

I'm Awesome
Joined
Feb 12, 2018
Messages
109
Reaction score
47
Location
Kansas
I found a set of the hookers at a swap meet for the TBI 4x4 454. Fitment is great on my 2000 K3500 truck. You can get some weld in O2 sensor bungs and put them straight up about 3" from the collector. Use a 1/18" hole saw and non-foulers to hold them while welding. You can use the egr fitting out of the exhaust manifold (JIC -14 Male IIRC) and weld it into the bend on the #5 primary. I have pictures but I have to reduce the quality as the files are too big to upload at the moment.

The paint that comes on the headers is junk anyway so I did a test fit to locate everything then welded the bungs on. Then blast and paint them you will be happy for around $300.
Hooker Competition Headers 2461HKR
id like to see pics of the egr and o2

You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach
 

Beeffajitas

OBS Enthusiast
Joined
Feb 24, 2014
Messages
58
Reaction score
15
Location
South NH
Anyone use the Stainless Works long tubes for the 8.1L? They are designed for a GMT800, but I’m curious if they would fit the GMT400 frame.

You must be registered for see images

Supposedly the 8.1L exhaust bolt pattern is the same. I have a GMT-900 3/4 Suburban, which is supposedly the same chasis as the GMT-800 and the front end is basically the same as the GMT-400 (same front diff, A-arms, etc). I haven't measured anything or held parts up to each other, but it's really close. Having said that, I don't know if the 8.1 sits in the frame differently.

If someone wants to chip in the $1200, I'll give it a shot!
 

Schurkey

Supporting Member
Supporting Member
Joined
Jan 14, 2018
Messages
10,970
Reaction score
13,755
Location
The Seasonally Frozen Wastelands
Supposedly the 8.1L exhaust bolt pattern is the same.
It IS the same...but with metric threads in the cylinder head. Buy metric bolts of the proper length, and the headers bolt right up.

I don't know if the 8.1 sits in the frame differently.
The 8.1 is based on the tall-deck version of the big-block, similar to the old TRUCK 366 and 427 engines.

Therefore the headers are raised up, and apart by the difference in the deck height between the 454 and other passenger-car 9.80 inch deck height blocks, and the TRUCK 10.2 inch deck height block.

.400 is enough to cause problems with some but not all headers. Kind of a crapshoot until you trial-assemble the deal.
 

ZRoe

I'm Awesome
Joined
May 7, 2018
Messages
139
Reaction score
89
Location
US
Glad to see I am not the only one searching for this answer, love the pictures from CazyDave.

I actually picked up a set of Banks Torque Tubes for a 8.1l motorhome last year for $100. I figured at a worst case I could re-sell them for a profit.

I'm working on getting the AIR pump lines out of my factory manifolds without breaking anything and then I'll throw them up to see how they fit. I had read in another thread that the P-30 chassis stuff won't fit the C/K chassis, but no real description about why not so I'll give it a try and let you all know.
 

J-iron

Newbie
Joined
Oct 7, 2018
Messages
5
Reaction score
0
Location
Gladwin,mi
I ended up finding a new pair of Hooker Comps on facebook marketplace for $100. I fitted them before i pulled the 454 for restoration. I got the frame painted and getting ready for a aftermarket cam,stall,lift, etc and a set of 40's...hopefully all that by spring
 

bobby v

I'm Awesome
Joined
Jan 6, 2019
Messages
345
Reaction score
381
Location
lake havasu city AZ
Mine had the Edelbrock 1 7/8" shorites on it when I bought it, they appear to be a good fit, performance wise I havent a clue. But having bought Kooks headers for my late Corvette I gotta say finding any header for $300, new that is, aint happening, used will be your best route.
My truck gets lots of approval on sound BTW, its 3" single to the rear with a Flowmaster 40, a little loud thou
Bobby V

PS Sorry I see you bought some already, so disregard this post
 
Top