2” primary tube headers on k3500

[Frank Enstein]

Based on the image it must be a 91 or older crew cab.

Since the truck is the Square body style there are quite a few headers available.

https://www.summitracing.com/search...ark-iv?N=department:exhaust+part-type:headers

 

[BigDaddy72]

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The new motor is a 496
4340 crank
H beam rods
Howards 10.2-1 forged pistons
Custom balanced R/A
Completely studded block
Custom cut hyd roller cam
225 225 585 585 on a 114
Afr 265 oval port heads
Scorpion roller rockers
Rpm air gap
Brawler 850 carb
Msd billet dist
6al2 digital box


Hp and tq numbers are a guess.

500 ish hp
550 ish tq

Nv4500

1994 k3500 crew cab
Lifted
33” super swampers
4.88 gear


Towing 4 to 5 times a year

 

[BigDaddy72]

I got a square but not this one.

Thanks sincerely for the response.

I m banging my head against the wall, this engine really needs 2” headers

 

[Frank Enstein]

I got a square but not this one.

Thanks sincerely for the response.

I m banging my head against the wall, this engine really needs 2” headers

For what you are doing 1 3/4" headers are what I recommend. Those 1 3/4" headers are fine up to 600 hp.

The smaller primaries help more on the bottom end than the 2" will help on the top. I would also recommend a single 4" exhaust for best performance.

Here are the headers that will fit the truck.

hhttps://www.summitracing.com/search/year/1994/make/chevrolet/model/k3500/department/exhaust/part-type/headers/engine-family/chevy-big-block-gen-v/drivetrain/4wd?N=department%3Aexhaust%2Bpart-type%3Aheaders%2Bdrivetrain%3A4wd&PageSize=100&SortBy=DisplayPrice&SortOrder=Ascending

 

[BigDaddy72]

For what you are doing 1 3/4" headers are what I recommend. Those 1 3/4" headers are fine up to 600 hp.

The smaller primaries help more on the bottom end than the 2" will help on the top. I would also recommend a single 4" exhaust for best performance.

Here are the headers that will fit the truck.

hhttps://www.summitracing.com/search/year/1994/make/chevrolet/model/k3500/department/exhaust/part-type/headers/engine-family/chevy-big-block-gen-v/drivetrain/4wd?N=department%3Aexhaust%2Bpart-type%3Aheaders%2Bdrivetrain%3A4wd&PageSize=100&SortBy=DisplayPrice&SortOrder=Ascending

I have to disagree with you on this one.

I understand your idea but in an application like mine with the afr head a 2” primary is going to out perform a 1 3/4 tube all across the entire curve.

My question really isn’t weather I need a 1.75 header or a 2.0 it’s more along the line of is there anything off of something else that bolts up in the k3500 application in the 2” diameter tube

I do understand what you are saying and I appreciate your help truly I do.

I built this engine trying to wring out every last ounce of tq and hp I could get with the combo. The engine even has a crank scraper and windage tray along with a set of total seal piston rings.

For me every last once of power I can get out of it is important, short of custom building a set of headers.

If it comes to that I will strongly consider it.

 

[MrPink]

https://www.summitracing.com/parts/hok-7525-1hkr/make/gmc

2" primary tubes 4wd fit. they however are for a square body

 

[618 Syndicate]

As I understand it, bigger primaries help a motor breathe better at higher rpm. Horsepower.
You need grunt down low to pull. Torque.
I'm also not sure what's going on if a 454 struggled to pull an empty 28 foot trailer, that's not a healthy motor.

 

[BigDaddy72]

In a stock application 1 3/4 is fine but with the head compression cam and cubic inch it needs a 2” primary tube.

It’s a dyno proven fact.

However put what ever you want in whatever you like.

My question was... Does any know of or have a set of 2” primary tube headers in a 1990’s k3500.

Sorry to burst your bubble but 230 hp and 385lbs of torque doesn’t move a 30’ box in a 9,000 lb lifted 4wd truck very well.

It slows down to 45-50 mph up a moderately incline.

I do appreciate your input it’s just not the question I originally asked.

 

[RichLo]

I dont know what to tell you besides get a set for a SqB or 2wd and do some self-clearancing. With that setup I would be looking for the largest primary also!

You have probably already seen the engine masters episode where they beat headers into spaghetti and didnt lose that much power.

 

[BigDaddy72]

Thank you Mr Pink. However I have a square with a 2” primary header the frames are considerably different.

I’m 99% sure those won’t fit, but I sure do appreciate the input.