How do you get the most horsepower out of a 6.2?

[Breacher]

I have a question who has squeezed the most horsepower out of their 6.2? I would like to see what people have done. Yes I know I could dig through here and find it, but I think maybe we could put it all in one spot.

So I was thinking does anyone know anyone that can build an upgraded block. I do not want a 6.5 I believe there has to be someone that has seen the issues with the 6.2 but know how to improve on the original.

 

[319cssb]

Isn't there an entire section for cucv hot rodding and modifications

 

[Keith_J]

More fuel. But this is an IDI so the flame bears against a small spot causing overheating of the piston which will cause damage.
So you need more air. Easiest is a turbo but all other intake mods can help.

Cold air intake, port and polish and water injection all help with EGT. Don't expect any more than 200 HP. Exhaust gas temperature monitoring is a must.

 

[85CUCVtom]

Probably should be in the hot rodding section but I'll have a stab at an answer. The 6.2 is not a powerhouse and was never designed to be a huge powerhouse. They can be reliable and run a long life if treated well. A lot of guys add turbo kits to them but in that I personally have no experience with that. I hate to be this guy but they are what they are- a moderately reliable diesel with decent fuel mileage.

My personal thought is if mine ever decides to grenade itself, I'll put a 383 stroker crate motor in my Blazer and I'll have all the power I need.

 

[Breacher]

Yeah it probably should be in that section but not looking to hot rod it. I know it was never meant to be a massive powerhouse, but it is a reliable engine. I would like to see a stronger block.

 

[Curtisje]

I haven't done anything but there are folks who have done everything possible to the 6.2.

https://www.kennedydiesel.com/

 

[gimpyrobb]

Navistar block.

Not sure what the hangup is about a 6.5 vs 6.2 but if you want an improved block, the navistar is your best bet.

 

[Sharecropper]

Money. All it takes is money. And plenty of it. And the ability to release that large sum of money without trepidation or guilt. And an understanding wife. And a successful career. And realistic goals. And patience. And quality tools. And dedication with a desire to think outside the box.

 

[911joeblow]

Without going inside the motor:
Turn up the fuel a bit, if she starts blowing smoke you have gone too far, a light bit is OK (EGT monitoring i recommended)
Open up the air cleaner with a tall filter and even a filter top too. More air = better
A good set of headers, twin exhaust with an 'H' or 'X' pipe will help.
Add a Paradox Cooling balance kit. Gets rid of the rear overheating and brings the front up to correct temp. We have seen gains in power and efficiency plus the reliability.
Make sure you are getting full throttle (easy one to miss).

Going into the motor:
Heads - Install oversize and undercut valves, port and polish the intake and exhaust ports, reshape the pre-cups for slightly higher RPM.
Block - Install ChMo cylinder sleeves and overbore the block, build custom forged pistons, install lightweight forged rods.

Going turbo:
Add a side mount turbo kit, add aftermarket front mount intercooler, run 4" exhaust, add turbo injectors, change to electric lift pump.

Obviously this is a quick and dirty list. You can make a lot of power but like said before is comes down to dollars and time. I would do the bolt on stuff and see how you feel about it then as those will work regardless where you go after.

 

[Dock Rocker]

If you want more power your best bet is to do an LS swap.

I’m not trying to be a smart Alec. An LS swap is easy. it’s been done a million times in square body trucks and the RPM range is very compatible with the turbo 400 if you do not want to change that as well. Also the wiring is a breeze now as well.


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[ehuppert]

What I've done for power on two of my 6.2 trucks was..... 6.2's come out. Gen 1 SBC goes in! Drove my 84 C30 dually for over 20 years..... Think I've had my M1008 for over 12 years now. With 20 years of active duty service i drove enough rattly loud diesels to last a lifetime! Go figure, have to go back and fight with the VA over my high end hearing loss! (Got a complete copy of my medical records on the sly when i retired, good thing)

I know the purists are cringing, i just find the SBC's to be simple, cheap and pretty maintenance free. I did have a BBC to go in the CUCV when i first got it, but tight in the frame rails and not so friendly with the 4.56's. Decided against that

The 350 in my CUCv i'm doing a frame off on has been rebuilt, should be right around 300 hp, peak torque around 425 or so. Mild cam, intake, headers, etc. Nothing radical, just a work horse...

I know people just love the 6.2's, but i'm not one of them. I also realize this doesn't really help you at all! Guess i just felt like sharing a little bit! Smile moji goes here!

 

[Kwaligura]

In a half ton blazer. Put a 4BT Cummins in it. Turn it up then upgrade the axles when (not if) you break them.

 

[LT67]

Not much you can really do to the 6.2 without spending a lot of coin. Changing the harmonic balancer does wonders for these old engines. I recently changed mine and it was a notable difference in power and smoothness. Keeping the fuel system clean and working as it should helps as well.

 

[richingalveston]

The only realistic solution is a banks turbo kit. It is probably the cheapest hp gain and it is not a large gain but it does wake the engine up a lot and gives you better throttle response. The turbo helps with altitude sickness the NA diesel has. IF you spend the money on reworking heads with larger valves and polishing the intake, you will not get much out of it until you add the turbo.
The blocks can not handle much more.
The second best/easiest solution is to go to a 6.5 turbo. it is a drop in and can use a lot of parts from the 6.2. Go with optimizer for strong block.

All of the other engine swap suggestions take a lot of work and many other modifications.