Found out today I have a 2 piece head bolt. So truck is parked for now and i found a new long block for 3k. Ideally if im going to swap the motor I want to build it prior to. All supporting mods aside whats the best set up for a vp44 truck? I know we tap out around 700 hp which suits me fine. I think I would like to do a cam and cnc ported head. I dont plan on exceeding 3500 rpm so do I need valve springs? Fire ring or o ring ( compunds are probably in the future) what else am I missing should I step up to 14mm head studs?

Myself I'm at about 500 HP with my mods.

• ARP 425 studs

• Stock HX35W (54/60/12)

• 150 HP injectors (popped at 320 bar)

• Quadzilla adrenaline with custom tune

• BHAF

• 4" muffled exhaust Diamond Eye

Just remember more power is going to shorten the life of the engine. Even with my setup I run only level 3 of the Quad. Yeah I've gone to play wide open but could get hot. Several trick to push the power out. One of my previous tune could fry all 4 tires on dry pavement. Make sure your final ratio is near 3.73 after tires. Then don't run wide tires you'll lose traction easier. This is why I run 245/75 R16 tires. Lower rotational mass, easier to accelerate, better traction over wide face tires. Dually is even worse.

It sounds like 500 is going to be a good goal for me as well. I hate to take this long block apart so I think I'll run it how it is. But im still pending a quote from the machine shop to install o rings port the head and lap the valves. But I ordered a towing cam from Hamilton a new exaust manifold and a set of headstuds. I will gasket match the exhaust manifold (and wrap it) and the exhaust head. I think I'll still run the stock valve train (no plan in exceedingthe stock 3200 rpm) anything else I should upgrade or change while the engine is out?

If you stay to the 3200 redline then you should be safe. 12V engines only had 45 pound valve spring IIRC. 24V valve train is pretty solid 60 pound springs but I would have the guides and seals done for sure. If you boost is still lower than your spring pound rating should be fine. The closer you get boost to the pound rating on the springs more chance of valve floating then remember your drive pressure vs turbo housing size. (Flow...)

I do think I will convert 1 of my boost gages to monitor drive pressure. By doing the guides and seals are you referring to upgrading the valves and seals or just redoing them back to oem spec?

Basically when you get 300k miles on your Cummins engine typically they develope a condition called head curl. The ends of the head start to lift. This is why the head studs. Now about 300k miles you notice oil usage and that is caused by valve guides allow the valves to wobble which in turn wears the valve stem seals.

Drive pressure gauge really doesn't need to be in the cab per se if you can design and test the first time drive pressures shouldn't really change unless other things change. (injectors, tuning, etc).

I stayed down around 500 HP for a few reasons. One not willing to give up my exhaust brake yet. Smaller turbos spool faster than larger turbos. Remember the lighter the rotational mass (turbo wheel, tires, driveline, flywheel, Etc.) ther faster it will accelerate. To this day I hunt for oversize tire truck with a lift kit and whip them in a street race because of all the rotational mass. Just food for thought.

That head curl makes sense I took my broken head stud into work and had one of the material engineers look at it and what he had to say was that it was brittle fracture. His suspicion was that it was over hardened he also pointed out that it broke on the first thread on the bottom so that might have been a stress riser for it. That part of the head is the hottest section right next to the turbo is. I have my turbo and exaust header heavily insulated with rockwoll. My water pump went out last week and the truck got to 240° ( immediately turned the heater on and slowed down and it quickly droped back to 195. I think this event is when it broke. As much as I hate to say it I dont think im going to buy exotic head studs again I think the temper was bad coupled with some extraneous circumstances on my end but I still dont think it should have failed. Especially since the highest boost my truck has seen for the last 3 weeks was 12psi.

Yeah that's not good. I'm going to say your right on. Getting the truck hot most likely got that head to curl some and just heat and pressure.

Sad to think a 68$ water pump is what killed this mighty cummins.

16 hours ago, yohon said:

Sad to think a 68$ water pump is what killed this mighty cummins.

Do yourself a favor DO NOT buy a Cummins water pump. Sadly, there are too many people who think Cummins is the best supplier, but actually, they are not updating part design for improvement, but finding a cheaper way to produce the product and charge you Cummins prices. I've dealt with NAPA parts for over 20 years with a low failure rate vs Cummins water pumps and thermostats.

The Napa in town just shut down a year ago. The orileys is pretty solid guys but their parts are just terrible this was actually the in house brand and it only lasted 2 years under warranty but that dont help when your on the side of the road lol.

NAPA parts ive noticed that NAPA typically will upgrade there part line based on failure rates. I just reported a fuel filter that is not big enough to hold the lid. Look in 3rd Gen for my post about this.

Had the thought today of while the engine and transmission apart should I upgrade my single disc torque converter? Transmission has had pan off upgrades done and it was rebuilt a few years ago when it was rebuilt we were in a tight spot and all I could afford was a basic single disc billet. I dont beat on the truck hardly ever tow but the transmission has always felt like mud till the OD locked up. I would think a lower rpm stall would also be good but no clue how low is good. Any suggestions on brands?

stall speed?

Should I just run the billet single?

When the trucks transmission was rebuilt a Goerend triple disk torque convertor with a stall speed of 800RPM along with a billeted flex plate was installed. My line pressure at idle is 90PSI+ and the truck has an E-brake and is setup for towing a 5th wheel with a boat behind it so having that heavy duty convertor is a must.

Did you get by without a billet input shaft? I've seen alot of fokes say you don't need them unless you do boosted launches or are pushing big power.

1 hour ago, yohon said:

Did you get by without a billet input shaft?

The input shaft is stock. I haven't gone wild with power upgrades, just enough to tow comfortably.

That is the first ray of sunshine I have heard. Is love to tighten this transmission up but for sure dont want to grenade the transmission. I'll call power driven/dap and see what I can do

Got one more problem. One valve spring has rust at the base and its rather bad. Does anyone sell just 1 valve spring? The rest are all stock and apear new. Just one looks like it got wet. Should I rob one from the old engine?

You can contact engine rebuilding machine shops in your area and see if they have any lying around or maybe order just one from them.

O Riley surprised the heck out of me by having one on hand for 5$ thank you for the help

Finally got the vacuum pump and power steering pump out and need some advice. Should I replace these units? They are both OEM and have almost 300k with no obvious leaks on them

vacuum pump i can rebuild and found seals for it.

The power steering pump makes me nervous oil in it looks like crude oil. I hate to get a reman and it be worse then I one I have. I did find a link talking about rebuilding it. But the link didn't work I also found a article on this site about hot roding the pump ( drilling out the orfice slightly) and I'll for sure do that. Any chance anyone has a working link on how to rebuild these? Or know of a reliable aftermarket pump.