Howdy all,

I’ve got an ’82 GMC Dually Crewcab that has an add-on ATS turbo. I’ve got the heads off, have had them checked and they look good. I’m ready to go back together with it, but a trip to the parts store last night has me confused.

I called ahead to check pricing and every parts store except O’reilly asked me if it’s a c-code or a J-code when looking up the head-set (gaskets to compliment head gaskets).

O’reilly said they had the set and when I got there, I noticed that it says it’s for C-code engines. I gather that I have a J-code. What’s the difference in gaskets between C- and J-code engines? Can I use the set for a c-code? Do I need to find a J-code set? What’s the part number?

Here’s what’s in the C-code “Head Set” (Which, surprisingly does NOT come with head gaskets):

The kit is # HSU 8726 (20212) [<---not sure what this number is, but it's on the box]
It contains:
16 5112 Valve stem seal
1 35271 water outlet
1 35289 water outlet
4 35357 water crossover
1 6055 air cleaner
2 91585 intake manifold
2 MB 91587 exhaust manifold
2 91599 Valve cover
8 91600 Injector seal washer
1 95761 Fuel Return O-ring
1 95786 Fuel Filter

Can I use this? I'm thinking there's, hopefully, another set that is for a j-code...can anybody help me out with that?

Additionally, I plan to use the 9128 PT Head gasket which is .010" thicker. Please give me feedback if you have successfully used this gasket on a 6.2.

Thanks,
Clem

the intake gasket will be different J-Code does not have EGR. If you have an EGR valve in your intake it is a C-code. If your intake is nice and open you have a J-Code

Use Fel-Pro gaskets. I noticed this kit does not have Head bolts either. You will need those as well.

Why would you use the thicker head gasket if you did not resurface the heads?

Ah...it's the Intake manifold gaskets that are different. Thanks for that info. At least I know that much now.

I want to use the thicker head gaskets because I have a turbo and it can't hurt to lower the CR..even if just a little bit. Basically, I figure if I'm going to the trouble of replacing gaskets...I'll make the situation as good as possible.

I'll get the bolts too...but I need to find the right gaskets first.

All the part numbers listed above are FelPro...sorry that I forgot to mention that.

Does anybody know what "Head Set" part number I need for a J-code engine?

Thanks,
Clem

It shouldn't really make a difference. The intake gaskets are different, but it shouldn't matter because as I recall the J-code intake manifold itself doesn't have EGR ports...

I would imagine you're correct, HighSierra...

However, I'd really appreciate it if someone could confirm with first hand experience.

Thanks,
Clem

If you have no EGR,buy the J code intake gaskets.A metal tab is built into the center of the gasket to eliminate the EGR function.I'll try and find the part number for you asap.

The gaskets are usually universal - the stainless EGR port blocker is insertable or removable as required.

Main thing is to make sure the head gaskets cover and seal the extra water-jacket core-hole in the early heads - prevents intense coolant leakage at the driver-side rear.

If you want to buy J code intake gaskets by themselves your looking at Felpro MS91586.They cost $13.99.I'll see if i can find the "head set" number.

Thanks all for the help...

DieselOlds, I appreciate your offer to look up that number for me and will glady use that info! Looking forward to it.

Thanks again,
Clem

I went to Federal Moguls' website, whom makes the Fel-Pro gaskets, and came up with this:

For an 1982 GMC Dually 1 ton with a 6.2 they list the HSU8726 gasket kit for the C engine and HSU8726-1 for the J engine. Only difference looks like the intake manifold gasket in the set. Both kits look to have the standard head gasket, their p/n 8726PT.

Looks like just the .010 thicker head gasket has an individual p/n of 9128PT.

The above was listed for the 1982 through 1989 years.

As a side note I have a 1991 J code 6.2L in my truck and it called for the p/n of 8726PT.

Dieselolds did you come up with the same?

Hmmm...

Strange...Tha's the same HSU 8726 that I listed above and held in my hands at the parts store...and it clearly stated that it did not come with the actual head gaskets themselves.

I'll see if the counter guy can look up and order the HSU 8726-1 for me.

I really appreciate the help folks. It always seems I'm on the receiving end of this whole karma thing ;)...

Thanks,
Clem

I usually buy the head gaskets separately and then buy an intake gasket set. If you haven't machined your heads, I would avoid the .010 thicker gaskets, they don't have quite as good a track record from failing as the standard thickness gaskets. Make sure to use new head bolts, fel pro sells them and make sure to chase all of the threaded head bolt holes in the block with a sharp tap. I also like to wrap 100 grit wet dry sand paper around a good straight piece of steel and sand the top of the deck and the surface of the heads in a criss cross fashion to make sure every thing is flat and has a good clean bite for the gasket. Finish the process with thorough cleaning with brake clean.;) Torque head bolts to 20 ft lbs then 50 lbs and then 50 lbs again and then 90 degrees.

I went to double check on the p/n HSU 8726 and HSU 8726-1 and it looks like you were correct in saying that it does not include the head gasket in this set. The Federal Mogul web site listed their Fel Pro gasket set p/n HSU 8726-1 as below:

HD - J ENG CODE
NEW HEAD BOLTS RECOMMENDED
HEAD GSKT, EXHAUST PIPE PACKING, POSITIVE CONTROL EXHAUST VALVE STEM SEALS & HEAD BOLT SET NOT INCL
USE w/BOLT PREP GRA2
USE w/INST AID RED3, BLU4, YEL5


http://cds.activant.com/C2C/C01/50/251/400678388.jpg (http://cds.activant.com/C2C/C01/50/251/400678388.jpg)
(Image has been resized. Click it for full size.)


Looks like this set has all the gaskets like you mentioned previously in your set. Head gaskets have to be ordered separately.

The 8726PT is the standard head gasket. See pic below


http://cds.activant.com/C2C/C01/80/975/388813326.jpg (http://cds.activant.com/C2C/C01/80/975/388813326.jpg)
(Image has been resized. Click it for full size.)


Hope this helps and good luck!