Hello guys. I'm new to the board, and would like to get some input on turbocharging a 6.2L. I have searched a good bit, and found some interesting stuff, but I can't find the answer to a few questions I have. My engine is out of a wrecked '87 3/4 ton Suburban and is a non EGR J code engine. It has 88,000 original miles, and has been maintained properly. (I know the guy that bought it new) I bought a set of 6.5TD manifolds and a GM8 turbo off Ebay. I am making a custom pressure chamber to fit on my non EGR manifold. I'm tossing around the idea of intercoooling it also, but I'll save that for another day! ;) My question is what are some real world HP and TQ numbers for Turbocharged 6.2's and what is the max amount of boost that is considered "safe"? I have been closely watching the progress of another guys' build-up of a 6.2TD on another message board, and he going to run a stud girdle. This seems like a wise choice to help strengthen the bottom end. Does anybody have any dyno tests, advice, or experience with this combo that you can share? This engine is going in a '67 C-30 Custom Dually Pickup. I am going to run a SM-420 manual transmission, and a 14 bolt out of a '81 C-30 P/U with 3.42 gears that I already have. The plan is to later on get a 5 or 6 speed OD tranny or Gear Venders OD, and change to a deeper rearend, but I am going to build it with what I have to begin with. This truck is not going to be doing any real heavy towing, but I will probably pull my race car around with it some (approx. 4500# car and trailor). This truck is going to be more of a novelty item than a all-out workhorse. Any help would be greatly appreciated! TIA!

You should be able to get close to 200Hp, keep your boost under 10psi, and upgrade your injection pump to a 4911. How are you planning to operate that GM-8 turbo?

I wouldn't worry a lot about the bottom end strength of a 6.2. The blocks seem to hold up better than the 6.5's. The 6.2's weak link is the pistons. They are easily cracked from too much heat or boost or too much advance. Limit boost to 12 psi, no more than 1100 egt pre turbo. You should be able to exceed 200 flywheel hp and close to 400 trq. Banks used to advertise their kits at 207 hp and 385 trq and their fuel setting was very conservative. With current fuel you will have to run your injection pump at max delivery to make you smile or like TDG said get a 4911 pump and don't turn it up too much. P.S. there is a 4911 pump being auctioned on ebay currently. Run a 3" exhaust with as little bends as possible and either a full flow muffler or a straight pipe. With propper fueling this setup will haul ....... you might have to play with that turbo a little to get the wastegate dialed in so you don't over boost.

You mention that I will have to run the injection pump at Max delivery. I hear of turning up the injection pump, but I do know how to do it. I was planning on running the current injection pump since the mileage is so low, and it runs very good. I do have access to a '83 C-20, and a '85 D-30 M1008 CUCV. Would either of those pumps be better? The C-20 runs, and the D-30 is blown, but I can get parts off either. I want to run a pretty conservative set-up. If I can get close to 400 lb ft with this combo, it will be plenty adequate for what I want to do with the truck. I don't know if any of you guys have experience with even a N/A 6.2 with a 4 speed (granny) transmission, but I used to have one in a '86 C-30 with 3.73 gears. I loved the way that truck ran and pulled. At the same time, my friend had a '87 C-20 with a TH-400/3.73's with less miles than my C-30, and it was very disappointing compared to mine. With that low first gear and less drivetrain loss, the 6.2 just acted and responded much better than his Auto equipped truck did.

Auto trannies eat horse power! Turning up the fuel is fairly easy if you take your time. If you have an injection pump that is off of the truck it would be very easy to walk you through it. Get one in hand and I can give you a detailed version or do a search and see if someone else has done that allready.

D. Camilleri, I'll take you up on that when I get to that point. Thanks! I think I am going to pull the oil pan, valve covers, and maybe the water housing just to reseal and inspect everything. What would be your recommendation on head gaskets? I have no reason to believe anything is wrong with the original ones, but I would I be better off putting ARP bolts and new gaskets on it? I'd much rather do anything like that I need to do NOW, rather than after I get it in truck. I had thought about a timing chain too, but I may be thinking more along the lines of a gas engine which is what I have worked on all my life. A few other Diesel guys have told me that if they had a 88,000 Diesel, they wouldn't touch it. What is your input on that? Thanks again!

Since you are going to add a turbo, I would replace the head gaskets, I preffer felpro, if you are willing to spend the extra cash go for the head studs! I have always wanted to use the studs, just never tried them. For all of the head bolts I have bought the studs would have been a good investment. The main reason I say to change the head gaskets is that the premier gasket design didn't come out until around 92. The earlier gaskets used print o seal and their track record isn't very good. I would also pull the pan and inspect all of the bearings. Keep in mind that 6.2's are select fit and if you decide to replace any bearings that you want to look at the size that is stamped on the bearing. Note: it will read in mm.

Many engines had one half that was standard and the other half .001 undersize. I have replaced some with standards on both halves before because sometimes getting the .001 under is not as easily available.

At 88,000 I wouldn't worry about the timing set. They all stretch, but usually it is not enough to worry about and from what I have seen the factory chain is a true roller and many of the aftermarket chains, even cloyes are not. Plus the chains are usually stretched within 30,000 miles any way. Advance the pump timing 1 or 2 degrees and call it good.

You also might want to replace the rear main seal. Factory seals are a rope seal and I prefer to go back with a felpro neoprene seal.

Since my first 6.2 swap was into a 1970 blazer, I can tell you to expect to have to modify the crossmember under the engine. I had to cut mine out because the oil pan was much larger than the small block that it replaced.

Use the biggest radiator you can get your hands on, prefferably a 4 row or if you can figure out a way to make a stock 6.2 radiator fit.

Don't use the needle bearing pilot for your clutch, they don't last. Use a good ol bronze bushing. Make sure to use a 6.2 clutch. If you plan on using your stock bellhousing you will probably have to trim the bell housing to clear the starter. If you have a choice, use a 6.5 gear reduction starter unless the engine you are getting has a very good starter.

I know there are probably some other issues but I will wait for you to ask because CRS is taking over in my head.:grd:

Thanks again for the great info. I suspected that it may be a good idea to change those gaskets. Are the Fel-pro gaskets a little thicker than factory. I know on gas Chevy engines the factory steel gasket is about .018"-.020" compared to .038" - .040" on the composite. If this is the case, it lower the compression just slighty would be a little better anyway. I will probably go with the studs. I run them in my race car, and have alwaus been pleased with them.

The select fit bearing sizes is news to me. I'm glad you mentioned it. I've got naother 6.2 shortblock that I was going to pull down and that would have definitely stood out to me!!

I should be fine on the X member. I am using the complete front suspension from a '85 C-30. If you didn't know it, you can unbolt the crossmember with all the suspension from a 73-87 truck and bolt it drectly under a 67-72 truck. Al you have to do is drill 2 holes (some people don't even do that) and slighty elongate 2 others and it will bolt right up. I was already going to change that out to have disc brakes and a little bit wide track that stock.

I am going to modify the radiator support to use the 6.2 radiator. As I said before, I may intercool it also, so I will have make provisions for that too. There is a pretty good bit of room between rad support and grill in the '67-68 trucks, so I think I can run a pretty good sized unit.

I have a 6.2 bellhousing (same engine I got my flywheel from) so that should be OK.

Thanks again for all your help! This place rocks!! :ro)

You have several options for the head gaskets. Standard 6.2 replacement, .010 thicker for engines with decked blocks or shaved heads, or run a 6.5 gasket. I am not sure but there might even be a gasket for .030 over bore. The only reason to use the oversize gaskets would be if the top of the deck isn't perfectly flat around the fire rings. The oversize allows the fire ring to go out to a wider undisturbed area of the deck. When you get to looking at the heads, don't be alarmed to see cracks in between the valves especially on the end cylinders, as long as there are no traces of coolant deposits, just run em! I wish I knew how many heads have been scrapped because of these cracks that were not even a problem. My suspension expertise is with 4x4's so you will probably be in good shape with the way you are going. As far as an inter cooler goes, you can use a cummins from a mid 90's dodge and all that needs to be done is cut off the inlet and outlet and swap them side to side so that it clears the support on the radiator support. At least this is what needs to be done on 73-87 models, but since the frame is the same width I think it will apply to the 67 also.:grd:

I will probably go ahead and go with the 6.5 gaskets then. I may try to find a Cumminins intercooler, if not I will probably go with a Spearco. Here a few pics of my truck, the body parts I'm using, and the basic look I'm after. I am in the process of shortening the frame to the stock 127" Wheelbase of a LWB pickup, and I am going to put a custom Dually bed on it. I want the body on my truck to look to look like the white one in the last pic, except It's not going to be lowered. I have already bought new tires, I'm using black powder coated 16" one piece wheels and 2004 Chevy Take-off center caps and trim rings. They almost have a painted Rally wheel look, especially on the back. I think this is going to be very cool Retro Hauler when I get it finished!

The truck before I started sanding on it. Notice the new wheels and tires.

http://67-72chevytrucks.com/vboard/attachment.php3?attachmentid=133401&stc=1

The fleetside bed I bought for it. Very straight and solid bed.

http://67-72chevytrucks.com/vboard/attachment.php3?attachmentid=125552&stc=1

http://67-72chevytrucks.com/vboard/attachment.php3?attachmentid=125553&stc=1


Here are the stepside fenders I am modifying to give it those Dually "hips"!!

http://67-72chevytrucks.com/vboard/attachment.php3?attachmentid=131981&stc=1

http://67-72chevytrucks.com/vboard/attachment.php3?attachmentid=131982&stc=1

Here a pic of a custom '69 C-30 Dually. I want the body on mine to look like this one.

http://67-72chevytrucks.com/vboard/attachment.php3?attachmentid=110091&stc=1

:cool2: :grd:

Yessireeeee, :) I took a different street around the block from my house and found a 4x4 S'ban, very rusty, Gale Banks turbo installed locally in late '80s, also '83 crew cab 2wd with same set-up. Truck is even rustier, crate motor with bad heads(?). also for sale