I have a 1993 GMC 3500 that is in extremely nice shape. It has a 4.11 rear diff and a 5 speed standard transmission. I am giving it to my daughter's boyfriend and we plan to replace the 6.5 diesel with another engine. I have told him the easiest option would be to put a new Peninsular 6.5 diesel in it. If we replace the turbo and fuel injection system this will likely cost around 10k. The new engine would be a 2013 6.5 tuned to I believe 300 HP.Option 2 is to purchase a wrecked 2005 Ram with the Cummins in it for $2500. The truck has 155,000 miles on it. I like this option but realize it may be quite a project. Anyone know what all is involved in doing this swap? Some things I am pondering before committing to this project are:The standard GM transmission should bolt up ... what about the clutch?Clutch linkage?Clearance? Will we need to install a lift kit?Will the transmission need to be moved back? Have to cut hole in floor board? Shorten driveshaft. Extend transfer case linkage?What about the after cooler mounting? Accelerator pedal - likely electronic on the Dodge - I guess it will have to be moved and mounted somehow?What about cold start set up? Ignition Switch?

Here is a picture of the truck:

Shop the internet. You will find several companies that sell all the parts to make the Cummins swap. They can answer all your questions. I don't think it's as easy you might think..B.O.

in one of the diesel mags a guy has a suburban or a blazer or whatever with the old diesel and he wrote in to ask about an upgrade. Said its pretty easy chebby to chebby. So that would probably be the best route for ya to go. a cummins change over based on what I have read will run pretty close to $20K once it is all done. Many have estimated $10K, but the ones that reportedly done it give the higher number.

Hank85713 wrote:in one of the diesel mags a guy has a suburban or a blazer or whatever with the old diesel and he wrote in to ask about an upgrade. Said its pretty easy chebby to chebby. So that would probably be the best route for ya to go. a cummins change over based on what I have read will run pretty close to $20K once it is all done. Many have estimated $10K, but the ones that reportedly done it give the higher number.I just phoned and talked to a guy from Montana that did one. He said it was done for around 10k. I am quickly realizing this project could easily become much bigger than I am willing to make it. Are these Peninsular diesels worth considering?

Cheapest route would be to switch it over to a gas engine. They did hundreds of them back in the 80s to get rid of those 5.7 rattlers they used...$10,000 into a $8,000 truck isn't a good idea in my book.B.O.

Motor Swap | Good Sam Community

15 Replies

blt2ski
Moderator
Nov 03, 2013
Get the new block. It is from the same factory that builds the IHC 7.3 v8 etc. So no issues with that motor.

As noted, you have a 93, so it already has teh manual injection pump. The 5 sp is the wide spaced LOW first gear. IIRC about 6.5-1 vs the 94 or 95 and later GM along with the dodge versions of the NV4500 at 5.6-1. But spaceing is a bit better. A 4.10 with this taller one is a very driveable 5 sp. I would suspect this one is a drivable 4 sp, with a really low 1st. At least my 96 CC was nice. Wish I still had it at times.

Marty
Jarlaxle
Explorer II
Nov 03, 2013
Note: the various surplus dealers have TRAINLOADS of rebuilt Hummvee 6.5's coming in! One went into my wife's Blazer...zero problems, a total bolt-in aside from the turbo oil lines & exhaust.
4x4ord
Explorer III
Oct 24, 2013
45Ricochet wrote:
Good Luck Terry. My real question though is what was wrong with the original 6.5 :W Oh wait Bob has one that is still running so they must all be good....
I think your on the right track about the cooler. Might as well do it once and be done with it.
Sounds like a fun winter project, if your garage is heated :B

The original still runs. It was going through coolant and gaining oil ... likely cracked heads. Occasionally it will start pouring white smoke out the tail pipe for no apparent reason and then clear up again .... air getting into the fuel??? (the real puzzling thing about this was that it would only do it while revving it up in neutral or first gear). I ran it for years in this condition and more than likely have been circulating antifreeze through the bearings. (loosing water and gaining oil isn't a good sign). Fortunately I do have a heated garage that can be dedicated to this project.
45Ricochet
Explorer
Oct 24, 2013
Good Luck Terry. My real question though is what was wrong with the original 6.5 :W Oh wait Bob has one that is still running so they must all be good....
I think your on the right track about the cooler. Might as well do it once and be done with it.
Sounds like a fun winter project, if your garage is heated :B
4x4ord
Explorer III
Oct 24, 2013
Thanks for the replies. We have pretty much decided to go with the Peninsular Diesel...although we still could be convinced to go with a stock 6.5. If we go with the 300 HP engine it should be capable of doing a little towing and Peninsular claims it will get he same fuel economy as the stock 6.5 did. I am a little concerned about 300 hp out of a 6.5 without using an intercooler? If we do it, we will install a pyrometer and I guess if need be we might just have to add an intercooler.
stsmark
Explorer
Oct 22, 2013
My son and I put a 4BTA from a bread truck in his YJ Jeep rockcrawler and it came from a GM chassis so it had the flywheel / bellhousing / rear engine housing for a GM manual on it. An SM 465 in this case which we modded to a 4wd tail and it works great. All the configuration parts are bolt on for a Cummins and swap between a 4B and 6B. Should be able to find them in a truck junkyard or Craigslist.

Peninsular has been around for a while and doing 6.5 engines for 15 + years I know of, so they must have a decent product. Have fun
Hank85713
Explorer
Oct 22, 2013
look for a wrecked donor truck and take everything and change it out, maybe just take cab and box off wreck and replant with yours. some fabrication required but you will end up with better running gear and less hassle then trying to transplant anything in what you have.

try to find a army surplus chebby blazer saw them going for about 6K some time back, was a guy locally selling them and then update the engine with turbo etc. still going to run about 10K, but it will be something to talk about for a long time particularly if there are young family members involved.
Me_Again
Explorer III
Oct 22, 2013
Put a nice 8.1 or 454 in it! Chris
Turtle_n_Peeps
Explorer
Oct 22, 2013
I own the exact truck you have except it's a regular cab.

I really like the Cummins deal but it has it's own problems. One being weight. The Cummins weighs somewhere around 3 to 4 hundred lbs more than the 6.5 and that is a bunch! Then there will be a lot of work to change it all over where a 6.5 will drop in, in an afternoon and be running.

I would just drop in a new 6.5 and be done with it. The biggest problem with the 6.5 is electronics and the 93 did not have those. Another problem is the iron in the block and head.........or lack there of! The new blocks and heads have a lot more iron in them. I heard good things about the new blocks and heads.
dodge_guy
Explorer II
Oct 22, 2013
I would definitely go gas. I would go with a newer 8.1L and appropriate trans. and wiring, this will last a long time! they make kits and you can send the harness in with the pcm and have the harness reworked so it is just a plug and play and 3 wire hookup and they will flash the pcm to use only the needed items and remove the theft feature.

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