This thread is for the general discussion of the item 1990 K5 Duramax Blazer (BroDozer). Please add to the discussion here.
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
1990 K5 Duramax Blazer (BroDozer)
- Thread starter Fancy
- Start date
LB7 Duramax and Allison 1000 5 speed in a 1990 Chevy K5 Blazer
Disclaimer: I don't get much time to work on this project so updates will most likely be slow but i will do my best to document the build and my findings for anyone interested and answer any questions.
I’ll watch!
How many miles on the Lb7 truck?
How many miles on the Lb7 truck?
Donor truck was a 2003 Silverado LB7 with approximately 280,000 miles on it and a blown head gasket. Initial plan was a complete engine overhaul but due to time and budget i will inspect bottom end and probably run it while investing in other aspects of the project. I'm only shooting for 500 HP to start.
Project started when i began my move to Reno NV, 2 years ago. 30 miles from my house the truck suddenly began to run rough and quickly started smoking. Upon pulling over and getting out to look, i stuck my head in under the fender and was greeted by a sudden burst of flames on the passenger side. Luckily i was able to retrieve my fire extinguisher and put it out. After opening the hood i was un able to diagnose what the culprit was except that oil was puking out the dipstick tube. It was assumed a cracked head or gasket at this point as both the coolant and oil were discovered as having become very close friends when drained and thus open heart surgery began last fall after the move and work had settled down.
Right on. Should be a fun project.
We got two Lb7 trucks. Both with similar mileage as yours.
Mine needs a injector and my sons needs headgaskets.
I’ve done the head gaskets on the kids before with studs but I never got the heads checked. Probably why they went again. Oops! I’ve had that engine apart 3 times now.
Once for the gaskets once for injectors and once for a reseal on the injector cups.
We got two Lb7 trucks. Both with similar mileage as yours.
Mine needs a injector and my sons needs headgaskets.
I’ve done the head gaskets on the kids before with studs but I never got the heads checked. Probably why they went again. Oops! I’ve had that engine apart 3 times now.
Once for the gaskets once for injectors and once for a reseal on the injector cups.
That sounds like a lot of work!
Ya i figure it should be easy since i got the motor out anyway. My buddy is pushing me to swap over to the LLY heads since i'm here. Says they flow better and will make injectors easier in the future.
I don’t think there is much time saving between the two but getting rid of the injector cups would be worthwhile.
Definitely would be nice to work on the engine with it on a stand.
Definitely would be nice to work on the engine with it on a stand.
Original plan was just building a hopped up crate motor. Was in the process of going the rebuild route till we found the culprit. Cracked block. It was at this time the donor truck fell in my lap. I have always wanted to do more of a full resto build anyway and wanted something different. I would have slapped the next person who told me to put an LS in it. HAHA not knocking it just seems like the go to answer and oddly for a lot of guys whom have no idea what they are taking about IDK
That sounds like a lot of work!
I can't remember if you can just switch heads or not, there certainly have to be some tuning things as the injectors are different. Having owned an LLY Dmax that I had to do some work on as well as helping do injectors in an LB7, the LLY is hands down easier to do injectors, I had one I replaced in my garage in like :45 min one night. I even carried a spare and the tools to replace one on the side of the road. Obviously some were easier to get to than others but it was just that simple, we all know about doing LB7 injectors.
From what i understand there is some slight modification to harness, ECM programing and plumbing. All of which i am doing anyway with the swap. So if that is it then i will probably go that route but i am by no means an expert on the subject just yet LOL will have to cross that bridge when i get there but that is good to hear.
After a lot of deliberation and researching i decided to go with Lizard Skin on the fire wall and under side. This is a three coat application that takes some time. First coat is the sound deadening and easiest to lay down then the ceramic and is the hardest in my opinion and then the top coat which is just an aerosol can. It took a bit of getting use to how to lay it down and having a compressor that could keep up was a BIG part of it. I am ultimately happy with how it looks over all and we will see how well it performs and holds up. I will be continuing to use this on the inside and other areas as well.
Last edited:
I then started on my custom frame boxing kit i made that runs from engine crossmember to rear forward shackle mount and crossmember. I elected not to box in the front of the frame as this is already supported in other methods were weak meaning the work would not yield any benefit to me. I used 1/8" thick plate to match the frame and dimple died it using a 3 1/2" dimple die so that i can still run lines through the frame and get my hands in there to work. Plan is to weld them in and the grind it to look like one piece.
I'm in to see how you shoehorn that monster into a squarebody.
What's the plan to make it fit?
What's the plan to make it fit?
Glad you asked! haha I am just about to post the initial test fit pictures! stay tuned
Me too, when I pull out the LS one of these are going in.
From my research, one of the most challenging aspect to fitting the behemoth of an engine was the engine crossmember. I went with the engine mount kit from precision fabrication plus (linked below) which gave some flexibility as to placement. I also already had the small block crossmember from ORD (also linked below). From another project i created frame braces on both sides where the engine crossmember bolts up. This gave an extra 1/8" of depth to the engine crossmember. Upon initial test fit I elected to run the upper engine mounts in position 2 which moves the engine forward approximately 2" as i was looking for firewall clearance and am going to run electric fans. With this i found i was about 1/4 - 1/2 " away from fitting before i hit the crossmember. I then ordered the big block crossmember from ORD which was said to give another 3/4" clearance. During the second test the clearance in elevation was perfect in my opinion but the crossmember was only about 1/8 - 1/4 from the lower oil pan which would have made removal a challenge but doable. I needed to move the engine back by about 1". I then noticed the lower engine mounts were off set to the front. I then switched the driver and passenger lower mounts and the engine now sits perfectly in my opinion. So much so that it almost loos like it was specifically designed to do so. Pictures are of the final resting place for the engine.
https://precisionfabricationplus.com/
www.offroaddesign.com
https://precisionfabricationplus.com/
ORD Homepage
www.offroaddesign.com
That looks really good, keep posting updates please!
I will do my best! unfortunately this is about were im at in the project so it will be awhile before i get some more updates.
Next will be cleaning up the frame and prepping to put it all together.
Knowing how tight the up pipes and downpipe are on stock d-max equipped trucks it sure don't look like there is a lot of room for either on the Blazer.
The driver side head looks like it's right at the firewall from the angle of your pic.
Good progress though.
The driver side head looks like it's right at the firewall from the angle of your pic.
Good progress though.
