Thread: My Little Red Muscle Truck

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2 mpg would be about a 10% increase on most trucks so I guess to a manufacturer trying to meet ever tightening CAFE (Corporate Average Fuel Economy) requirements of the EPA, it makes sense. Never mind the long term downsides to the consumer.

Here's a crazy story that shows just how out of touch federal regulators are. When the new version of the Pontiac GTO, which was just a rebadged Australian Holden Monaro, was first sold in the US, some buyers were noticing amazing fuel mileage from it's non-DOD 5.7 LS engine on the highway. Turns out those clever Aussies had included a separate fuel and timing mapping strategy that allowed the ECU to add timing and lean the fuel mixtures out drastically ( as high as 16 0r 17 to 1!)under certain light load cruise conditions. This apparently resulted in big MPG gains, but as it turns out very slightly raised nitrogen oxide emissions. This extra pollution only occurred at these special cruise conditions and was just a very small amount over the allowable limit, otherwise the engine was clean. GM was forced to disable this feature on any existing car that came back in for service and to completely eliminate it on future models. I think it is called super cruise or lean cruise. So for a slight increase in emissions we could have been saving who knows how much gas nationally if this scheme had been implemented on all LS powered vehicles. The fuel savings alone would have probably lowered total emissions substantially. Fuel not burned doesn't pollute. A crazy example of the regulators not seeing the forest for the trees!

Ok gang. It's been awhile. With everything that was going on taking care of my mom's affairs and making a few needed mods to the Healey, it was June before anything really got rolling on this project. Of course, that’s when things started falling apart on the truck “plan”.

I have a few short updates already done and will be posting them in the next few days and hope to stay current. The project has kinda started rolling good. Maybe next year will be better than this one was. Here’s the first up date. More to follow soon.

Since the engine and transmission were important parts of the build and sitting in the way in the middle of my shop, I decided to get them cleaned up, checked out and ready to install. That’s when I discovered that the engine would not make more than about a half of a turn before stopping dead. It took much fiddling with converter bolts to get the transmission separated from the engine since I couldn’t get to all the bolts and had to take them out one flat at a time with a long open end wrench. What a pain!

After getting the engine on the stand I decided to pull the heads and get a look at the bores. Now, you know, I’m not an engine expert by any means, but I don’t think the cylinder should look like this!



Needless to say, this was a gut punch. Not only was it full of rust, but there were pits rusted in the bore deep enough that it would have to go .060 over to safely clean up. Might as well go to 6.2 pistons which would be .065 over. I really didn’t want to go that far over unless I was forced to and I thought there might be a better engine out there somewhere. Sooo, the search started for engine number two.

I had my sights set on a 6.0 or 6.2 and passed on several 5.3’s. A 5.3 would probably have done anything I needed to do, but I’m old school and wanted the bigger engine.

After several weeks of looking and calling, I found an early 2000’s 6.0 in a van at a salvage yard about 30 miles from my house. I had made up my mind that I would not buy anything else unless I could hear it run or it came with a guarantee. I have known the salvage yard owner for many years and he gave me a very good price on the engine and trans combo. It fired right up and seemed to run well. He was pretty sure that the engine had been replaced at some time in the past and considering how it ran, I had to agree. The transmission went in gear and everything seemed OK there. Good enough! The next week I had it sitting in my shop.

Shame about engine #1.. but sh..tuff happens right?

Yeah, I agree and to be expected sometimes, but the story behind this engine lead me to believe it was good and I bought it from someone that I have known for years. The 4L80 transmission it was attached to was no better, BTW. Only the case was usable. Oh well.

I used the case later in the build. The engine may get rebuilt somewhere down the road. 6,2 pistons pop up every now and then on FB. That would fix it for sure. Probably what I should have done to start with. Wait for part 2 of the engine story!

Now for the saga of engine #2!

The next engine was nothing short of filthy! The valve covers and valley cover had been leaking for who knows how long and the engine and trans were both covered with a very thick (VERY VERY THICK) layer of dirt and baked-on oil. It took many cans of engine cleaner and numerous pressure washings just to get the thing clean enough to start working on.



After getting the engine on the stand, I pulled the plugs and everything went south from there! They were covered in oil! Several cylinders were apparently shot. I did a leak-down test and never got past cylinder #1. It had over 40% leak-down! I could hear air leaking from the intake valves, exhaust valves and into the crankcase. Rings were completely wasted as well as the valve seats. Hard to believe the thing didn’t smoke. I mean absolutely none could be seen on the test run.

At this point, I was done with used engines. I decided to do what I should have done with the first engine and that was do a rebuild. Actually, I had hoped to just do a rering job, but after getting the engine apart, my measurements told me that wasn’t going to be possible. I loaded all the parts up, including a set of 799 heads, and dropped them off at the machine shop. The engine originally had 317 heads, but I picked the 799’s up on FB marketplace. The 799’s have slightly smaller chambers for a compression bump and they have the same ports as the 317’s.

I also decided to quit messing around with used transmissions and dropped both transmissions off at good rebuilder. He built me a heavy-duty trans with a mild shift kit. It took both of my transmissions to do it as the case from the van was cracked under all that gunk (go figure!) and the van transmission had a slip yoke on the output, which I needed. The original truck trans had a bolt-on flange. After talking engines and driving style, he also recommended a mild stall converter. 2400-2800 range. He said he had the same converter in his truck and thought I would like it with my engine.

A few weeks later, I had a pile of new and redone engine parts laying around the shop. Everything went together fine. The assembly on LS engines is still a little strange for me since I’m used to building old school small blocks. The alignment of the covers and the torque to angle bolts seems to slow the whole process down, but it ain’t nothing I can’t handle. My son-in-law is eager to help and a little team work made the torque to angle process a lot faster.
The specs on the finished engine are:

6.0 liter

Stock bottom end and rotating assembly with .020 overbore

Between the overbore and heads compression should be around 10.2 to 1

Cam is an older Comp grind XR265HR I had left over from the Healey project. 212*@.050

Heads are stock 799’s with PAC 2018 springs. Rockers got a BTR trunnion upgrade

High volume Melling pump since my bearing clearances came up slightly more than I like (about half thou) and I’ll be running an oil cooler

Trailblazer SS intake and injectors with 92MM cable throttle body

Speed Engineering long tube headers



My arm-chair guess tells me this should make around 380 HP at the crank and 400+ on torque installed with all accessories. It might do better, but that’s plenty. Any extra would just be a bonus. At any rate, it should have enough torque and HP to be a lot of fun to drive.

That was rotten luck on the 2nd engine & tranny after hearing it start, run and work the gears but your recovery was AWESOME! The new engine looks great, and is going to be a great fit for the truck. Glad you're back on it and looking forward to watching your progress. Thanks for being here!

I got scammed on an ebay 5.3 too (30k miles, LOL). The cylinders were full of water. I managed to clean them up with a hone and did a mild rebuild of warn out parts. Can't tell you how many times I've lost money trying to save money but never seem to learn...

Your engine looks really nice, should be a beast.