Steve, my 1995 K1500 Cowboy Cadillac.

[MIHELA]

Truck runs, but AC compressor is noisy and sounds like a vacuum leak. Replaced the clutch bearing and removed part of the rear bracket to get the alignment dialed in. Found a threaded port I missed, plugged that. Still not quite right. Hmmm.

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[MIHELA]

There it is. 500 gasket doesn't fit! Bought a 368 gasket and the vacuum leak went away. Then all of a sudden the no-start condition from before came back!

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[MIHELA]

I chased everything, including redoing the wiring to the injectors and distributor that I had soldered because they weren't great. The clue finally came when I got the truck to run, very badly, at a 450 RPM idle long enough to get a datalog going and noticed that there was no RPM signal, but the tach was working. The ECM was bad. It was probably the cause of the original no start problem way back in 2018! New ECM and bam, runs fine. So I started the tuning process which is still ongoing. I will need to redo the RTV because I have developed a rear valley oil leak I noticed this week. Not nearly as much of a hassle with this manifold though, and I will do it with these long awaited shaft rockers! That way I can properly check preload and not lose any pushrods.

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[MIHELA]

That pretty much brings me to the present day. The truck runs better and better with each tweak I make to the tune. I've done light off roading with it. I've used it to haul lumber for my fence. It's not really fast but it pulls consistently at any speed. It has AUTHORITY. The last time I calculated mileage it came to 11.9 MPG across 2 tanks, even with all the manifold shenanigans in the middle of that average. The engine now has over 2000 miles on since the swap.
I need to replace the tie rods and install my GMT800 brakes as well. Then with a new set of tires, I will feel confident to take it further from home. My plans are to wire my front deflector markers back in, add some Venture windows actuators to make the rear vent windows more useful, add express down to both front windows, wire in keyless entry, and get my new rocker arms installed. I also would like to add some sort of trip computer to the roof console and build a car computer setup or android to replace the factory radio.

 

[DirtBag]

Wow....I followed this one from the beginning. Always looked forward to the updates. You have some serious skills and knowledge. Well done!

When I first went to college I drove a 1976 Cadi Sedan Deville....4 door....mint green....Had the 500ci motor......fully loaded with every option you could ever think of, including telescoping steering wheel...LOL. It was the funnest car I ever owned and I still think about it all the time.

 

[PlayingWithTBI]

Yes, a very interesting journey, thanks for that. Keep us posted on further excursions.

 

[1ton-o-fun]

Awesome build thread! A little disappointed to find that the Cad Company changed hands in 2001. The protective "don't really want to show/tell you anything till you buy something" was understandably passed on to the new owner. Website is kinda sparse and outdated. Encourages you to buy the $5 catalog for current info. -So I did, only to get a 2004 (or'05, it's not in front of me) catalog with a sticker on the envelope saying to check the website for current info and prices. --GRRR!
I DO remember enough from back in the day to know that when these engines were produced, they were actually quite amazing. High nickel strong blocks, tough as can be rotating assemblies, balanced and blue printed... best of the best.

 

[MIHELA]

I think the only reason the prices have stayed low on cores is the high price of aftermarket, some critical to fix design flaws, and the gas guzzler image in the modern day of higher fuel prices. But really they aren't that bad on fuel in reality and are built very, very well. It's basically the perfect truck motor. Hell, it's in spitting distance of the new GM and Ford heavy duty gas engines without any fancy direct injection or ignition tech.

 

[MIHELA]

I am on Version 92 of the tune, I got 11.9 MPG on the last tank and I'm far from done. I've been leaning out the cruise areas. It drives great!

 

[Supercharged111]

Better than the 454 pulls down in my dually, that one runs high 10s, but I do have 4.10 gears, itty bitty 29" tires, and 4 wheels to spin. I'd be curious to see a dyno on this thing.