5 cylinder GM ATLAS 3700 build

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A week or two ago, I began an engine and transmission project, thinking there may yet be another rip snorter in my future. Maybe a B210 or maybe a Roadster? I bought a ATLAS 5 cylinder engine, it's a 3.7, or 3700 cc inline 5. lengthwise about the same as a 2000 roadster engine, but yes it is taller. Like my 4200 it is all aluminum, 4 valves per cylinder, dohc, with VVTi on the exhaust cam. I additionally got a 4 speed automatic for it, a GM "4L60e", that is a lock up setup, where there isn't a lot of slush and stuff. I have already gotten some parts for the 3700, and I will post updates on here.

FindEngine Parts

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I went ahead and worked on the 3700 today. I removed the balance shafts, and used the Badlands Industries delete kit. I then cleaned up and re-sealed the rear plate, installed the flex plate with a few bolts in case I want to do a compression test later, and then got it on the engine stand. Int he pics you will see the 4 speed automatic trans for it, a lockup unit GM "4L60e", that I will rebuild with all the tough parts and probably a 3000 RPM stall, unsure at this point. PICS:

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Some of the parts I have gotten for the 3700 engine project so far.

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10-04-2026.  I took some time today, and went ahead and removed the wiring harness, the intake manifold and some other parts bolted to the block. The stuff still attached, all the bolts are now broken loose and will be easy to deal with as we go.  The parts I removed either got tossed, or put into a pile.....I then cleaned them up and took a couple quick pics.  Engine looks a lot smaller once you get all the "junk" off!  PICS

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10-07-2026.  I had a few moments today, So I took some measurements to get started on the DMZ intake DIY kit.  Because of the intake, the original alternator location won't work, So I will make my own bracket and move it down to about the halfway mark.  Plate steel or plate aluminum, M10X1.5 all thread screwed in to the threaded holes there, and start drilling holes and get it on there, and then slot holes as necessary to get belt alignment just right.  PICS:

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10-08-2026. I got the driver's side cleaned tonight. The oil pan and valve cover will be cleaned off the engine. One step closer to paint!

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10-10-2026.  I finished cleaning the block and then painted it silver with engine enamel.  Then I pulled the valvecover off, and did an initial cleaning on it.  PICS:

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10-17-2026 More ATLAS 5 banger work today. I went ahead and installed the new starter, and water pump. Cleaned up the bolts to make it look nice when assembled, water pump pulley on and then I got the crank pulley cleaned up and painted. I got the new alternator mounted on a handmade bracket using 1/4" aluminum plate.....doesn't look real good right now, as my Angle grinder died, so I will go back and clean up the bracket so it looks better but real progress on it today. The nuts used as spacers will be filed up and made to look better also. PICS:

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10-23-2026.  I ordered 2 idler pulleys from Amazon....they arrived, very nice, but the hole was too large.  So, I took them to Ace Hardware, and got some Bronze bushings.  I tapped them in, and then got bolts to bolt them up.  Pretty cool.

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10-24-2026.  I had to redo my alternator bracket again.....just move it down to make room for the intake.  I brought home the tack welded piece from my fabricator to do so, then it goes back to be finished up.  I also installed one of the idler pulleys, and got it lined up.  It takes time when you are fitting and lining things up.  In the pic below, you can see where I had to do a couple of notches to get things to line up.  PICS:

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10-27-2026.  After bringing home my 5 cylinder 3700 intake for a quick trial mockup, I got it back to my fabrication shop with the plenum ready to be finished up:

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10-31-2026. 5 cylinder ATLAS update: I began the process of drilling out and removing an exhaust manifold bolt that was snapped off by the wrecking yard before I got it, so I got started on it but then took a break, as the drill bits I have aren't cutting it. I went ahead and finished painting up the power steering and tensioner bracket, and mounted it up, then made a small plate to cover an EGP port on the side of the head. Then I began the process I did on my 4200......use the power steering bracket to mount a plate with a hole in it to mount an idler pulley. Tuned out pretty good! A spare socket made the perfect spacer for belt alignment too! The alternator bracket I had made really needed a coat of silver so I got that done as well. The early part of the day was spent doing brake work on the ATLAS Z.....bleeding things out. PICS.

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11-05-2026.  CHANGE OF PLANS.  I am no longer going with the 4L60e automatic transmission.  I got a 5 speed AR5 manual transmission for this build.  62K original mile unit inbound. Just couldn't get excited about the auto no matter how modified I was going to build it.

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11-06-2026.  Today I picked up the intake and fuel rail and thermostat housing.  I then dropped off the intake to get powdercoated in "polished aluminum" finish.  The fuel rail, work was simply turning and refitting the pipe to work better when hooking up the fuel line.  Thermostat housing was for clearance.  PICS

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11-07-2026. Today was devoted to just the valve cover.  I cut off all the tabs and brackets not needed, then trimmed off some of the "stubs" for wire ties, etc. and drilled out the 2 back breather ports for weld in female threaded -10 ORB fittings.   I already have the screw in fittings, so that will be great.  I also went ahead and drilled out the back portion for the oil fill bracket.  To do this drilling, I had to carefully remove the baffles, which are VERY thin aluminum.  I then chopped off the factory oil fill port ont he front chain cover and ground it down flush, and then took a piece of aluminum I had and made a plug to fit.  Everything will now welded up, sanded smooth, and then the cover will go for a complete polishing at J&S Polishing in Colorado Springs.  I had planned on cutting the chain cover potion down, but after taking measurements, the clearance is needed, ....I needed what was there so it will stay at this height.....it is different, as with the 6 cylinder cover, I had to take out approximately 3/4 inch.  Progress pics follow. Cheers!

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11-08-2026.  I finally got the broken exhaust manifold bolt out, got the new studs installed and then got the turbo header from Forever Fabrication mocked up on there, and re-clocked the Turbo and have it mocked up on there as well.  PICS.

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11-11-2026. I Picked up the intake for my ATLAS 5 cylinder turbo build from the powder coaters. it is "polished aluminum" color .

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11-13-2026.  Today I picked up the valve cover from my fab guy.....he got it all welded up and sanded down the timing area where the oil filler plug was welded in.  I already dropped it off at J&S Polishing here in Colorado Springs for a sanding and polishing up to near perfection.  We move forward with the rest.  PICS.