Engine Transmission Differential


  It's time for the engine to come out of this thing! What a mess. Whoever worked on this must have just grabbed whatever was on the work bench and screwed it in. The goofy header pipe was really confusing - it was in the way of everything. As you can see, there is absolutely NO clearance. They just bent and crushed the pipe to make it fit. Who designed this?!?!

 It was only after discussing the situation with a co-worker that he pulled up a PIC of a GTO he had worked on and we compared the two. Once side by side it's pretty easy to see the difference!

My GTO Engine Complete and Correct Engine

  O.K. The engine is out of the car (See Matt's page for the removal!). Pretty straight forward. It's on a stand, accessories removed.

  As with everything else we plan to do with this car, we wanted to enlist the help of an expert to rebuild the core of this thing. The old philosophy - "We'll do everything that doesn't take talent!"

  After talking to many, many fellow car enthusiasts at the cruise-ins, one name just kept getting recommended - Bell Motors. Tom Bell is the owner - 3rd generation to run this shop. I stopped by and explained that I wanted to get the bare engine torn down to its components and the machine work done. I also wanted to let Matt see the tear down and have Tom explain the pieces and parts as they came off - not a job many shops would want to take on. I expected the response to be one of those "Are we going to do this right - or are you going to help?" But Tom didn't even hesitate and welcomed the opportunity. Great!

Bell Motor Service Sign

  We booked a morning to bring the engine to Bell Motors and Tom tore the thing down, all the while explaining what he saw. Matt's attention span may have been challenged but listening to him on the way home he clearly learned a lot more than I thought. Perfect day!

 Tom Bell and Matt with the Engine

So here's what we have:

  Here's the existing heads. You can see that there's a tremendous amount of carbon on the valves. Waaaaaay too much gas was going into the cylinders. Wrong carburetor for this engine?

Existing Heads and Valves

  Good news is that the block has been drilled [only] 20 mils over so there's plenty of metal left. Likewise, the crank is [only] 10 mils under, also plenty of metal left.

  Researching the combination of parts I would expect to get barely over 200 hp out of this combination of parts. The production 1967 GTO (non-H.O.) came with 335 HP. I'd like to get as close to that as practical on pump gas. This isn't going to just be a repair & rebuild, this is going to be an effort to locate, mix and match engine parts to create what I want. A challenge!

  So where do we go from here? Production compression ratios were ~10.5 in the days of leaded gas. Can't hold that with today's pump gas, it would ping all the way down the street and cause every moving part to fail. Hope to get a CR of ~9.0 - ~9.5 on this one. The current heads aren't going to help, too deep. I'm going to have to go shopping for something better. Intake may be reusable. Edlebrock pretty much duplicated the production intake. Also searching for a carburetor. Anybody know where I can get a stock Rochester? Pistons, valves, etc., etc.


  After hours (more like WEEKS!) on the internet, on the phone and checking every auto shop in every town I travel to, it all came together! In the last two days I found some original 670 heads, an original '67 intake manifold (tanked & painted), and a '67 Rochester Quadrajet carburetor (overhauled and engine tested). The crankshaft turns out to be an early one -GREAT! Now we're talking about an engine!

It's definitely winter here! At home work on the GTO has completely stopped. Engine work continues as it's in pieces at Bell Motors, not in my cramped, freezing garage. Boxes and boxes of engine parts have been ordered - it's like Christmas around here with all the deliveries.

The block has been media blasted and painted. The crankshaft has been turned and reinstalled. The valves have been ground and installed.

Engine Block Painted Pontiac Blue Lots of Engine Parts! Crank installed in Engine Block

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June 2015

  After gutting the interior we decided to get the transmission and engine out of the car. While some REAL mechanics would have removed both together I decided it would be a good learning experience for young Matt to see the drive train come out piece by piece. And a transmission removal was a good afternoon project. Off we go!

  The transmission was the real unknown in this car. It was born an automatic and was converted to a 4-speed at some point. Obviously, the x-mission is not original to the car but what did they put in it???

  O.K., it's out. Now I'm looking at transmission fluid draining all over the place. This old case is one that doesn't have a drain plug. Got as much out the side as possible but as soon as the driveshaft came out and we tilted it backward the stuff started to ooze. Good news is we knew it was coming and had a drain pan and rags galore.

Matt Next to X-Mission and Driveshaft

After inspection, the transmission #s are:

  My limited research shows that the main case is out of the 1968-1970 production model. The tail piece is from a 63-65 vintage - speedo input on the left, right in the middle of the Hurst shifter - wrong side for a '67.

  The gears were grinding prior to the removal so I'm pretty sure the synchronizers are shot. Maybe not. Maybe a clutch problem or the shifter itself wasn't adjusted properly. Once out of the car the shafts spin freely.

  The Hurst shifter is good and bad. It's a performance shifter - that's good. But whoever installed it left out all the bushings! Just metal on metal for the shift! Gear stop bolts were gone. Some play in the shifter but not bad. Arggh! That'll be a new installation kit...

  This will be a long process to find the parts and rebuild everything.


  Someone up there is looking out for me. By miraculous coincidence I met a retired Army guy that rebuilds Muncies "for a hobby." He charges enough to cover costs. He was out in the country and had a garage full of Muncies and a spotless M20 sitting on the workbench - DONE. Stock gear ratios. I showed him what I had, talked about how I needed to buy a new tailpiece, main case, shifter kit, etc.

  Long story short, he offered me a swap price that was less than I could have gotten the parts for. No hassle to search and search for the parts. No time to rebuild it (and he knew what he was doing!). Needless to say, a new transmission is sitting in my garage.

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June 2015

  With the drive shaft out I looked all over the rear axle for codes to give me the gear ratio for the rear end. Nothing. Smooth as a baby's bottom. Maybe I'll see something when I can get the axle out and into some decent light. So now what? I still need to know the gear ratio in the rear end?!

  Well, Matt got the chance to learn about counting the differential input rotations for each revolution of the rear tire. Oh, and the opposite tire spun the same way - that's called positraction young man. That's good!

  After some higher level cypherin' (as Jethro would say), we figured out that the rear end has the production 3.36:1 gears. That's what it came out of the factory with.

  And after drawing out the entire drive train on scratch paper and showing Matt how gears work, I'm almost afraid what he'll say when he gets back to school and the teacher asks if anyone has ever heard of ratios and cross-multiplication. That teacher may have to be treated for shock!

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