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1967 DeVille convertible
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I recently suffered a catastrophic engine failure in my '67 DeVille convertible when a valve stem broke and dropped the valve into #6 cylinder while I was driving at 65 mph. Bent a rod, which penetrated the water jacket, and the valve head bouncing around in the cylinder smashed the piston to smithereens. There was also minor damage to one of the valve seats.

I didn't think my engine would be rebuildable because of the broken cylinder, so I located a rebuilder who had a 429 core and was able to build me a new long block. I got the new long block in just a couple of weeks, but when I got it I noticed that the invoice said "1964 Cadillac 429". Well, as far as I knew, all the 429s were the same, so I didn't think much about it.

Wrong.

As I found out when I started putting the engine together, there are significant differences between the 1964 429 and the 1965 - 1967 429s. Essentially, the 1964 block is a one-year-only engine. It will NOT work in a 1965 - 1967 vehicle for reasons listed below.

I called the engine builder and we soon discovered that the 1964 and 1967 engine blocks have different casting numbers, so they are not interchangeable. The 1964 block casting number is 1481283 and the 1967 block casting number is 1482586. I have returned the long block and they are building me a 1967 long block.

Maybe my research and experiences will save somebody else some wasted effort, so I will list the reasons that I know of that a 1964 engine will not work in a later model frame.

1. The 1964 engine has a rear-sump pan, and the 1967 engine has a front-sump pan. This means that the oil pickup tubes are different, and the brace on the 1967 pickup tube will not reach the mounting hole on a 1964 block. This difference can be overcome by drilling and tapping a 5/16" hole, but there are other differences that are more difficult to deal with.

2. The 1964 block has three mounting lugs for the front motor mounts, and uses one long bolt (about 4") and one short bolt (about 1"). The 1967 block has four mounting lugs and uses two long bolts. The 1964 motor mounts are about 1/2" wider than the 1967 motor mounts, so the 1967 mounts will not fit on the 1964 block at all. Also, the rubber part of the 1967 mount is about an inch thicker than the 1964 mount.

3. There are no holes in the 1964 block to mount the starter, because in 1964 the starter mounted on the transmission bell housing if the car had a Hydramatic transmission, and on the bell housing adapter if the car had a Turbo Hydramatic transmission. Therefore, the 1967 starter won't work, and the 1967 transmission would need an adapter to bolt up to the engine.

4. The 1967 fuel pump is different from the 1964 fuel pump. The fuel inlet line in 1964 was at a right angle to the pump and the 1967 fuel pump inlet line is straight down from the bottom of the pump.

5. Also, there are some differences in the design of the valve train, but the 1964 heads should still work on the 1967 block. I am given to understand that there is also a difference in the intake manifolds, but the 1967 intake manifold bolts up to the 1964 block okay.

6. There were two different crankshafts used in 1964, depending on whether the engine was mounted to a Hydramatic or a Turbo Hydramatic. The two crankshafts have different diameter flanges at the rear, so care must be take to have a flex plate with a hole that matches the crankshaft flange.

I suspect that if I had been able to mount the 1964 engine with the 1964 motor mounts into the 1967 frame, I would have found some more problems with the longitudinal fitment of the engine, transmission, and driveshaft, but I never got that far. With the 1967 front cross member being different from the 1964 cross member, the front of the engine hit the sway bar before the motor mounts were able to make contact with the cross member.

Probably a lot of the differences had to do with Cadillac's decision to change the frame design from an X frame in 1964 to a perimeter frame in 1965, and there were likely some engineering improvements made at the same time. NNC show 2.jpg
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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72,202 Posts
A real Cadillac.​ Please keep her on the road..............
 

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Go ahead, blame me. Everybody does 🙄
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Absolutely GORGEOUS drop top, cla55ic! :2thumbs:
 
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