368 ?s

[J-rod]

I know this probably has been answered before, but what parts (if any) do the 500 and 368 have in common?

TIA

[jerry]

water pump maybe,maybe valve covers

[Terrible One]

Yeah, valve covers will definitly switch out.

[CadillacPat]

J-Rod,
I recently completely disassembled two of my three 368's. I also have a 472 and 500 apart. I still haven't checked to compare, but the timing covers are supposedly slightly different and I don't know which will work on which.
Now the good news. The following parts are interchangeable:
Valve covers
oil slinger and fuel pump eccentric
Distributor
oil pan-IF you modify (i.e. dent outward) the front of the pan where the #1/#2 rod spins on the 368 pan it will clear for the 472/500; check final clearance with the pan on and NO oil pan gasket and you should be good to go-also, this pan will only hold 5 quarts (the Eldo 472/500 pan holds 6 quarts)
timing chain and gears
all engine bearings
rocker arms
cam and lifters
The gaskets are interchangeable except for the head, intake, exhaust and maybe the timing cover, but I think that although the timing cover itself might not interchange, the gasket will
Finally, the intake on the 368 (aluminum) will work if you port the hell out of it, but make sure you leave enough metal for gasket sealing; supposedly it will flow quite well up to about 4000 rpm. This would be better if used on the 425 because of the lower CID

[CadillacPat]

Water pump
Also, since the engines share all bearings, supposedly the 472/425/368 cranks will interchange (they all have a 4.060" stroke), but it is not recommended. If using a 472 crank in a 368 or 425, it is overkill (also, the 368/425 has smaller main oil galleries like the 68'-early '69 472). Vice versa and the crank might not be strong enough.

[STDog]

Water pump
Also, since the engines share all bearings, supposedly the 472/425/368 cranks will interchange (they all have a 4.060" stroke), but it is not recommended. If using a 472 crank in a 368 or 425, it is overkill (also, the 368/425 has smaller main oil galleries like the 68'-early '69 472). Vice versa and the crank might not be strong enough.

I'd love to know more on the crank interchange. I have a '72 472 to rebuild than needs crank work, and a 425 that supposed to run, but has been sittuing for a wile. It has 2 tight spot in the stroke, but I don't want to pull the head on it yet.

[STDog]

I recently completely disassembled two of my three 368's. I also have a 472 and 500 apart. I still haven't checked to compare, but the timing covers are supposedly slightly different and I don't know which will work on which.

If the 368 front cover is like the 425 cover, then it'll fit a 472, but a 4723 cover won't work on a 425. The block was changed. There's a hollow space on oil pump side on the 427 block tbat is cut out on the 425. Most gasket kits come with both gaskets.

While the 472 cover is straight from the oil pan top the water pump on the left and right, on the 425 there a buldge on one side. I wish I had pictures. I migh get some tonight.

[~JM~]

Hey Caddy Pat,

Do you know how much difference there is on the oil pump pick up tubes between the rear sump Eldo 368 pan & a rear sump Eldo 500 pan?

Thanks
~JM~

[STDog]

Do you know how much difference there is on the oil pump pick up tubes between the rear sump Eldo 368 pan & a rear sump Eldo 500 pan?

I cannot help there. Never worked with Eldos or a 368s :(

[CadillacPat]

STDog,
I have been busy and was out of town the last few days for a funeral.
I brought my last 368 (I had three) and 425 back from a friends house where I had them stored and will be dissasembling them. Now I can compare my 368/472/500's with my 425.
A while back on the older board, there was a thread about a member buying a supposedly 472/500 timing cover from a seller on ebay. The member was inquiring about the interchangeability of timing covers. From what I remember, the 425 timing cover will not work on 472/500's (a board member noted that he probably bought a 425 timing cover). As you mentioned, there are slight differences in the outside of the block between the 472/500 and 368/425's, the biggest difference is located on the front of the block where the timing cover mounts (also, the oil pan rail is slightly different since the 368/425's have a "scalloped" rail; however, the oil pan gasket is still interchangeable).
Of the Caddy cranks, 500 cranks are the most desirable, especially if you have a late '69-up block (which has notches at the bottom of it's bores to clear the stroke of 500 and larger "stroker" cranks).
In my collection of engines, I acquired a 500 with a bad crank (all of the rods were spun plus a few mains; obviously, the idiot who previously owned the car literally drove it until it dropped). While the rest of the engine was good (except the rods), I picked up another 500 crank on ebay for $109 (Al was out of cranks at the time, and, if he had any to sell was asking $250).
Next comes the 472 crank. Because so many want 500's, or, a 472 and put a 500 crank in it to build a 500, 472 cranks go for cheap. This is not to say they are given away, but they are usually much less. Although I have seven 500's and three 472's, the first engine probably to get rebuilt is a 472. This is because of a deal I found on 472 pistons.
Finally, I mentioned that, while a 425 crank is supposed to work in a 472, I would not advise it. If you look at the 368/425/472/500 cranks side by side (or the rods for that matter), it is pretty obvious of their size and strength. As a side note, while scrapping two 368 cranks, and throwing them into the scrap pile at the salvage yard, one crank broke at a main journal when it hit the pile! However, I think this was the crank that was in the engine I had that had about 1/4" (YES, .250" back and forth travel). The engine ran fine until it later spun #8 rod bearing).

[CadillacPat]

JM,
I have no experience with 368 or 425 Eldo pans, but I believe I read that the 368 pickup tube has a smaller diameter. Since ALL Cad engines in the family have the same bearing sizes, and, because these bearings require an adequate amount of oil flow, I would not recomment using a 368 pickup if you can help it. However, for low rpm engines, and if you use a higher volume oil pump such as Al's along with a good quailty oil (I perfer synthetic oil on broken-in engines), it should work. Maybe someone else can also offer advice.

[STDog]

A while back on the older board, there was a thread about a member buying a supposedly 472/500 timing cover from a seller on ebay. The member was inquiring about the interchangeability of timing covers. From what I remember, the 425 timing cover will not work on 472/500's (a board member noted that he probably bought a 425 timing cover). As you mentioned, there are slight differences in the outside of the block between the 472/500 and 368/425's, the biggest difference is located on the front of the block where the timing cover mounts

I'll have to look a little close, but I still think a 425/368 cover would work on a 472/500.
It might take a small mod.

Where the block was cut away, the 472 cover used a bolt with a 1/2 head (fI orget the thread sizes now) through the water pump and into the block. this is at the edge of the cover.

On the 425, the cover bulges out to match the block change. The water pump is then held by a smaller bolt (with a 3/8" head) into the cover only. The cover is held by the lower accessory bracket mounting bolt (5/8" head I think) that is now covered.

To use the 425/368 cover on a 472/500 you could drill that hol out big enough for the correct bolt, and use the 472 gasket. It migh also need the buldge section trimmed down, but I think it'd be OK. It could be cit to match the gasket incase the accessory brackets do line up.

[CadillacPat]

STDog,
I disassembled my 425 today, and compared the covers and fronts of the blocks. Here is what I found:
The 425, and the later 368 were cast with "weight saving" features. Besides the "scalloped" oil pan rail, metal was removed from other places on the block. This included the valley pan area, the main webs and the front area near the oil pump mount. For these later engines, material was removed on the lower left (looking at the front of the engine) corner of the block. The removal of this much cast iron, and replaced with a timing cover with a bulge to cover the removal, was one of the weight reductions which caused the 425 to weigh an advertised 100 lbs. less than the 472/500 it replaced. Since the 472/500 block has cast iron in the place a 368/425 timing cover would cover, it's cover won't work on 472/500's. However, the 368/426 timing cover will work on 472/500's, with a slight modification. When Cadillac removed the cast iron from the block on 425 and later engines, they also removed the lower left small mounting bolt hole (the 3/8"-headed 1/4" bolt you referred to) that was one of the bolts that mounted the water pump. Instead, the lower left 1/4" mounting bolt is now bolted to the timing cover in the same way the other 1/4" bolts are (using the timing cover hole for threads). To use the 368/425 timing cover on a 472/500, you have to grind the back of the cover behind the hole and probably also drill out the hole. Drilling the hole should be done so the attaching bolt will pull the water pump onto the cover for sealing the pump to the cover and then to the block to hold them together as one.

[STDog]

STDog,
Since the 472/500 block has cast iron in the place a 368/425 timing cover would cover, it's cover won't work on 472/500's. However, the 368/426 timing cover will work on 472/500's, with a slight modification. ... To use the 368/425 timing cover on a 472/500, you have to grind the back of the cover behind the hole and probably also drill out the hole. Drilling the hole should be done so the attaching bolt will pull the water pump onto the cover for sealing the pump to the cover and then to the block to hold them together as one.

I think we said the same thing:)

425/368 cover will work on a 472/500 block.

472/500 cover will not work on the 425/368 block.

[CadillacPat]

Yep, Yep!