Factory 327 engine

[66Submarine]

Paint on the main caps and they have been numbered with a punch...absolutely a rebuild. Grinding on the crank was not done by GM...

[Classic v6 GMC's]

Originally Posted by ryanv70c10

Factory small journal rods had 5/16" rod bolts. Those appear to be 3/8" from the pics. What size socket fits on the nut?

1/2 inch socket

Originally Posted by Brad54

Some of those pictures almost look like the crank counterweights were "knife-edged," which is an old racer's trick to reduce windage as the crank goes through oil.
It's a lot more crude in places than I've ever seen before, but it definitely looks like it.
That first series of pics also looks like material was missing from the side of the counterweight, like it was a void in the casting, or metal flaked off.

If it balances (which seems hard to believe), and isn't cracked, there's no reason not to run it.
-Brad

Just looked it up "knife-edged" and it does look similar on some of the counterweights.
If I decide to use it I will have it checked out.

[Classic v6 GMC's]

Originally Posted by 66Submarine

Paint on the main caps and they have been numbered with a punch...absolutely a rebuild. Grinding on the crank was not done by GM...

The factory would not have painted the main caps or numbered them? This engine was in a low mileage truck and the heads had never been removed.
Maybe the engine had a vibration and they pulled the crank and tried to re-balance it?
I would not have thought GM would grind on a crank.

We have another original 327 we will take apart in a couple weeks. It will be interesting to compare the two.

[gabbin]

I agree, they would have milled into the balance weights till it was even (true)

[60-66]

Been reading this thread , They DID paint the main caps and number them from the factory , those are assembly paint inspection markings to signify the steps were done and checked. I have a brand new NOS 327 crank I will dig out , some of the cranks even had paint markings as did rods. Perhaps Keith Seymore could explain it better. Also , this crank is NOT knife edged , that was done only in extreme racing situations and does not at all look like it was done here. I worked in an automotive machine shop for 20 years and ran the crank grinder in that shop everyday. Your crank is stock. The only explanation I can give here for the unusual looking milling is it was done to correct the balance . Clean it up , check everything, balance, clearance and re use it. If you bore the block you need to balance it anyway.

[Ken Magura]

I too have been following this thread (very interesting).
I worked in a chevy dealership back in those days but that by no means makes me an expert.
I never knew of a 327 being in an original truck until 1966, but like I said , I could be wrong.
What is the date code on the block?
What numbers are on the stamping pad?
Just curious !!
Ken

[66Submarine]

Originally Posted by 60-66

Been reading this thread , They DID paint the main caps and number them from the factory , those are assembly paint inspection markings to signify the steps were done and checked. I have a brand new NOS 327 crank I will dig out , some of the cranks even had paint markings as did rods. Perhaps Keith Seymore could explain it better. Also , this crank is NOT knife edged , that was done only in extreme racing situations and does not at all look like it was done here. I worked in an automotive machine shop for 20 years and ran the crank grinder in that shop everyday. Your crank is stock. The only explanation I can give here for the unusual looking milling is it was done to correct the balance . Clean it up , check everything, balance, clearance and re use it. If you bore the block you need to balance it anyway.

I'm talking about what looks like green overspray (also on the crank?) as if it was painted with the oil pan off. Maybe you're right...second set of pictures looks less like overspray.

Main caps numbered with a punch by hand from GM? I haven't seen that. And some of the bolt heads are also damaged (and maybe some rod bolt nuts flipped?).

IME the engines I've taken apart that had not been messed with did not look like this.

Why are we certain the heads haven't been off before? Steel shim gaskets? I just rebuilt two engines recently and used them on both.

I'm up for learning something, but I'll be surprised if this wasn't a rebuild of some sort.

[60-66]

Originally Posted by Ken Magura

I too have been following this thread (very interesting).

I never knew of a 327 being in an original truck until 1966, but like I said , I could be wrong.
Ken

Ken , this 327 was out of a c60 I believe , they were available c40-c60 in the earlier years.

Originally Posted by 66Submarine

I'm talking about what looks like green overspray (also on the crank?) as if it was painted with the oil pan off. Maybe you're right...second set of pictures looks less like overspray.

Main caps numbered with a punch by hand from GM? I haven't seen that. And some of the bolt heads are also damaged (and maybe some rod bolt nuts flipped?).

.

Okay , I see that now, the green over spray, theres also a yellow inspection paint on the crankshaft , thats what " I thought" you meant , sorry. If that is over spray , you'd think you would see it elsewhere . Its on the side of the cap and on top but not on the bolt or any machined areas .

I didn't and don't see "punch marks" I see a number stamp , 2 , on the second main cap , that could be factory.

[60-66]

Heres some stamping's on the NOS 327 crank.

[Classic v6 GMC's]

Originally Posted by 60-66

Been reading this thread , They DID paint the main caps and number them from the factory , those are assembly paint inspection markings to signify the steps were done and checked. I have a brand new NOS 327 crank I will dig out , some of the cranks even had paint markings as did rods. Perhaps Keith Seymore could explain it better. Also , this crank is NOT knife edged , that was done only in extreme racing situations and does not at all look like it was done here. I worked in an automotive machine shop for 20 years and ran the crank grinder in that shop everyday. Your crank is stock. The only explanation I can give here for the unusual looking milling is it was done to correct the balance . Clean it up , check everything, balance, clearance and re use it. If you bore the block you need to balance it anyway.

Thanks for the expert opinion. We are going to take our other 327 apart and if that crank looks better we will probably use it.

Originally Posted by Ken Magura

I too have been following this thread (very interesting).
I worked in a chevy dealership back in those days but that by no means makes me an expert.
I never knew of a 327 being in an original truck until 1966, but like I said , I could be wrong.
What is the date code on the block?
What numbers are on the stamping pad?
Just curious !!
Ken

The 327 was available in the c60's
The numbers on the pad are
F0310U

Originally Posted by 60-66

Heres some stamping's on the NOS 327 crank.

Looks like the same stamping's.

[60-66]

Heres another 327 crank with the first counter weight milled off similar to yours . Notice yours is drilled twice for balancing in the same area plus milled on that side. I really feel it was all done to correct the balance on that engine. The crudeness is unusual looking with the burnt look , possibly done with worn tooling at that moment or in haste.

[Brad54]

Hey 60-66, just curious if those 327 cranks you have are large or small journal?
-Brad
(Sorry to hijack the thread)

[60-66]

Hi Brad. Both shown are small journal . I do have a large journal also.

[Classic v6 GMC's]

Originally Posted by 60-66

Heres another 327 crank with the first counter weight milled off similar to yours . Notice yours is drilled twice for balancing in the same area plus milled on that side. I really feel it was all done to correct the balance on that engine. The crudeness is unusual looking with the burnt look , possibly done with worn tooling at that moment or in haste.

Thanks for the pictures. It does look similar.

[jayoldschool]

I feel bad for providing misinformation

[Classic v6 GMC's]

Originally Posted by jayoldschool

I feel bad for providing misinformation

Don't feel bad. I created this thread to see what people thought about this crank. We are all learning here.

[66Submarine]

I'm figuring the "2" on the main cap is a mark someone put there when they took it apart to mark it as the #2 main cap. Considering everything as a whole, I'd guess it's been apart before...just kind of looks like it IMO/IME. Pictures could be misleading, though.

As was said, pull some bearings and see if they are original...I'm curious.

[Classic v6 GMC's]

Originally Posted by 66Submarine

I'm figuring the "2" on the main cap is a mark someone put there when they took it apart to mark it as the #2 main cap. Considering everything as a whole, I'd guess it's been apart before...just kind of looks like it IMO/IME. Pictures could be misleading, though.

As was said, pull some bearings and see if they are original...I'm curious.

I will pull the bearings this weekend and post some pics.

[Ken Magura]

I learned something from this thread about the 327 truck engines being installed in the larger trucks before 1966.
(never too old to learn !!)
Thanks everyone
Ken

['63GENIII]

Were there ever any cast 327 cranks made in either large or small journal? Ive had several 327s years ago and can't recall any having other than a forged crank.

[Bernie M]

Pretty sure 67 and older were small journal forged, 68 and up not steel they were cast. Large journal , I know in the cars for sure. Trucks?

[60-66]

Originally Posted by Bernie M

Pretty sure 67 and older were small journal forged, 68 and up not steel they were cast. Large journal , I know in the cars for sure. Trucks?

1962-1967 Car are small journal 327s . 1967 truck started the use of a large journal crank, usually forged and cars had the cast version from 1968 1969. 1967 Camaros with a 350 had a large journal crank also.

[jayoldschool]

So my 65 Impala 327 is small journal forged, correct?

[ryanv70c10]

All small journal 327 cranks were forged. Most large journal 327 cranks were cast. The hi po 327 large journal cranks were still forged. I had one a few years back in my Nova.