Do factory truck small blocks usually come with steel cranks?

[special-K]

Originally Posted by MARKDTN

Here is some info on 327s from another post. There is no large journal 327s in 67 Chevelles and thus no 4 bolt mains.
***************
This addresses small journal 4-bolt 327s, but also 1968. Here are some of the highlights:

There is no such thing as a factory 327 4-bolt main. You can build one out a large journal block, but none were ever made factory. You will not find a single instance of anybody that can prove there ever was one. Lots of "I heard they did......" but no real evidence. There are pages on Google about this and not one of them I've seen can show any documentation that they exist.

Some have claimed this with a 3892657 casting block. See http://www.nastyz28.com/sbchevy/sblock.html. Mortec says the same things. This is a 1967 only block that was SJ for 327 and 302 but '67 Camaros with 350s got the same 4" bore block with the saddles machined for a LJ crankshaft (http://www.camaros.net/forums/showthread.php?t=143669).

There were no factory built cars with 4-bolt mains until 1969. No Corvettes, Z28s, or SS350 Camaros. If there were some blocks cast in '68, I believe they were for '69 model year vehicles.

http://www.ncrs.org/forums/archive/i...p/t-85289.html
I had not keyed in that there were no 4 bolts in '68 until recently. I had always assumed that the Z28s and SS350s in '68 got them. I knew that the '68 Corvettes did not. So that makes it even less likely that a 327 ever had 4-bolt mains because in '69 the only application for 327 was Camaros and B-bodies-and it was a more base engine as both had 350 performance engines available. By 1970 the 327 was gone and the 307 and 350 was it.
So '68 Z/28s and SS350 Camaros have 2-bolt mains.
http://www.holisticpage.com/camaro/camaros/302.htm

http://www.chevy-camaro.com/faq/chev...o-faq-Z28.shtm

http://www.camaros.net/forums/showthread.php?t=164584

http://www.hotrodders.com/forum/buil...evy-57753.html

Some LJ blocks cross over boundaries. For example, the 3956618 blocks were a 2-bolt for 68-69 327, a 4 bolt for 69 Z28, and 2 or 4 for 69 350. the famous 3970010 (and 3932386) is similar, but has no 68 applications. The raw casting had enough meat in the right places to machine it with either style cap.

No SJ block ever had 4-bolt mains. No documented 4-bolt LJ 327s were built. I could see a possibility in '69 with 0010 or 2386 block, but with all my searching I have yet to find anybody that can prove they have a legit one. And as we know, you could never prove it in a truck even if it did happen because the VIN derivative is not on the engine pad.

There are rumors of Massey-Ferguson combines with 327 4-bolts. The is no evidence this ever happed. Just another part of the legend.

http://www.chevytalk.org/fusionbb/sh...hp?tid/157044/


http://www.thecombineforum.com/forum...et-engine.html

There were industrial and marine engines from Chevy (and Ford and Chrysler). MF Combines did have Chevy 327s, but they were 2 bolt mains. MF combines did get 4-bolt SB engines, but they were 350s. I still maintain 2 things:
1-there is no such thing as a factory 327 with 4-bolt mains. Ever.
2-there were no small blocks with 4-bolt mains before the 1969 model year.

If there is any proof otherwise, I would love to see it.

The thing with all that is it is 100% car guy oriented. Not a single word on trucks, other than their motors can't be verified due to no partial VIN stamped in the block. Well, that's a Camaro guy talking, and he would need that number to have any idea of what he is talking about. A truck guy who knows these things inside and out up, down, and all around is your book. No mention of the 327s used in 40-60 series trucks or pickups.

[special-K]

Originally Posted by ericfallon

Problem now is you can buy a china doll steel casted crank..
Have never used one but they are said to not be cast iron.

Ah yes, those masters of metallurgy. Well, I guess now we'll have to start saying steel, cast, or China doll steel cast

I think I'll keep that one out of my vocabulary. I don't expect to use it.

[67 chevelle]

67 and earlier small journal cranks were all forged , after opening probably 50 68 plus sbc's 4 bolt and 2 bolt , ive yet to see a forged crank in the newer sbc's

[MARKDTN]

Originally Posted by special-K

The thing with all that is it is 100% car guy oriented. Not a single word on trucks, other than their motors can't be verified due to no partial VIN stamped in the block. Well, that's a Camaro guy talking, and he would need that number to have any idea of what he is talking about. A truck guy who knows these things inside and out up, down, and all around is your book. No mention of the 327s used in 40-60 series trucks or pickups.

I don't completely disagree with your comment. But I did discuss blocks which are car/truck/industrial. I cannot speak to C40 and larger (but I think 68 was the last year for a 327 there as well). The simple facts as far as I can see:
1) 67 and back 327s are all small journal and thus cannot be 4-bolt main.
2) 68 and up 327s are all large journal-however there are no 4-bolt blocks in 68. The 4-bolt block was introduced in 69. Mortec and others do not list a 4-bolt block in 68.
3) 68 is the last year for a 327 in a C10-30 so there are no 4-bolt mains in them since the block didn't exist yet.
4) as far as I can tell the only 327s in 69 went into Camaros and B-bodies, not into any trucks. C10-30 Trucks got 350s in 69.
5) Of course a 327 4-bolt can be made, but the factory never did.

[67 chevelle]

Opps , there was one I had ,, only one , it was a 70 lt1 motor that was in a 68 camaro I bought , ran like crap when I got it , heads were shot , exhaust seats sunk , I put 200 cc dart sportsman heads , and a 280 h cam in it , ran 12 flat with very little traction .

[harpo231]

Originally Posted by ericfallon

Problem now is you can buy a china doll steel casted crank..
Have never used one but they are said to not be cast iron.

cast steel = less than 0.5 % carbon

cast iron = more than 2% carbon

[special-K]

Originally Posted by MARKDTN

I don't completely disagree with your comment. But I did discuss blocks which are car/truck/industrial. I cannot speak to C40 and larger (but I think 68 was the last year for a 327 there as well). The simple facts as far as I can see...

Yeah, I'm not arguing anything. I can't argue on the 4-bolt thing because I truly can't recall at this point. It was an absolutely original '68 C/20 327 when I rebuilt it. It was certainly a forged crank in there. I was saying those articles never mentioned larger trucks is all. They did mention industrial, but the two aren't the same. So, are the block casting numbers for 302-327-350 that list as 2-bolt & 4-bolt mean 2-bolt at first, then came the 4-bolt in the same casting? I'm talking about 3932386 (68-74) and 3956618 (68-79).

[jeffahart]

Just update the history to show: 1970 K20 350 with a two bolt main. It threw a rod through the side of the block at under 80k. So what, plentiful and cheap to replace, even when I did this particular truck way back in the 80s.

My expectation on any engine in these old vehicles is... the lowest common denominator. Anything else is a plus.

OP should not pull his pack and upgrade anything if it's running fine. I can't figure for the life of me why you care what crank it has, especially if a crate is being considered. Unless what crank you have is a deciding factor to keep your engine and work it.

I think he should look at the crank and let us know.

This thread has been an interesting read; a lot of fun engine trivia stuff.

For the OP. I tend to work with what I got. If I want something specific in an engine, I go buy it. Rule of thumb... assume nothing!

You've read the prose here. What crank do you have? Exactly!

[MARKDTN]

Originally Posted by special-K

Yeah, I'm not arguing anything. I can't argue on the 4-bolt thing because I truly can't recall at this point. It was an absolutely original '68 C/20 327 when I rebuilt it. It was certainly a forged crank in there. I was saying those articles never mentioned larger trucks is all. They did mention industrial, but the two aren't the same. So, are the block casting numbers for 302-327-350 that list as 2-bolt & 4-bolt mean 2-bolt at first, then came the 4-bolt in the same casting? I'm talking about 3932386 (68-74) and 3956618 (68-79).

Yes, there are no 4-bolts in 1968. Look at Mortec
http://www.mortec.com/castnum.htm

and you will see for the 2 you mentioned 1968 is listed as 2-bolt and later applications are 2 or 4. There is enough meat to machine those (and 3970010) for either 2 or 4 bolt mains.

As far as cranks, they are all over the place. Seems like early small journal 327s got a lot of forged cranks. Large journal cars and C10 seems to be mostly cast in my experience. The bigger trucks are where the forged 327 cranks came from. This is much less documented than the 2 or 4 bolt mains.