[Rick0087]

So I have a 283 crank it reads GM-11 3849847 cast number and have searched forums up and down and can't really figure it out so forums say its forged some say cast. the center line points to cast being a thin line but when you hit it with a hammer it rings like a bell I have read on another forum that sometimes cast and forged will make different sounds IDK. Any ideas out there is there anyway for it to be forged with the thin center cast line? is there any other id number that might help I know there's the date code on it but didn't think that would help much I know by the cast number its a 1963-67 crank just at a total loss here any help would be appreciated. thanks guys!

[cobalt327]

Originally Posted by Rick0087

So I have a 283 crank it reads GM-11 3849847 cast number and have searched forums up and down and can't really figure it out so forums say its forged some say cast. the center line points to cast being a thin line but when you hit it with a hammer it rings like a bell I have read on another forum that sometimes cast and forged will make different sounds IDK. Any ideas out there is there anyway for it to be forged with the thin center cast line? is there any other id number that might help I know there's the date code on it but didn't think that would help much I know by the cast number its a 1963-67 crank just at a total loss here any help would be appreciated. thanks guys!

The sound isn't indicative of cast or forged. The DO make a different sound when hit, but unless you have both cast and forged side by side, the comparison really cannot be made difinatively IMO.

Thin line should be cast. But a 3" stroke factory SBC crank is going to be forged.

[geezer69]

i had a steel crank and block, 283. i couldnt tell from just lookin. the guy that gave it to me showed me the ping thing. i couldnt really do that either. even side by side with a cast crank. hahaha. he also said he can find a crack in a crank by that ping test. is he b s'n me or do you guys know anything about that. i dont know much about engines. just piddle with em.

[cobalt327]

Originally Posted by geezer69

i had a steel crank and block, 283. i couldnt tell from just lookin. the guy that gave it to me showed me the ping thing. i couldnt really do that either. even side by side with a cast crank. hahaha. he also said he can find a crack in a crank by that ping test. is he b s'n me or do you guys know anything about that. i dont know much about engines. just piddle with em.

Some cracks at the earliest stages are barely visible even w/penetrant or magnaflux, but the different sound w/a cracked crank crack is legit. The sound is very different w/a significantly cracked crank and to someone who deals w/them on a regular basis its a no brainer. Not so much to someone like us who don't handle cranks a hundred times a day unless the crack is bad or you have a good one to compare it to.

[AutoGear]

My grandad was an old school welder; he was born in 1918 and learned things like hammer welding, cast iron repair and gas aluminum welding and used them every single day. He had 2 big anvils in the shop; a cast one and a forged one. Yes there is a difference, no its not easy to tell and I have a feeling the larger the object, the easier it is to hear the difference.

There was a cast 262 (yeah I said it 262) crank; I think its actually 3.10" stroke, but its a large journal crank if Im not mistaken. I heard of guys using them in a 283 block (why not just blueprint a 307 I dunno).

Now; chevelles.com list that as a 1964 crank and is labeled as cast or forged???
http://www.chevelles.com/ref/64f.html

interesting... Over the counter service replacement?

[cobalt327]

Yeah, interesting. I'm not convinced they would use a cast small journal crank, at least not in regular production. FWIW, I have never seen one, but who knows what could have been used as service replacements.

[AutoGear]

To the OP:

If you are in dire need of a 283 crank and its free; or you're building a numbers matching 283 from 1964, use it. If you just need a crank for a 283, find an earlier one that is confirmed as steel. I've been given 283 parts and if its a GOOD crank I could see paying $50-75 for a non-corvette piece.

Nothing wrong with a 283; get a rebuild kit from Northern, some moly rings, a 260H cam, a small aluminum intake manifold with a 600cfm carb and you've got a nice piece

[vinniekq2]

Ive never seen a 283 cast crank.if it exists,what did it come in?

[cobalt327]

That's what we're wondering, too. Like Auto Gear said, possibly a service replacement part? There's at least a fair chance it's forged w/an odd parting line.

[Rick0087]

So I am going to take it to a machinist that specializes in cranks today and see what he has to say. ill try to get some pics up of it here soon and let you all know the results. and for its purpose I am building a 302 yaya i know lol I did happen to stumble upon an original 302 DZ engine with original crank waiting to see if its for sale was left a my machinist shop for over 2yrs so i might have a chance at getting it ya y1a

[Rick0087]

so the machinist has verified it is a cast crank so it looks like i am buying one from him. grrrr heres a question for you guys that he mentioned to me about making a 302 is the pistons height is like 1.8 and a 350 piston height is 1.5 so couldn't I just use a 350 piston 5.7 on a 6" rod to make up the difference? so the piston height would be back up to stock 1.8???

[1971BB427]

Originally Posted by AutoGear

To the OP:

If you are in dire need of a 283 crank and its free; or you're building a numbers matching 283 from 1964, use it. If you just need a crank for a 283, find an earlier one that is confirmed as steel. I've been given 283 parts and if its a GOOD crank I could see paying $50-75 for a non-corvette piece.

Nothing wrong with a 283; get a rebuild kit from Northern, some moly rings, a 260H cam, a small aluminum intake manifold with a 600cfm carb and you've got a nice piece

Aren't they both steel? Isn't the difference either forged steel, or cast steel, not forged steel or cast iron?

[vinniekq2]

first,just buy 302 pistons,use 283 rods and a small journal 327 block.

Problems: 283 uses a small pressed on ,one piece balancer,many prefer to use the bigger 2 piece balancer. If you have a 350 block,then buy a large journal 302 crank. then its worth upgrading the rods.large journal rods are more common so price is fair.
If you have a 283 block then consider building a 292 (060 over 283) you only lose 13 inches.
Depending on how much horse power you want? its easy to get too much cylinder head on that little engine. A small runner 2.02 head will make lots of power. I wouldnt build much more than 425 horse power for a normally aspirated 5 liter

[cobalt327]

Originally Posted by Rick0087

so the machinist has verified it is a cast crank so it looks like i am buying one from him. grrrr heres a question for you guys that he mentioned to me about making a 302 is the pistons height is like 1.8 and a 350 piston height is 1.5 so couldn't I just use a 350 piston 5.7 on a 6" rod to make up the difference? so the piston height would be back up to stock 1.8???

The 350 piston has a compression height (CH) of 1.56" stock or 1.54" if they're "rebuilder" pistons.

So the stack would look like:

deck height (9.025" to 9.00") minus 1/2 stroke (1.5") minus rod (6") = 1.525" CH, or 1.50" CH if zero deck (9.00") block.


Using a rebuilder piston this puts the top of the piston out of the cylinder at TDC by 0.015" if the block is uncut, or 0.035" using stock CH piston.

Using a zero deck block, the 1.54" piston is 0.040" out; 0.060" out if using stock CH pistons.

[Rick0087]

Thank you so much cobalt327 Now it makes sense to me! I would buy 302 pistons if they weren't 500+ dollars a set with out rings! also on that note its hard to find a 302 dish piston for running forced induction. my goal is 8.5-9CR The other huge problem with 302 piston is most of them are around 11-1CR and while I love a nasty N/A V-8 I can't see using race gas to just play around cause that's what I will mostly be doing don't get me wrong I will be going to the drag strip and autocross.