Crank castin numbers

[whitesswj]

Where are the number located at on a sbc 350 crank.
I've found the following w/o rotation the crank:

both of these on the same counterbalance
L223 (i'm gathering Dec, 23 19? 3)
93244

on a more front balance.
5 98
GM12

and thats it
found the clock pointing at 4 from the 2dots

what can you guys tell me - i've looked all over the net and can't find any info on it. thanks sswj

[canadianchevy72]

The number is on the counterweight it is 5 numbers I believe. The second number you posted I think is it check it at www.mortec.com

[MJN]

the number should be eight digits long and on an unmachined part of the crank below a counterweight for example 3932442.
L223= December 22 1973 or 1983

[whitesswj]

found the castin number:
3932442 which is: 3932442..267,305,350..cast...medium journal...3.48" stroke

what does this stuff mean?

[1972C10]

Its just a plain Jane Cast Crank For A Large Journal
267/305/350 Mortec refers to large journal as medium because of the Sb 400 mains Its the largest Journal Small Block

[whitesswj]

yea, but what's a journal and what is 3.48 stroke? and to those that know much more than i, what is a compression ration. i.ei my head is 3998991....72-73...307/350......75cc chambers
what is this? and the compression when the pistion chambers are bored to .60? BTW the block is 14010207...350...80-85...4 bolt main.

[1972C10]

A journal is the part that the crank rides on the block on .. Or the part that the rod rides on on the crank

Compression is hard to say if you are using stock type dish pistons you will get somewhere around 8-8.5-1

Those heads Might Not have hardened Seats Be sure to get them checked


3.48 stroke is the amount of travel the crank pushes the piston up .


Kinda hard to explain the simple questions sometimes but i hope i helped.

[whitesswj]

but what does compression mean?
seats?

[1972C10]

Compression is the amount of pressure a cylinder has before it fires Compression ratio

Seats are seats of the valve .. Valve seats.


I suggest you find a good engine shop to take your stuff too.

Do what i did Find a good engine shop that doesnt mind people hanging around a little

Then go up there From time to time see what you cant learn.

I might have been fortunate to have a engine builder that let me hang out but i also had like 9 engines built there.

[lukecp]

Compression ratio is the ratio of the initial volume of air in the cylinder and combustion chamber to the volume of air in the cylinder and combustion chamber when the piston is at top dead center. A 8.5:1 comprssion ratio would mean if there was 8.5 cublc inches of air in the cylinder it would be compressed to 1 cubic inch of air at about the time the spark plug ignites the mixture and the enigne fires.

Those 76cc open chamber heads will give you a lower compression ratio, proably about 8:1-8.5:1 as stated above. You will be able to run 87 octane fuel no problem, but low compression is not good for power. I've heard that for every 1 point increase on compression there is a 4% increase in engine power. However, with the higher compression the tempertaures in the cylinders increase and you have to run higher octane (more expensive) fuel to keep the fuel mixture from igniting before it is supposed to, which can cause lots of damage.

The hardened seats refered to are the pads in the head that the exhaust valves close on. Older cylinder heads will have just a cast iron seat, and are designed for leaded fuel. Newer heads will have a hardened seat made of a different metal installed there. The lead in the fuel used to provide protection for the closing valve, but once it was eliminated the valve seats would wear out quickly and hardened metal seats had to be installed so they would last many miles w/o leaded gasoline.

[1972C10]

I guess My Explanations Work Better For Somone Who has A Decent Knowledge Of The Inside Of An Engine ..


Good job. yellow.

[whitesswj]

the engine i bought was a rebuilt Fliteline (Fort Smith, AR) engine 350 bore at 060 mains 020 rods 020. And i should definatly take that advice when i get to memphis and get to know some good ole mechanics. I mean i know enough to get by but that's it - get by. Thanks.

[1972C10]

Im Not Too big Of A Fan Of A Crank Being Cut Past 0.10 0.10 But if your not doing awhole of of stuff 20 will work Friend of mine runs one but he doenst treat his the way i treat mine . .

[whitesswj]

what was stock? and what dose that number mean, i can only gather that the engine now has a bigger rods or put it in a young persons terms :smile:

[1972C10]

Stock journal sizes are 2.45 and 2.10

0.20 0.20 means that they have been ground down 20 thousandths of an inch

wich means there is less crank there.

The more the crank is cut the thicker the bearings are.

IMO 0.20 0.20 are good for stock engines and grandpas 305

For any kind of hot rodding i wont run nothing but STD or 0.10

[whitesswj]

makes good since