I have just purchased a new 350 block for rebuild. It has casting number 14093638.

How do I know if it has the large or the small journal bearings?

I know, I know...."how could anyone not know that!"

Thank in advance!

Cliff

 

I'd forget the "large" and "small" terminology and measure it. Use either a telescoping bore gage or a dial bore gage. You'll need those measurements (and those of the crank journals) to get the right size bearings anyway.

There can be any number of interpretations of the words large or small. Numbers can only mean one thing.
Good luck with your rebuild and have fun!
S-D

You may also be able to find some additional info at the Mortec site.

 

It's a 350.

It is what is commonly referred to as "large journal", like every other 350.

Small journals were discontinued in the late 60s and never were used in 350s.

The only other journal size is in 400s, which you don't have because yours is a 350.

 

RB-
I dug up a an article in the August 2003 issue of Chevy High Performance article "Bearing Up" (pages 82-89) and had a question.
This link is only to the table of contents for the august 2003 issue. I couldn't find that actual aritcle on their site.
http://www.chevyhiperformance.com/to..._toc/index.htm

I see, that on page 88 of the article (which seems to cover 350s and 400s), there is a yellow column called "Block and Crank specs" that makes mention of Small, Medium and Large main housing bores.

"Small = 2.4906 - 2.4916
Medium = 2.6406 - 2.6416
Large = 2.8406 - 2.8416"

I helped a friend measure clearances on a 400 and we found the 400 uses 2.8406-2.8416 mains (block main bore).

So, the "large 350" is 2.6406 - 2.6416 and the "small journal" is 2.4906 - 2.4916 (was this a 283 or something?).

I see that there are only "small" and "large" housing bore values listed for rods.
small rod journals = 2.00
large rod journals = 2.10

I have never been clear on this and that is why I generally prefer to use the numbers when communicating engine specs.

Any input you may have is appreciated-
Thanks,
S-D

 

My memory must be failing. I always though the small journals wer 2.30, mediums were 2.45, and large SBC journals wer2.65" (nominal sizes).

 

You're memory is fine. My post mentions block main bore (w/out bearings) sizes. Your post mentions crank journal sizes.


S-D

 

Walk into a machine shop and call a 350 "medium journal" and tell them you read that in a magazine, and they might give you a discouint for the humor after they stop laughing at you for being inexperienced. Then again, they might just look at you like you have 3 heads, and never believe another word that comes out of your mouth, having irrevocably marked you down as a newbie.

The commonly used terms among people who actually build motors for the last 35 years have been "small journal" for the old 265, 283 and 327, from 55 to 67; "large journal" for the 350, 305, 267, 262.5, 307, 302, & 68-up 327; and "400 journal" for the 400.

One magazine article published 35 years after the fact does not single-handedly create a naming convention.

 

Yup, I know what you're saying. The scary part is that the "S - M - L" designation is even starting to show up in some parts catalogs. Maybe we can thank the Chinese (Scat and Eagle) for that. Then again, we used to call them "blocks", while the newer buzz is "case". Or maybe it's a regional thing, like "hoagie - grinder - submarine" sandwiches. I'll have to admit, I'm not that experienced. I only cracked into my first one in about 1974 (Chevy, that is). I'm just trying to atay current with what all the kids are using these days.

You down with that, Dawg?

 

Ouch! Well, that would open up a whole new class of people that laugh at me!

I appreciate you taking a moment to clarify what engines fall into the small and large journal classification.

So, is this correct:
small journal = 2.29XX inches
large journal = 2.44XX inches
400 journal = 2.64XX inches

Thanks,
S-D

If anyone needs me, I'll be out in my garage rooting around looking for that confounded medium journal engine block I've got hiding out there..............
edit: I meant to say medium journal "case". I got that one out of the July 03 issue of Super Chevy.

 

Great information! Ok, so when I'm ordering from Jeg's, I'm looking at the large journals.

Thanks for all the great info!!

Cliff

 

Yeah, I have been seeing that more and more of late. It isn't just CHP, but other magazines, books, and catalogs.

Is it a "pulley" or a "sheave"?

With the proliferation of SBC-IIIs, I wonder how long it will be before the newer camshafts are called "hollow" and the older ones are called "solid". That should add a bunch more confusion to ordering from the lowest-priced suppliers.

"Let's see... Would that be a solid/solid, a solid/hydraulic/flat, a solid/solid/roller, solid/roller/hyrdaulic, or a hollow/solid for you today? And would you like any sauce with that?"

And just in "case" you weren't laughing enough already, just picture what's inherently wrong with a 40-ish-something white guy trying to be "hip"? Sounds like a couple Pepsi commercials I've seen lately...