Oil Pan Gasket

[1968CHEVYC10]

I recently discovered that my rear main seal is leaking pretty bad and possibly my timing cover. I'm guessing it's an early 70's model 350, not sure, the truck is a '68 so the motor's not stock, one've these days I'll pull the valve covers and find out. Anyway I never really done any engine work so I'm not really sure how to go about doing this, So any help would be awesome, Thanks Yall!

[1968SWBBigBlock]

To learn what engine you really have you have 3 places to look
Passenger side front of the motor right below the mating surface of the head to the block
You will find a 1.5" x 3" long pad that contains alpha numeric codes
Post that information and we have a start
On the back of the block - passenger side you will find an numeric code(this is your casting code) - on the opposite bank you will find another alpha numeric code(this is your date code) Post this information and we can confirm what the block is

[tim21391]

felpro makes a one piece gasket thats about 40 or 50 bucks and it works real nice

[cdowns]

a factory service manual is a great investment ,shows step by step the proper way to do a job such as this and how to inspect the internal parts for wear to avoid replacing unneed parts and how to reassemble correctly

[junkyardjohn]

Originally Posted by tim21391

felpro makes a one piece gasket thats about 40 or 50 bucks and it works real nice

WHEN THOSE SMALL BLOCK 1 PIECE PAN GASKETS CAME OUT A FEW YEARS BACK, I TRIED ONE & HAVEN'T USED ANY OTHER KIND SINCE. THEY ARE FANTASTIC. THE LAST 1 I BOUGHT WAS ABOUT A YEAR AGO (I THINK AT AUTO-ZONE OR CAR QUEST O-REILLYS. I'M NOT SURE BUT IT WAS ONE OF THOSE CHAIN PARTS STORES) & WAS UNDER $25. THEY ARE GREAT. JOHN

[rsavage]

The block casting number is on the driver's side rear just behind the back of the head. That will tell you what block you have - 307, 350 etc. and a range of years & applications it was used in.

[GASoline71]

The pad on the front of the passenger side cylinder head will have the engine suffix code. Then you can figure out what year, c.i.d., HP rating, and what appliction the engine is. If you get the one piece Fel-pro gasket (which are great), you need to make sure you get the proper one that fits the timing cover to pan seal. There are 2 sizes... thick and thin.

Gary

[oldblue1968chevy]

i got my motor on a stand and have a 2 piece gasket, should i swap to 1 piece or just leave it alone..

edit,its all new stuff

[tim21391]

Originally Posted by oldblue1968chevy

i got my motor on a stand and have a 2 piece gasket, should i swap to 1 piece or just leave it alone..

edit,its all new stuff

im running a 2 piece gasket on my 347 stroker.. and it'll be fine.. i just like the one piece because i heard you dont any adhesive or what not and i also heard if you take your oil pan off in future u can still use that same gasket

[leddzepp]

Originally Posted by oldblue1968chevy

i got my motor on a stand and have a 2 piece gasket, should i swap to 1 piece or just leave it alone..

edit,its all new stuff

What is your 2 piece composed of? If it is cork, I would replace it with a 1 piece. If it is rubber, I would leave it alone. I like the 1 piece because it is easy to install, but the best thing is that it is made of rubber and will not leak.

[junkyardjohn]

Originally Posted by oldblue1968chevy

i got my motor on a stand and have a 2 piece gasket, should i swap to 1 piece or just leave it alone..

edit,its all new stuff

BY ALL MEANS... CHANGE IT NOW WHILE IT'S NICE & EASY TO GET TO. BUT THATS JUST ME... I'M A LAZY SH!T AT HEART, & IF YOU'VE EVER LAIN ON YOUR BACK, UNDER ONE OF THESE OLD TRUCKS & WRESTLED THE OIL PAN OFF... WELL I'D RATHER BE BEAT WITH A STICK. AWFULLY CHEAP INSURANCE. AFTER USING THEM... I'M SURPRIZED THEY EVEN MAKE THE OLD TWO PIECE CORK BUGGERS. THEY ARE THAT GOOD. I ALWAYS BELIEVED IN FEL-PRO GASKETS & I'VE GOT TO BE THIER #1 FAN. THIS IS 2010 & THATS 1952 TECHNOLOGY AT IT'S FINEST. JOHN

[GASoline71]

Your choice... But the 1 piece is superior IMO.

Just make sure to get the correct gasket depending on your timing chain cover to pan seal.

Gary

[1968CHEVYC10]

Ok just went and looked at the numbers, they were a little different than described, that or I got it backwards. I found two numbers, one which was on the back of the motor on the lip that attaches to the transmission on the driver's side, 3970010. the other on the passenger side of the block on the lip, G28(?) I couldn't make out the last figure, and unfortunately that's the number I need to know. I did a little research, the first number means it's a '69-'79 350, the second from what I could get means July 28, I'll have to check again to see if I can make out the last number.

[1968CHEVYC10]

OK just went and looked again, took a few pics, let me know what yall think.

[1968SWBBigBlock]

Great - that is your date code =- go to the other side of the block - same area but in a larger font will be you casting code.
Sometimes we need to put together a couple of items to make sure we know for sure what we have.
G = July
28 should be the 28th day of the month
1 = should be a 71 motor
The other option would be July 2 1981 - the blue paint makes me question the date - it would be correct for a 81 motor - but the way the casting number is laid out it looks like the 28 belongs together

[1968CHEVYC10]

Originally Posted by 1968SWBBigBlock

Great - that is your date code =- go to the other side of the block - same area but in a larger font will be you casting code.
Sometimes we need to put together a couple of items to make sure we know for sure what we have.
G = July
28 should be the 28th day of the month
1 = should be a 71 motor
The other option would be July 2 1981 - the blue paint makes me question the date - it would be correct for a 81 motor - but the way the casting number is laid out it looks like the 28 belongs together

according to this site http://www.nastyz28.com/sbchevy/sblock.php the day of the month is a 2 digit number, so if it was the first of the month it would be 01 instead of 1, and the casting code puts it as a 69-79.

[GASoline71]

What is the number stamped on the pad in front of the passenger side cylinder head?

Gary

[oldblue1968chevy]

^yup that tells it all...

[GASoline71]

If you get the number off of the area in front of the passenger side head, you will get the engine suffix code. The last 3 digits in that number.

The suffix code will tell you the exact year, c.i.d., HP rating, and how many barrels the carb was from factory.

Gary

[1968CHEVYC10]

Originally Posted by GASoline71

If you get the number off of the area in front of the passenger side head, you will get the engine suffix code. The last 3 digits in that number.

The suffix code will tell you the exact year, c.i.d., HP rating, and how many barrels the carb was from factory.

Gary

are you saying it's on the front of the engine? I looked there earlier and couldn't find anything. Does anyone have a picture of where it is and what it looks like? thanks!

[1968CHEVYC10]

the blue paint makes me question the date - it would be correct for a 81 motor

I forgot to mention, there is orange paint under the blue paint, I'm not totally sure what would be correct from the factory but I think the orange paint would be the right paint if it was a '71.

[1968CHEVYC10]

I've been doing a little research to see if I can do this whole thing without lifting the motor a few inches but it look like I'm gonna have to. I'm not real sure where to hook the chain for lifting it. I don't have an engine hoist but I have a tractor with a front end loader which oughta work pretty good. Also is there any special links or hooks I'll need?

[btullis99]

when i built the motor for my truck, i used the old style cork junk and had a nice fat oil leak, luckily it was on a test stand and was easily changed to a felpro one piece gasket. autozone had it in stock, there are only two kinds, the difference has to do with the thickness of the gasket at the front where it meets the timing cover. if its a pre 1980, i believe its the thicker one, and if its a post 1980 they changed it too the thinner one. this is the year of change on which side the dipstick is on too. i do remember at first i thought i had the wrong one because it was looking too thick where it met the timing cover, but after starting the bolts and little shoving, it fit like a charm and has never leaked again. the gasket also has little steel hoops around where the bolts go through it so you can't over tighten the pan bolts too easily.

[GASoline71]

Originally Posted by 1968CHEVYC10

are you saying it's on the front of the engine? I looked there earlier and couldn't find anything. Does anyone have a picture of where it is and what it looks like? thanks!

The number I'm talking about will be on the flat spot on the block just in front of the passenger cylinder head, and just behind the upper water pump bolt. You can't read mine because of the 5 coats of Chevy Orange paint... LOL

My suffix code is TDJ

Gary

[1968CHEVYC10]

Thanks for your help Gary, I think I've got it. My suffix code is TYZ which translates: year: 1975, cid: 350, hp: 165, carb: 4bbl. So does this mean the last number on my Casting date is supposed to be a 5? sure doesn't look like it, were these numbers ever known to come out crooked from the factory?