# above water pump is 3161-5a

 

im trying to find the size and year of my motor numbers above water pump are 3161-5a

 

Welcome to CO.
What you have is a 80-84 Olds 307

 

Welcome, post some pictures of your car when you get a chance.

 

was told by last owner it was a 350 its in a 82 cutlass supreme brougham 4 dr when I did first tune up 307 plugs didn't match up,i replaced oil pan gasket it was a 350 gasket. I am now putting a crank kit and timing set in.just wanna be sure im ordering rite parts

 

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i would say someone put a 350 in it at one time

 

vin says its a 4.3 260. # above water pump is 3161-5a.the crankshaft # 556607 (replacing this shaft). # under #1plug is hard to make out could 56x721085 its the 56 im not sure about could be 00 or 66

 

hello im putting a crank kit and timing set in my 82 cutlass . vin says its a 260 but # above water pump (3161-5A) shows it to be 81-84 307.when I first got the car I replaced the plugs. 307 plugs didn't match what was in it which were for a 350, the 307 plug was longer so I used what was in it. I just wanna be sure im ordering rite crank and timing set

 

I read your other post...I have one book that also lists that block number as a 80-84 307, just one more confirmation. Can't narrow that down any more than that.

Welcome and good luck.

 

Does it say

"3161 GM 5.0L"

above the timing case??

 

no just the 3161-5A above timing casing. Ive heard that most parts will interchange between any small block olds is this true for the crankshaft

 

All Olds motors from the 260 to the 455 use the same oil pan gasket.

I don't know what you mean by "307 plugs didn't match up". All Olds factory heads accept the same size plugs. If the numbers were different, they were likely changed by a previous owner.

In any case, the casting number pretty clearly tells you what block you have, with no uncertainty whatsoever.

 

It's either a 3.8L Buick or a 307 Olds in there, assuming it's orginal

 

As noted, the 3161-5A is a 307. There's no question of that.

You need to look at the VIN derivative again. The first character is the car line. "5" was not used to designate a GM car line when the 307 was in production. That's probably a "6", meaning Cadillac. 307s were used in Fleetwoods and Eldorados.

The second character is the model year. In the 1980s GM used letters, not numbers, to designate model year. What you think is a "6" is more likely a "G" for the 1986 model year. Your 307 is likely a roller cam motor with 7A heads.

The third character, "X", designates the Fairfax, KS assembly plant.

Your VIN derivative is most likely 6GX721085.

 

307 plugs were longer than what was in it. that must have been last owners mistake. thanks for the info

 

just trying to post in the rite fourm

 

well now that I have found all of my posts where I was told they don't belong, I have 5a heads and 86 doesn't fall between 80 and 84 as per the 3161-5a.

 

Let's start with a confirmation of what the VIN derivative really is, which will avoid guessing. Also, since that engine was obviously installed in that car by a prior owner, it's also possible that heads were changed, along with who knows what else. This isn't a factory installation, so all bets are off. The VIN derivative stamp is THE authority on the year of the block. Don't believe everything you read in the Olds FAQ, as there are a multitude of errors.

Also be aware that Cadillac installations of the 307 didn't always match Olds configurations. For example, in the second half of the 1980s, many Fleetwoods actually used VIN 9 motors, not VIN Y motors. Unfortunately without the VIN of the car that motor was born in, you'll never know.

As for finding your moved threads, simply click on the MOVED link in the other subforums and you are taken directly here.

 

I believe your right on the vin der for sure on the G and as near as I can tell it is a 6 unless its possibly 5. im going to order crankshaft as listed for the 82 cutlass 307 at auto zone and go from there. thanks for the helpful info.

 

Why wouldn't you get one for an 86 Caddy Fleetwood with a 307, which is apparently what this short block came out of?

OK, I just checked and as I suspected, the crank kit part number is the same for both the 82 Olds and 86 Caddy 307 motors, so you're good to go.

 

cross referencing part #s was included in that plan. thanks again