Curious of 401 engine year

There's been talk in a recent thread about non-matching numbers cars. Well it turns out I have one of those non-matching numbers cars. The sad part is that after 22+ years of ownership I just assumed my car was unmolested.…I know…that's what I get for assuming.

Regardless, I don't know that I would've taken a different route on my build if I had found this out sooner. I'm a bit too deep into my project now anyway.

Here are pics of the numbers stamped into the leading edge of my block. The passenger side numbers look very neat, straight & totally different than the numbers I've seen you guys post. The numbers on the driver side (which are suppose to match the vin but don't in my case) look more like all the block numbers I see guys post on this forum.

I am curious if anyone can help me figure out what year car this engine came from? Or where can I go for more info? Any info at all would be appreciated.

David

Engine production code = 4I

4 = 401 V8

I = 1962

7006 = some sort of date or build sequence code

Serial number (hard to read the last few digits) = 6I20x1517

6 = Invicta

I = 1962

2 = South Gate, California

0x1517 = sequential number, range for South Gate was 001001 to 020852 for fullsize cars

Wow! You guys are amazing!

Sean1997, thx you very much for helping me with this piece of the puzzle.

Kind of a jaw dropper for me. Feels like someone just told me my kids are not related lol

Still love it, thx again

David

Here's a link to TeamBuick.com that shows the 59 - 62 numbering system. The nice thing is that all 401's starting in 1959 were rated at 325 hp, the same as in 1965

http://www.teambuick.com/reference/ident_engine_59-62.php

The next thing that I would do if I were you would be to check the casting date code on your intake manifold, and the carb #. It could be that only the short block is from a '61. Google "Russ Martin Buick nailhead" on the internet and read his tech article* and find out what he says about differences in nailheads from year to year. That will help you when replacing water pumps, starter motors, and other things that took place throughout production. If this '61 engine is connected to the stock '65 transmission, then the '61 short block either has a 64 or later crank in it, or the '65 flex plate has been machined to fit the '63 crank, or an adapter has been added to the end of the '63 crank so the '65 flex plate can be bolted on. Now that you know your kids aren't your own, you'll be better able to provide for them knowing their previous heritage.

*http://nailheadbuick.com/how-to-know-what-sizeyear-nailhead-you-are-looking-at

One of many articles that will help you know what you're looking at.

Don't feel bad about the news

IMO it really doesn't matter

You have a great car with an authentic engine

Numbers matching has no relevance if you're going to drive and enjoy the car

Still a fantastic ride

My 65's original engine blew, and was replaced with a 401 nailhead rebuilt from a previous year.

Knowing this, I still bought the car with no regrets

I enjoy my car as a wonderful automobile to drive; that's what they were made for.

Enjoy your car in good health!

OK RRD: The engine you have originally came with an open Dynaflow. If your Riviera is a 64 or 65 you can check to make sure the swap was done somewhat correctly. Ed is an expert at what needs to be done in this situation. And again, matching numbers in my opinion is juvenile mythology. Why people came up with this ridiculous nonsense is a subject for shrinks to deal with. Mitch

This is a perfect example why matching numbers adds value.

As the circumstances dictate, Dave is left wondering whether the installation of a `62 vintage motor was done properly over 22 years ago when his Riv was basically an inexpensive used car. I highly doubt that it was.

Assuming a `62 engine was installed as an economical repair, the original flex plate was most likely butchered to clear the raised area of the `62 crank hub which weakens the flex plate. In addition, the nose of the `65 converter is left unsupported by the too large recess in the hub of the `62 crank which further stresses the flexplate. These issues will eventually result in a cracked flex plate.

Aside from potentially needing to troubleshoot the noise coming from the lower end of the motor, the starter motor will get replaced a few times before transmission removal becomes necessary to properly inspect the flexplate due to starter drive binding/noise. A new flexplate will need to be obtained whose balance does not exactly match the original, because the Nailhead is externally balanced, and the unfortunate weekend mechanic/owner will spend the rest of his ownership and much time and money trying to cure a vibration problem which presents itself mostly at 65MPH, but not exclusively, when, in fact, the problem is an engine balance problem and not in the wheels/tires or driveline. Ask me how I know this sad scenario.....went thru it 35+ years ago as a green tech and amateur collector. Back then, info was not readily available for this type of situation. In the long run dealing with this situation was more time consuming and expensive compared to rebuilding the original engine or using the appropriate replacement.

I hope Dave finds the installation was done properly! But if I was a potential buyer looking at Dave`s car, even though for me these issues are easily rectified because I have the parts and am a mechanic by trade, I would expect the worst and build a substantial discount into my best offer, all because the original and appropriate drivetrain components are not in place. After all is said and done, time is money, whether the time is my own or someone else`s.

Dave, no offense to you or your car intended by my post...just making a point. If you need any help please feel free to contact me directly. My contact info is in The Riview. Best of luck!

Tom Mooney

"I hope Dave finds the installation was done properly! But if I was a potential buyer looking at Dave`s car, even though for me these issues are easily rectified because I have the parts and am a mechanic by trade, I would expect the worst and build a substantial discount into my best offer, all because the original and appropriate drivetrain components are not in place. After all is said and done, time is money, whether the time is my own or someone else`s.

Dave, no offense to you or your car intended by my post...just making a point. If you need any help please feel free to contact me directly. My contact info is in The Riview. Best of luck!

Tom Mooney

That's right instill fear into scenario and shake the man's confidence in a ride he's had for 22 years

Replacements done properly hold well with time. No need to scare the owner into thinking he has a lesser ride due to your projections.

Numbers matching still is a bunch of malarkey

When a spark plug wears out you replace it

when a tire tread wears you replace it

when a car is driven, and the engine blows you replace it

Big deal

"I hope Dave finds the installation was done properly! But if I was a potential buyer looking at Dave`s car, even though for me these issues are easily rectified because I have the parts and am a mechanic by trade, I would expect the worst and build a substantial discount into my best offer, all because the original and appropriate drivetrain components are not in place. After all is said and done, time is money, whether the time is my own or someone else`s.

Dave, no offense to you or your car intended by my post...just making a point. If you need any help please feel free to contact me directly. My contact info is in The Riview. Best of luck!

Tom Mooney

That's right instill fear into scenario and shake the man's confidence in a ride he's had for 22 years

Replacements done properly hold well with time. No need to scare the owner into thinking he has a lesser ride due to your projections.

Numbers matching still is a bunch of malarkey

When a spark plug wears out you replace it

when a tire tread wears you replace it

when a car is driven, and the engine blows you replace it

Big deal

Dan,

If the replacement engine was a turbo 400 application I would not have the above reservations....but it is not. My hope is, as a result of the info presented here by myself and others, that Dave doesnt go thru the frustration that I did many moons ago.

Your spark plug analogy is obvious hyperbole.

If viewing a potential purchase and I find it needs a set of tires, I would discount my offer by $500.

If I needed to address the concerns I expressed above that would be a big deal; probably a deal breaker if I had a similar potential purchase with matching numbers.

My opinion re matching numbers is not only my personal preference but is supported by what I have seen happening in the market place for decades. Dont take my word for it, review listings in Hemmings, auction descriptions, etc....there is more than enough support to recognize the link between matching numbers and value.

Dave, AGAIN, if you need any help or would like a more thorough explanation of the potential issues with your `62 motor, please feel free to call me directly. Evenings are best...best of luck!

Tom Mooney

I ran into what Tom relates in a '66 Electra that had a '62 401 installed. That said, I don't fuss too much over non original components in the old cars=it's common enough to find that an engine has been changed. I went thru auto school in '69-'70 when these cars were on the road as daily drivers and there was plenty of fixin to be done-way more than todays cars, but also easier work to do. Sure, I prefer original/unmolested, but mostly knowing that work hasn't been done-repairs often done poorly/wrong! I always look for 'tracks' of that past work-such as the often found studded rear head bolts used for engine grounds that are mislocated, ect-good luck! Dan Mpls. Mn.

If this swap was done over 22 years ago, it was probably common knowledge back then that the cranks were different and someone did the correct thing when making the swap. Perhaps the original block was cracked and all of the internals from the original '65 engine were used. Let's think the cup is half full, not half empty. With the car on a lift, pull the inspection cover from the transmission and look up into the area to which everyone is referring. I'd think if it was running good back then, there's no reason to think that someone cobbled it up when the swap was made. You could also get some other clues by comparing a '61 "stocker" to what you have in your car now. Same front cover, same water pump. Go through the list that Russ Martin has that tells the differences and see what you can learn.

Ed

Ed

Ed

This is all very interesting and gets to the core of the "numbers matching" mythology.

After 50 years each of these vehicles becomes a unique entity given its treatment over 5 decades.

A numbers matching vehicle can be poorly maintained, and driven into the ground, stored poorly, handled by incompetent mechanics.

A well maintained vehicle, properly restored by competent technicians, garage kept or dry climate vehicle is given second class status because of its engine being replaced.

Numbers matching is irrelevant because of all the other mitigating factors that define a vehicle's true condition.

Numbers matching falsely inflates a vehicle's value because it has nothing to do with a vehicle's history.

Sounding like a bunch of Camaro guys I know and exactly the reason I no longer have anything to do with Camaros and Chevelles.

This is all very interesting and gets to the core of the "numbers matching" mythology.

After 50 years each of these vehicles becomes a unique entity given its treatment over 5 decades.

A numbers matching vehicle can be poorly maintained, and driven into the ground, stored poorly, handled by incompetent mechanics.

A well maintained vehicle, properly restored by competent technicians, garage kept or dry climate vehicle is given second class status because of its engine being replaced.

Numbers matching is irrelevant because of all the other mitigating factors that define a vehicle's true condition.

Numbers matching falsely inflates a vehicle's value because it has nothing to do with a vehicle's history.

OK Dan: It's nice to finally hear from someone who agrees with me. Also.............

And, in the first place, the car in question is a 65? Mitch

Gentlemen, thank you all for the responses from both sides of the fence. I apologize for not replying sooner but I got busy with work and the family I'm sure you all have the same issues. All valid points made got me to thinking long and hard everyday since they were posted.

First off, yes this is a 1965 we are talking about. This car was my daily driver for many years before I parked it (14 years ago) due to having harmonic balancer problems... twice.

Now it is all starting to make sense. When the 65-401 was replaced with the 62-401 I am confident the mechanic did not torque the balancer to the 200+lbs it requires causing it to eventually start to wobble. When I replaced the wobbling balancer with a rebuilt balancer 9-12 months later it started to wobble too. I am confident I did not torque it the 200+lbs it requires because I was a young buck without a torque wrench & didn't know any better. When Larry Daisey (Rancho Riviera before he left Cali) sold me the second balancer & educated me on the torque specs I was already convinced I had an internal problem...14 years later I finally had a professional rebuild the motor for me and he reported I had no internal problems (except rust in the cylinders) but more importantly no damage to the crank shaft snout to worry about.

Lots of good information I gathered that you guys suggested:

-Intake manifold date code casting # found on the back half of the manifold is 1375549 there is a "B" above the number & a "2" below it. On the front there is a G 13. I didn't find these date codes in my book.

-The Carb "was" a Rochester 4 Jet. The only # I found was on the air cleaner flange and it reads 10 25 7

-Transmission # BR-65-28429 with a 59 above that. I think this is the original trans or do I have a Frankenstein car? lol

-No adaptors were used, no apparent butchering or machining. I put the flywheel & trans on so I took it apart so I can make sure. Looks like things were done right, I'm sure you guys will let me know...fingers crossed lol

-Torque converter and crank shaft recess mic'd #'s. I took the average of 3 different attempts. Crank recess: 1.700" Converter snout 1.694". I don't know how tight that snout is suppose to fit in the recess but that look pretty close...pls let me know...

-Here is a pic of the crank shaft while it was at the machine shop. Can this be the crank out of the original 65 block? I sure hope so...

I sure hope I covered it all...thank you once again gentlemen...you guys rock lol

I'm off to work for a couple of days. I will leave this apart just in case u guys have anything else I should be checking. Thx again

David

Dave,

Everything looks good, whoever did the engine conversion spent alot of extra time and was thorough, great news! It is very typical, when a Dynaflow engine is mated to a turbo 400, for the hole in the middle of the flexplate to be enlarged which eliminates the raised flange area and weakens the flexplate. I have personally experienced and heard of this from other members many times over the years...

Be sure when reassembling the flexplate to the crank that you align the small hole in the flexplate with the drilling in the flange of the crank as seen in one of your photos. This is also a very typical mistake when an engine swap takes place and results in an imbalance that will shake ones molars loose.

Is your diff a 3:23? If so, that`s a great gear for all around driveability, best of luck and GREAT pics,

Tom Mooney

I have a 425 from a '66 that's been rebuilt and is on an engine stand in the garage. Looks just like what you pictured. Breathe freely my friend, you're golden.

Dave,

Is your diff a 3:23? If so, that`s a great gear for all around driveability, best of luck and GREAT pics,

Tom Mooney

Thank you gentlemen…this feedback is music to my ears.

I don't think I have the 3:23 diff. That is a Posi right? I would like to get one…now that you put the bug in my ear again I will look into the prices on one again… I found one for $750 but I don't think is was a 3:23. Here is a pic of the stamping from the underside of my diff before I painted it. Its kind of hard to read & I didn't get much feedback when I first posted the pic for help in trying to figure it out.

My eyes could just be playing tricks on me but I swear I can make out what looks like a number "3" over what looks like a "23" right in the center lol wishful thinking right lol

3.23 came in openend and posi-i took a openend (3.23) out of my 63 and replaced it with a 3.23 posi.looks like a 3 over23 to me.Does your carrierhousing have a X in a circle on it or both axles move in same dirrection when rotated.I like the gearing ratio as tom mentioned.Theres also a way to check by # of rotation of axle to driveshaft-i cant remember formula but hopefully someone will chimein on it.goodluck.T.Nugent...

3.23 came in openend and posi-i took a openend (3.23) out of my 63 and replaced it with a 3.23 posi.looks like a 3 over23 to me.Does your carrierhousing have a X in a circle on it or both axles move in same dirrection when rotated.I like the gearing ratio as tom mentioned.Theres also a way to check by # of rotation of axle to driveshaft-i cant remember formula but hopefully someone will chimein on it.goodluck.T.Nugent...

Looks like you have a 3:23 gear. Given the trans code that is what I would expect and why I asked. With a posi rear one counts the number of turns of the driveshaft versus one full turn of the wheel. A 3:23 rear gear would produce 3.23 turns of the driveshaft for one turn of a wheel. This formula cant be used on an open rear end because the side gears are introduced into the equation.

Someone ordered that gear specifically. The standard gear with the 401 powerplant would be a 3:07. Is there any evidence of a trailer hitch? The evidence may be as little as a couple of holes drilled in the lower surface of the rear bumper or a modified rear taillight/stoplight harness.

Great all around gear to have, congrats,

Tom

I am very curious now…so u say I might have a 3.23 open diff here (fingers crossed, this trick worked when I checked if my engine swap was done right lol)? My book indicates the "X" in a circle should be at the bottom of this picture right? You can see the carrier housing edge if that's what your calling the housing. NO "X"in sight & NO my axles do not turn in the same direction which rules out a posi. So now I need that formula in order to check the ratio. We could be onto something here lol…Can someone help me with that formula pls

David

It's obvious our messages are being crossed.

Thank u thank u thank u…great news! I'm pretty happy with my "fingers crossed" technique lol.

So what are the other "888 18" & the big "70" numbers indicate? Nothing in my book on those. I am stuck at work & will have to check for trailer hitch evidence when I get home.

Does the "someone ordered that gear specifically" comment have something to do with why those other numbers are there? I'm guessing the other numbers were there for a different application until that "someone" requested the 3:23? Then the 3:23 was stamped later on upon the installation of the 3:23 gear?

You've got me loving the sound of… (Imagine a deep voiced Greek God echoing into a fade out saying) 3:23!!!!! lol

David

Maybe not a 3:23??? Here's a pic of my rear bumper with no evidence of the trailer hitch (no holes in the bottom & no altered wire harness except a new light socket someone put in).

But there is two holes in the bottom edge of the frame…hitches today are mounted to the frame but 50 years ago????

David

Hey, you're lucky if there are only holes in the frame. When I bought my '63, I got it from the original purchaser. He used it to tow a rather large Airstream trailer all over the country. It had a full hitch receiver welded to the frame. I also had to remove the electric trailer brakes from the car. Besides that he had modified the car for towing by installing an auxiliary transmission cooler, a full set of direct reading guages - oil, amps, temp, tach, and vacuum - in the slot where the ashtray goes. It was actually a very neat installation. You could close the ash tray lid and hide all the instruments. They had their own lighting and a switch to control just those lights. It had factory air shocks (dealer) installed, and a plastic disk that covered the speedometer with a set of numbers on it that indicated the actual speed of the car. He had also installed a 3.91 rear gear so that he wouldn't lug the engine while towing the trailer.

Good point. Your right…I'm glad I didn't have any cutting or torching to do. Sounds like you had a towing monster when u bought it lol

It's still unclear to me tho…are the two holes in the bottom of my rearmost frame rail the evidence Mr Tom Mooney had me looking for indicating a tow package with the 3:23 diff gears?

David

It's too cold to go crawling around under a car with a flashlight to answer that question at the current time.

Good point. Your right…I'm glad I didn't have any cutting or torching to do. Sounds like you had a towing monster when u bought it lol

It's still unclear to me tho…are the two holes in the bottom of my rearmost frame rail the evidence Mr Tom Mooney had me looking for indicating a tow package with the 3:23 diff gears?

David

Dave, the comment regarding a hitch was just a hunch on my part to possibly explain the 3:23 gears. I asked about holes in the bumper because the factory hitch mounted to the rear bumper. I think I still have a couple of them in the garage which I removed from Rivs over the years.

Tom Mooney

Ok, I get it. Not a big deal but we really don't have a concrete way to figure out if this is a 3:23 open diff right?

David

I have the matching holes in my frame, I wanna say I have the 3.07 gears because I saw the PB stamped somewhere but now I cant find it. I did have 33ID stamped on the axle housing but cant find anything on the carrier itself.

One way for sure it to drop the rear end and count the gears. Sometimes the numbers for both the ring gear and the pinion gear are stamped on the ring gear.

The other way is one that I saw on the H.A.M.B. and found again. Here it is. No guarantees on this, I'm just pasting what I copied.

For an open (non-posi) rear leave one tire on the ground and turn the driveshaft (mark it) until the other tire (mark it too) that is off the ground rotates exactly TWO times. The reason for the two tire rotations is because the spider gears are a 2:1 ratio. The number of turns of the driveshaft will be your gear ratio.

You might also do a Google search or check YouTube.

Ed

10 minutes later: Here's a YouTube video I found in which the guy determines the ratio of an open rear end. Same approach as above but by rotating the tire ten times, he's able to take the guess work out of what fraction of a revolution the drive shaft turned.

@Chris, same with me. I only found stamped numbers on the axle housing no letters only numbers & nothing on the carrier itself.

@Bernie, awesome youtube link, thank you. I will be trying that soon and I will post my findings.