LX Code 425 vs MW code 425

[Guest Rob J]

Is there any real difference between these two longblocks? Obviously I realize that the LX engine had the dual quad setup, and the MW did not, but is there any real difference in anything else other than the dual quad intake, carbs, ect...

I had a guy look at this car for me today, and as it turns out, it had a MW coded engine block, and not the proper LX. From my research, it appears that the MW 425 was the base 425 in a 66 Riv. Is this correct? It's too bad, as it had the proper coded carbs and rear end on it. He was not able to get to the transmission to check for the BS tag, however. I was going to be able to buy this car for a pretty good price, but with it not having the LX engine, I got my deposit back, and walked away. The seller was understanding, and apologetic. I honestly don't think he was trying to scam anyone, he just honestly didn't know too much about these cars.

Here is the car I was looking at. Some of you may have seen it for sale.

It's on Craig's List in St. Louis now. I live in Miami, FL

Buick : Riviera - eBay (item 200537011075 end time Oct-31-10 20:09:29 PDT)

[Dales90]

Hi,

somewhere in the deep folds I seem to remember, many 66's with dual quads could have been dealer installed......therefore w/o LX code

Dale

[Patrick91914]

Is there any real difference between these two longblocks? Obviously I realize that the LX engine had the dual quad setup, and the MW did not, but is there any real difference in anything else other than the dual quad intake, carbs, ect...

I had a guy look at this car for me today, and as it turns out, it had a MW coded engine block, and not the proper LX. From my research, it appears that the MW 425 was the base 425 in a 66 Riv. Is this correct? It's too bad, as it had the proper coded carbs and rear end on it. He was not able to get to the transmission to check for the BS tag, however. I was going to be able to buy this car for a pretty good price, but with it not having the LX engine, I got my deposit back, and walked away. The seller was understanding, and apologetic. I honestly don't think he was trying to scam anyone, he just honestly didn't know too much about these cars.

Here is the car I was looking at. Some of you may have seen it for sale.

It's on Craig's List in St. Louis now. I live in Miami, FL

Buick : Riviera - eBay (item 200537011075 end time Oct-31-10 20:09:29 PDT)

If you were looking for a GS, then you were right to have walked away. I'm not convinced that the car is a GS not becuase it doesn't have the LX motor (which could have been replaced over the years), but becuase glove box plate reads "Riviera by Buick" when it should read "Riviera Gran Sport." For someone trying to clone a GS that could be one of the hardest parts to find.

Also, if this is a number matching car, then it's not a GS. I'd bet a paycheck that it doesn't have the correct tranny.

Further this car is a rust bucket not worth the investment, IMHO.

[Guest Rob J]

Yep, the non GS glove box tag was the first thing that stuck out in my mind when I saw the car for sale. I figured it was still worth the shot to take a look at it, as I figured at some point the glove box could of been changed, who knows. It did have the correct rear end, but we were not able to check the transmission.

I'd buy the car for $500 or so as a parts car, but that's about it. I don't think this car is worth any more than $750 or so. My guy did tell me that the interior was in pretty good shape however.

OH, BTW, it was not a numbers matching car. The engine HXXXXXXX number and the VIN HXXXXXXX were different.

[RivNut]

Chances are it's a good thing the engine code didn't pan out. I'm of the opinion that if this truly was an original Gran Sport, it wouldn't be for sale on Craigslist, nor would it be selling for only $3K. If something sounds too good to be true, chances are it is. After looking closely at all of the pictures again, that car is a REAL project. If there's that much rust showing on the exterior, just imagine what's hidden underneath.

In reference to your other question - there is only one physical difference between a '65 and a '66 425. The '66 had valve seals on the intake valves, but that would have been on the heads only; the blocks would have been identical except for the code stampings.

Too bad there wasn't any paper work on the engine swap. A friend of mine has a '65 GS in which the block doesn't have the correct LX or VIN; BUT he does have the dealership invoice that shows the engine was replaced under the original warranty. He's still in good shape.

Edited November 21, 2010 by RivNut (see edit history)

[Guest Rob J]

I totally agree with you on the "too good to be true thing". Which is why I really researched what to look for on these cars, and I had somebody go out and look at all the numbers on the car. I was skeptical.

The dual quad setup is correct, so the value in that car IMHO, is most likely what a non running dual quad set-up would sell for. What about $750 or so? Maybe a tad more.

I agree with you on the rust issue. It looks rough at best, and did you see the snow tires on it? I was most likely planning on buying this car just for the running gear, as the body is mostly junk.

Edited November 21, 2010 by Rob J (see edit history)

[Patrick91914]

I totally agree with you on the "too good to be true thing". Which is why I really researched what to look for on these cars, and I had somebody go out and look at all the numbers on the car. I was skeptical.

The dual quad setup is correct, so the value in that car IMHO, is most likely what a non running dual quad set-up would sell for. What about $750 or so? Maybe a tad more.

I agree with you on the rust issue. It looks rough at best, and did you see the snow tires on it? I was most likely planning on buying this car just for the running gear, as the body is mostly junk.

A dual-quad set-up (air clearner, correct carbs, linkage, manifold, kickdown bracket, etc) goes for about $1500 and up depending upon condition. That's the value in this car along with the rear end, headlight motor, headlight bezels (if they're still there). . .the car's value as a GS (if it is) is gone simply becuase of the rusty carcass. The seats are crap needing new covers and need to be reubilt.

Anybody who has ever put together a '65 Riv GS knows that it's an expensive process. This is not the car to mortgage your house over.

Edited November 21, 2010 by Patrick91914 (see edit history)

[RivNut]

My thoughts exactly. I did see the Super Wildcat breather in the trunk. The intake, carbs, and breather might bring $1K if the carbs are good. The posi-trac rear is worth something as is the variable pitch transmission. The seats looked decent, as did some of the interior parts. For $3K, you could possible get your money out of parts IF it were already in your back yard; not worth transporting to part out though.

See if you can convince the guy that "the guys in the know on the AACA site" think it's only good for parts and ask him what he'd sell the drive train to you for. I also noticed that the fan shroud is missing and someone has installed a flex fan on the engine.

You'll have less $$ invested if you look for something that's already in good shape and driveable.

[Guest Rob J]

I had made a deal with him to buy the car for $2,750, and gave him a $250 deposit, pending the inspection of the numbers and codes. My guy went this morning to look at the car.

I told the seller that the car is not what I thought it was, and he gladly gave me back my $250 (paypal)

I called him about two hour later today, and said I'd still be interested in buying the car, but as a parts car, and not for $2,750 (because it will cost me about $700-800 to have it transported here to Miami, FL. He then told me a guy offered him the full 3k in NJ. He told me that he told the NJ guy that he had discovered it had the incorrect engine block, but he said the NJ guy still wanted it. I told him, well, if that deal doesn't pan out, call me back. I'd maybe give the guy 1k for the car, but not more than that, considering I need to pay almost that to bring it here.

And, We were not able to verify that it has the right tranny. It was too difficult for my guy to get under the car to read the tranny ID. He tried, but I told him to not worry, as it was too dangerous to get under there with only a jack. You really need to put the thing up on a lift to see the tranny numbers.

[Guest Rob J]

Hi,

somewhere in the deep folds I seem to remember, many 66's with dual quads could have been dealer installed......therefore w/o LX code

Dale

Dale, I did a bit more research, and it seems as if you are right. It appears that MW coded 425's were dual quads, but dealer installed dual quads.

Man, you guys know your stuff around here. I'm glad I found this place.

[RivNut]

All 425's in 1966 were coded MW. The MX designator was assigned to a 350 motor. The rare factory equipped MZ were the factory dual quad cars. There's nothing to designate a dealer installed 2x4 car. The dealer couldn't change the stamping.

Attached is a photo of the 425 from a '66 that I parted out, it was a single Q-jet carbed car.

If you need further proof, I'll scan the "how to indentify" page from my '66 shop manual.

[Guest Rob J]

Thanks for the clarification (and pics) Ed.

[JZRIV]

Is there any real difference between these two longblocks? Obviously I realize that the LX engine had the dual quad setup, and the MW did not, but is there any real difference in anything else other than the dual quad intake, carbs, ect...

The 425 factory dual quad cars (KX, LX and MZ,) had a different cam vs the standard 425. Other than that the internals were the same. The distributor was different as well. It was setup for a 12 degree initial timing setting vs the normal 2.5 degrees.

Edited November 22, 2010 by JZRIV (see edit history)

[RivNut]

What's kind of strange about the 65-66 dual four barrel "hotter" cam is that it has the exact same specs and is timed exactly the same as the OE '63 cam. Read this article that was written by Dennis Manner for the Riview a few years ago. There's some very interesting info on which OE nailhead cam is actually the "Hottest."

Ed

[1965rivgs]

Buick "detuned" the 425 single 4 barrel cam for `66 to obtain a smoother idle. They retained the earlier Super Wildcat cam for the factory built `66 Super Wildcat dual quad engine.

Tom Mooney