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Help In Identifying A 1973 455 Stage 1


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I am not a Buick guy, but please don’t hold that against me. I am after all a car guy, so please be patient.

I have an “opportunity” to pick up what is alleged to be a 1973 Buick 455 Stage 1 via an “angry wife distress sale” scenario. The engine is purported to be from a long-gone ’73 Riviera GS. I want to be certain that this engine is what it is claimed to be since I am concerned that the owner might be “putting lipstick on a pig” to persuade me to haul it off. But the wife has demanded that it be moved out of the basement and into the rain, and I don’t want it to get ruined if it really is of use to someone.

So here are my questions:

Was a 455 Stage 1 engine indeed offered in ’73?

How do I identify it as a 455 and as a Stage 1? Please understand that I do not even know where the “important” numbers are located on a Buick engine, much less what they represent.

What unique Stage 1 pieces should be present (intake and exhaust manifolds, heads, etc.)? And can you offer casting numbers which might identify them as such?

Are there other characteristics I should look for to determine if this is a good rebuild candidate for a Buick enthusiast (aside from the absence of a hole in the side of the block)?

Were these good engines, or does some deficiency (such as a cast crank) mark them as red-headed step children to those who are “in the know”?

This same individual also has what he claims to be a set of Stage 1 heads (year unknown) and a bare ’69 Buick 350 block which he wants gone. Same question: where do I find the numbers to identify them as such, and what might those numbers be?

Thanks in advance for your help.

Jeff Dreibus

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The 73 Riv Stage 1 Engine code is XA. This will be stamped on the block face (as in where the head gasket rests) on the driver side of block between the spark plugs. Either between the 1st or 2nd or 3rd and 4th plug. Can't recall without researching. They only made 1234 of these so finding one would be quite rare. I would not delay in going and checking the number. Let us know what you find.

I'm not sure about what the head casting number was for the stage one in 73. If its an XA block and the block and head date codes are within a month either way theres a good chance they are the original heads.

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Guest BJM

All 455 Buick engines are hardy strong motors extremely well engineered except for an oiling issue in 1970, which was corrected by 1971-72.

My understanding of the Stage 1 'option' is that it included internally ONLY larger intake and exhaust valves and a hotter cam.

It should include a recalibrated four barrel and distributor BUT I am not sure about 1973, as the option and muscle cars generally were on the wane by 1973.

If you have a Stage 1 motor, it's in demand - period. Complete you should get good money out of it. If it's a 455 but not a Stage 1 - same deal, you should be able to get $150 to $250 for it.

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Jake and Jason,

Thank you so much for the timely and helpful input. I will take your advice and put it to good use pronto.

If it turns out to be a good rebuild candidate, I would love to have a boattail Riviera or a '73 Century GS into which to install it -- even though I am a Mopar guy! Unfortunately, I will probably end up selling it instead.


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Watch out, this Buick stuff is catchy! grin.gif One more little tidbit. In 1973 the Riviera GS option did not automatically include the Stage 1 engine as in 71 and 72. It had to be ordered separately. Because of this many get confused and assume if its a 73 GS it has the stage 1. So the engine could have came from a 73 Riv GS, but not necesarily be a Stage 1.

Even if you can't use it and sell it, at least the engine will be transferred to a needy individual instead of being sent into a black hole somewhere.

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Okay, guys, I just checked this engine out as best I can.

It is not stuck, but the carb and the ring gear are damaged from rough handling. There is probably more damage, but I can't be sure due to the amount of dirt collected upon it from being dragged through the mud. Yeah-boy, nothin' but TLC . . .

As far as the numbers go, the code located between the third and fourth plugs on the driver's side is:



On the pad in front (pass. side) is the following:


So what do I have here, and is it worth salvaging?

BTW, I saw the 350 Buick block (allegedly a '69) and it does contain the rotating assembly.



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Sorry, Yep like Roberta said, Its a standard 1974 Riv engine. In 74 the Stage 1 Riv had a ZA code.

I would have been surprised if it was a stage 1 due to the rarity.....but you gotta follow these leads through.

If you can get it for free it might we worth the trouble of hauling it around and cleaning it up if you having nothing else to do. Since there is zero history on the internals and from your description, looks bad, assume the worst and expect to get $100 for it. If you had confirmation the block, heads and crank were OK then you could expect to get more.

There are always exceptions like if you're lucky enough to find someone very desperate for a 455 block you may get a little more.

I'd probably pass on this one unless you had a buyer waiting. Thats just one persons opinion though.

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  • 1 month later...
Guest Thadd McNamara

I built a stage II for my wifes 36. Someone at the restorationshop stole it, and the shops insurance came up with just south of $12K to replace it

I went with a 96 Roadmaster LT1 4L60E combination that is probably going to be at least as quick as the 464, and will get better gas mileage too...

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