2020-B1-8

Author Topic: 74 400 488988 block  (Read 214 times)

case1175

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74 400 488988 block
« on: April 05, 2020, 03:36:04 PM »
Why does this block number not show up in most Pontiac engine look up sites? Odd ball engine?
It is definitely Not a 481988 block

firebirdparts

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Re: 74 400 488988 block
« Reply #1 on: April 06, 2020, 07:45:24 AM »
I don't know how we'd ever know.  I trust wallace racing, and they have a note in their database that says "send us info".  488986 is a 1974 350, so the very first question is could that be a 350?   I've also never found any mistakes in Pete McCarthy's book, and he doesn't mention anything about it being an actual part number.  I think we can be reasonably sure that there wasn't an improved version of the block.  That would have interested McCarthy for drag racing.

The bucks had a block casting number plate screwed or nailed on, and in fact you can see the big panhead screws on an engine.  They were "temporarily permanent" since the part number for that block didn't change for years.  If somebody got one wrong they might have made a lot of wrong castings.

Extra info:  I have observed in the 25 years of the internet that any mistake made by anybody gets copied everywhere in databases and decoders, and so I always encourage wallace racing's decoder.   They are the best that I have found.
« Last Edit: April 06, 2020, 07:47:28 AM by firebirdparts »
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

Maxthe222

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Re: 74 400 488988 block
« Reply #2 on: April 06, 2020, 03:50:53 PM »
What are examples of some websites it does not come up on?
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula 400 4-Speed

case1175

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Re: 74 400 488988 block
« Reply #3 on: April 07, 2020, 07:51:44 PM »
Ive bin e mailing John Wallace at Wallace racing. Even he seems a little stumped. 400 stamped on engine. So not a 350. Can’t name all sites I looked at. Googled 74 Pontiac 400 engine. Went down the list of sites on the first couple pages. Not much on that block number.

Maxthe222

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Re: 74 400 488988 block
« Reply #4 on: April 07, 2020, 08:06:52 PM »
Well those links I sent last time did include a link to wallace racing, and on a section of his website was this page:
http://www.wallaceracing.com/blockcastnum.htm

Which shows that cast number in 1975. On the same wallace racing website, when you go to the code search, YM is used both in 1975 and 1974, and both are for automatics. They are the same block. The same block ]was reused or just still in use when 1975 cars were built in 1974 as they may have just had a surplus.

On all the links provided, it all said it was a 400 and both evidence that it is a 400 488988 code. The block for a 350 and 400 is basically the same, they may have just made a bunch of blocks and bored some to 350 specs and some to 400. So on his own website he has those engines with the YM Id number on them, and the corresponding 488988 number.

Plenty of engines haven't been exactly documented to the letter and each individual code on them. Some engines have the cast code 488986. Some are cast as 481990. It was just a number that changed that could be due to a number of reasons, such as retooling the machines, differentiating blocks or stock, it likely was not a mistake or an oddball block, it's just... a block
« Last Edit: April 07, 2020, 08:09:27 PM by Maxthe222 »
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula 400 4-Speed

Rocky Rotella

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Re: 74 400 488988 block
« Reply #5 on: April 14, 2020, 10:08:20 AM »
I have a 488988 block in my garage that I’ve owned for years. It was cast in 1974 and its dimensions are all standard. I, too, have seen online references to the 488988, but have never been able to determine its origin. And never once had I found that part number in any of my Pontiac materials. I’ve kept it around because I always wondered what unique characteristics separated it from the typical 481988 400-ci block of the era. During my visual inspection, I simply couldn’t find any.

Several years back I purchased a few internal Pontiac engine assembly manuals, which engineers used to note every component used to assemble every engine, by part number and engine application code. And then while writing my 1970-1981 Firebird book, I was able to purchase several sets of blueprints from a former Pontiac engineer. Both have detailed information on the 1974 model year engines and there’s no mention of the illusive 488988 block.

At this point, I believe that the 488988 casting was simply a foundry error as someone inadvertently combined the part numbers of the 481988 400-ci and 488986 350-ci blocks while prepping the mold patterns. I’d love to hear if anyone can find anything more conclusive though!

Re: 74 400 488988 block
« Reply #5 on: April 14, 2020, 10:08:20 AM »
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