Author Topic: Tracking down original W72  (Read 924 times)


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Tracking down original W72
« on: July 07, 2017, 11:53:53 PM »
Howdy folks,

Anyone have any good methods of tracking down a W72 engine? I know the car was bought in Canada, I've got the VIN, PHS documents but that's about it. I'v heard about something in Canada that you can use to get a list of all previous owners, but I think the car only has one previous owner.

Also, how do i tell the difference between a L78 400 Pontiac and the W72? I've tried reading into it, but what I've learnt is it's something to do with chromed heads and here is a certain number stamped on the body somewhere like "XA". If I do end up stumbling across an engine that could be from the T/A i'm looking at, i'd like to make sure I know how to tell if it is from the original car.

Thanks in advance for all the help!


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Re: Tracking down original W72
« Reply #1 on: July 08, 2017, 12:27:52 AM »
if it is from the original car it will have the engine number which will match the vin number
for general W72 info this article will help
1978 Y84 W72 WS6


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Re: Tracking down original W72
« Reply #2 on: November 27, 2018, 04:07:24 PM »
77 W72s used a no.500557 block, 78 W72s used a no.481988 block- both used 6x-4 heads. The stronger 481988 casting was brought back because of TAs coming back
due to engine problems (cracked main saddles). L78s used a 500557 block and 6x-8s. Not sure if the 77 W72 blocks had the 'XX' raised letters in the lifter valley and back of the block, but I know the no. 481988 blocks used in 78-79 did.

1977 SE T/A (sold :( )
1974 455 T/A (sold :( )
1972 Esprit restomod
1976 T/A restomod
1975 Formula 400 4-speed donor car
1978 Martinique blue W72 4-speed T/A, hurst tops


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Re: Tracking down original W72
« Reply #3 on: November 28, 2018, 07:48:33 AM »
Yeah, like Geno said, a '78-'79 W72 will have an XX 481988 block.

There was only one 400 block used in '79. It had a PWH code & came only with a manual trans.

In '78, manual trans W72 blocks had a WC code, and auto trans W72 blocks had an X7 code.

In '77, man trans were WA, auto trans were Y6, and were casting number 500557.

The last 6 numbers of the VIN of the car the block came in will also be the last 6 numbers stamped(sometimes very lightly & hard to read) vertically, down beside the timing cover, on the passenger side, near the bottom.

« Last Edit: November 28, 2018, 07:58:02 AM by oldskool »

Re: Tracking down original W72
« Reply #3 on: November 28, 2018, 07:48:33 AM »
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