[vertbird]

Guys, I have the chance to get a 79 block coded xx. I haven't seen it in person but looks clean and is said to be unbored. He's asking $600, does this seem reasonable? I understand the XX block is supposed to be stronger than my 557 block in my 76 TA.

[performerrpm]

in my area oklahoma thats a pretty reasonable buy if the blocks good.. it is better than your 557 block for sure. i have a xx block out in my shed now

[chiefbigb]

Prices are all over the place. That's not crazy for a good block.

[Dragncar]

Offer him 500 $ and see if he bites.

[kingbuzzo]

pontipig blocks are scarce as hen's teeth around here...I'd hit it

[Baron Von Zeppelin]

I don't think it can be a 79 model engine.
Hopefully that won't really matter overall .
Maybe its 77 or 78
Pontiac stopped casting 400 blocks in 1978

The 79 TA/Formula 400 used engines held back from 1978

[GTOLiam]

For my area that's a good and fair price

[4zpeed]

Originally Posted by Baron Von Zeppelin

I don't think it can be a 79 model engine.
Hopefully that won't really matter overall .
Maybe its 77 or 78
Pontiac stopped casting 400 blocks in 1978

The 79 TA/Formula 400 used engines held back from 1978

All 481988 XX 400 blocks were cast in 77 and used for W72 Performance Packages in
78 and 79 with a 220 hp rating, 568577 was used for 77 W72's with a rating of 200 hp.

The beefier 481988 used from 70 thru 74 was brought back into production due to
concerns over increased HP as the 568577 was known to utilize thinner webbing.

As mentioned earlier, can't hurt to make an offer, it is a good later 400 casting.



Frank

[78w72]

Originally Posted by 4zpeed

All 481988 XX 400 blocks were cast in 77 and used for W72 Performance Packages in
78 and 79 with a 220 hp rating, 568577 was used for 77 W72's with a rating of 200 hp.

The beefier 481988 used from 70 thru 74 was brought back into production due to
concerns over increased HP as the 568577 was known to utilize thinner webbing.

As mentioned earlier, can't hurt to make an offer, it is a good later 400 casting.



Frank

568577? Did you mean 500557 casting?

[Baron Von Zeppelin]

Is XX the stamped code on the front face of block - or something else ?

The only 400 code in 79 was PWH
Think mine was cast in Feb 78

[78w72]

Originally Posted by Baron Von Zeppelin

Is XX the stamped code on the front face of block - or something else ?

The only 400 code in 79 was PWH
Think mine was cast in Feb 78

Pretty sure hes calling it a XX block due to the casting #, he mentions it being stronger than his 500557 block, most people call these 78-79 W72 blocks XX. If its a 79 its PWH.

As for value, that can vary depending on condition, location & timing or just how bad the seller wants to get rid of it. $600 isnt too bad today if its in good shape & standard bore or will clean up to .030. I just sold a PWH block last year for $500 that was at .040 and needed bored to .060, it sold pretty quick.

[PAUL K]

400XX block had XX in various places. By the 400 block ID and in the valley area where a standard 400 block usually had 00 they have an XX. Also by the block casting number.

Blocks price vary by location. I posted a want add a while back and the prices varied from $300 to $800 for a fully machined block that took months to sell, or may have not sold yet. We would sell them for $400 as a core to a guy building a 78 or 79 TA.

[4zpeed]

Originally Posted by 78w72

568577? Did you mean 500557 casting?

Yes 500557 sorry about that. The later 481988 XX castings are easily confused
because of casting dates. None are known to be cast later than November 77.



Frank

[Skip Fix]

78 auto is an X7 found one complete years ago so if I ever want to make mine how i ordered it(I was too late for the W72 and an auto) I could. Previous owner painted it black.

[4zpeed]

That's the 568577 casting, basically the same as the 500557
they're all considered 557's because of the thinner webbing.



Frank

[78w72]

The 78 X7 is also a 481988 XX block for the W72 cars, the 4speed is WC.

[Skip Fix]

Yep, my original 180 HP 400 is a 557

[PunchT37]

Good block. But, more valuable in a `78 to `79 W72 400 Trans Am app.

[4zpeed]

After reading this again I wanted to clarify what's been posted

Originally Posted by 78w72

568577? Did you mean 500557 casting?

This is true when it comes to the OP "vertbird's" car, as it's a 76.
The 500557 casting number is used for the 75 and 76 models.


What I have posted here only pertains to castings from 77 - 79.

Originally Posted by 4zpeed

All 481988 XX 400 blocks were cast in 77 and used for W72 Performance Packages in
78 and 79 with a 220 hp rating, 568577 was used for 77 W72's with a rating of 200 hp.

The beefier 481988 used from 70 thru 74 was brought back into production due to
concerns over increased HP as the 568577 was known to utilize thinner webbing.

As mentioned earlier, can't hurt to make an offer, it is a good later 400 casting

The 568577 casting number is correct for the base 77 and 78 models
like "skip's" as well as the 77 W72 Performance Package. The 481988
was only used for the W72 Performance Package for 78 and 79.



Frank

[4zpeed]

......