# W72 Engine - worth building for a 67 GTO?



## cloverskull (9 mo ago)

Hey friends,

My new-to-me GTO has an engine that is in need of a rebuild. The block has "X7" stamped, which I believe makes it a 1978 T/A 400 block. My question is, are these blocks worth building? Are there significant differences in these blocks and a period-correct block? Any gotchas I should be aware of?

Thanks!


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## Boomstick (Sep 13, 2021)

They arent as strong as the older blocks. Some say they are only good to 500hp. I have a '77 400 thats going in my 69 here soon since i have no plans to exceed 500hp... I'm doing eddy heads, rpm intake, 750 holley and 068 cam in it...


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## armyadarkness (Dec 7, 2020)

Any 400 is worth rebuilding. For that matter, any Pontiac engine is worth rebuilding. But unless you need a specific one for a specific task, it may not be cost effective or feasible. The car will be worth more with a Pontiac engine in it, so the extra costs involved with building one, will be worth it some day. However, you'll either have to build it yourself or find a reputable builder... which is obviously MUCH MORE difficult than ordering a small block chevy from Summit.


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## Boomstick (Sep 13, 2021)

armyadarkness said:


> Any 400 is worth rebuilding. For that matter, any Pontiac engine is worth rebuilding. But unless you need a specific one for a specific task, it may not be cost effective or feasible. The car will be worth more with a Pontiac engine in it, so the extra costs involved with building one, will be worth it some day. However, you'll either have to build it yourself or find a reputable builder... which is obviously MUCH MORE difficult than ordering a small block chevy from Summit.


my 350 is going to be getting bored and stroked while its out and stored as a spare. its a shame no one makes a pontiac crate motor that is affordable to the regular joe. sure you can get one from butler, but it will cost you 4 months salary... even their 557 short block is ridiculously expensive


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## armyadarkness (Dec 7, 2020)

Ive been trying to buy a Pontiac motor for more than a year. Everyone wants stupid money for them, because they know what theyre worth, but Im not paying $800, for a core, from an internet stranger.


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## Boomstick (Sep 13, 2021)

armyadarkness said:


> Ive been trying to buy a Pontiac motor for more than a year. Everyone wants stupid money for them, because they know what theyre worth, but Im not paying $800, for a core, from an internet stranger.


I got lucky on my 557, got it for an even grand on a stand and running. its got "the biggest flat tappet you can get for a pontiac" (sellers words). It's radical, but too radical for what i want to do with my car so its getting an 068. the intake is factory pontiac no egr and its got 6x-8 heads on it now. i'm probably going to be selling everything off it (intake, carb, water pump, etc) and only using the long block. everything off my motor will go on it and the 69 350 is getting redone. or i may just sell the 350 the way it is after i get the 400 in. there's really nothing wrong with it other than it smokes a little at WOT...


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## geeteeohguy (Feb 2, 2008)

The '577' late blocks like yours are not as strong or desirable as a '67-'74, which is superior. That said, They haven't made Pontiac 400's in over 40 years and beggars can't always be choosers. I would have zero issues building it for a street car. As stated, it will handle a decent amount of power.


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## PontiacJim (Dec 29, 2012)

cloverskull said:


> Hey friends,
> 
> My new-to-me GTO has an engine that is in need of a rebuild. The block has "X7" stamped, which I believe makes it a 1978 T/A 400 block. My question is, are these blocks worth building? Are there significant differences in these blocks and a period-correct block? Any gotchas I should be aware of?
> 
> Thanks!



The TA block should be a good one as they cast the older type block to replace the weaker "557" block in the TA. Look for "XX" in the lifter valley and the casting number on the back passenger side below the head which should be XX481988. This block is just like the earlier Pontiac 400 blocks and plenty strong enough.


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## cloverskull (9 mo ago)

Awesome, thanks for the feedback everyone. Considering I have no idea what's inside this thing and no idea what condition it's in, I think I'll pull it and break it down and build it from scratch. I hope people here like pics 

Plans for now - roller cam, aluminum heads, intake, sniper EFI. Undecided on rotating assembly. TKX trans. Will be fun!

Oh, has anyone done an EPAS install on a GTO? I have one in my Mustang but as folks here can probably imagine, everything is possible for cheap on a Mustang due to abundance of cars and parts. I assume anything GTO will be more custom.


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## armyadarkness (Dec 7, 2020)

cloverskull said:


> Plans for now - roller cam, aluminum heads, intake, sniper EFI. Undecided on rotating assembly. TKX trans. Will be fun!


I hope you plan on robbing the stage coach. Gonna take a lot of gold for those mods! But, we all do it, every day... and the key to it all is attitude and determination, which it sounds like you have. Anxious to see it unfold.


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## Eric Animal (Oct 28, 2007)

armyadarkness said:


> Ive been trying to buy a Pontiac motor for more than a year. Everyone wants stupid money for them, because they know what theyre worth, but Im not paying $800, for a core, from an internet stranger.


What motor do you want/need? I have a good friend that mostly builds Pontiacs. He also has blocks, heads, etc....unfortunately, we are in NY on Long Island. So shipping will most likely suck. Maybe we can help.


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## armyadarkness (Dec 7, 2020)

I'm only 1.5 hours from Long Island! Most of my family is still in North Jersey, even closer.

I'll take anything from a 326 up. The bigger the better, but Im not too picky.


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## Boomstick (Sep 13, 2021)

armyadarkness said:


> I'm only 1.5 hours from Long Island! Most of my family is still in North Jersey, even closer.
> 
> I'll take anything from a 326 up. The bigger the better, but Im not too picky.


I wonder if a 400 long block would fit in my trunk... Hmmm...

I have a idea!!!

I'm right down the road a little bit in Martinsburg WV. Maybe we'll work a deal where I come to your garage, you help me swap this 400 into my 69 and I leave the 350 with you and drive home...


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## armyadarkness (Dec 7, 2020)

Boomstick said:


> I wonder if a 400 long block would fit in my trunk... Hmmm...
> 
> I have a idea!!!
> 
> I'm right down the road a little bit in Martinsburg WV. Maybe we'll work a deal where I come to your garage, you help me swap this 400 into my 69 and I leave the 350 with you and drive home...


That would be sweet!!!!!


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## skyking90 (Aug 6, 2021)

armyadarkness said:


> Ive been trying to buy a Pontiac motor for more than a year. Everyone wants stupid money for them, because they know what theyre worth, but Im not paying $800, for a core, from an internet stranger.


So the 68 Pontiac 400 complete engine that I have had sitting in my shop for bout 30 years might be worth some bucks? Have the tranny too. Some kid had a 68 firebird and his buddies told him he needed to put a chevy 350 in it and build it to go fast. I think it had less then 70k miles on it. I got the whole drive train including drive shaft. won't tell you what I stole it for. All I know is he probably spent a lot of money to get back to where he was.


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## armyadarkness (Dec 7, 2020)

I always tell people that the primary determining factor, when considering value, is location.

A numbers matching 69 Judge with a 4 speed and 30 original miles, wouldnt be worth much to guy with no left foot.

But in my opinion, the real problem with engines is; once it's out of the car, it's near impossible to easily or adequately determine what condition it's in, so you're it buying 100% based on faith, which in case you hadnt noticed, is now in short supply... thanks to these foreign ass-clowns and their iphone app scams, which for some reason we do nothing about...

And then theres shipping to consider. If youve never shipped an engine, it's not so fun... and right now, the shippers have decided that raping us is a nice way to help us get through these hard times.

That being said, if you live within a 3.5 hour drive of Atlantic City, and you dont own a turbin and a credit card skimmer, then we should talk!


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## armyadarkness (Dec 7, 2020)

BTW, yes a Pontiac 400 and trans has great value to most of us here, for obvious reasons. Im looking for something to rebuild, but a low milage, clean running engine would be worth a considerable amount.

On facebook market place, everyone is asking big bucks for them... but they're also asking big bucks for engines which have been sitting outside for 20 years, which to a machinist is worth nothing.

And many of the guys in here buy these engines, only to get them home and discover that they paid Pontiac money, for boat anchor goods.


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