72 LS5 block question
Thread Starter
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Joined: May 2015
Posts: 97
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From: Chicago
72 LS5 block question
Am thinking about buying out of state 70 LS5 car but told block (289) is 72 with blank pad. Dealer says its most likely factory replacement and some blocks simply didnt have the CE stamp. True?? Never heard that one. Also, am told has original 70 heads and manifold. Do the 70 heads and manifold work with the 72 block? if the heads are correct, does that mean high compression pistons used? My concern is that this is still the high perf engine other than the block and not some watered down version. Would appreciate any advice. Thx.
Team Owner
Joined: Sep 2006
Posts: 31,267
Likes: 4,362
From: Westminster Maryland
Hi John,
Since the 3999289 block was used in car and truck applications and rated from 215 to 270 horsepower I don't think there's anyway of knowing what's in there at this point without taking it apart.
Almost every Chevrolet engine with no suffix code on the pad started life in a Corvette.
Regards,
Alan
Since the 3999289 block was used in car and truck applications and rated from 215 to 270 horsepower I don't think there's anyway of knowing what's in there at this point without taking it apart.
Almost every Chevrolet engine with no suffix code on the pad started life in a Corvette.
Regards,
Alan
Last edited by Alan 71; May 2, 2015 at 10:13 AM.
Thread Starter
Advanced
Joined: May 2015
Posts: 97
Likes: 4
From: Chicago
Thanks for the responses. Before I take a long trip to see the car I just wanted to know if 70 heads and manifold can be used on a 72 block. And if so, is the only way to confirm the high compression pistons were used is to do a compression test? Would the 70 heads even work with the wrong 72 pistons? Just not sure how all the pieces could or could not fit together on this engine.
Team Owner
Joined: Sep 2006
Posts: 31,267
Likes: 4,362
From: Westminster Maryland
Hi John,
A compression test indicates the condition of the rings, valves and valve seats, not the compression rating.
The compression rating is a ratio determined mathmatically.
Regards,
Alan
A compression test indicates the condition of the rings, valves and valve seats, not the compression rating.
The compression rating is a ratio determined mathmatically.
Regards,
Alan
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
Am thinking about buying out of state 70 LS5 car but told block (289) is 72 with blank pad. Dealer says its most likely factory replacement and some blocks simply didnt have the CE stamp. True?? Never heard that one. Also, am told has original 70 heads and manifold. Do the 70 heads and manifold work with the 72 block? if the heads are correct, does that mean high compression pistons used? My concern is that this is still the high perf engine other than the block and not some watered down version. Would appreciate any advice. Thx.
You may want to note the date codes on the castings, intake and heads if the owner will let you take of a valve cover. Also note the build date of the car as found on the trim tag. This may eliminate original heads and intake if the dates don't work out. Won't necessarily guarantee they're original.
Last edited by BBCorv70; May 3, 2015 at 05:12 PM.
Le Mans Master
Joined: Mar 2001
Posts: 5,738
Likes: 644
From: Lincoln, CA
Or spend $25 for this one
Here is a shot when I was looking inside the intake track.
Here is a shot when I was looking inside the intake track.
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Le Mans Master
Joined: Jun 2006
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From: Tampa Florida
Am thinking about buying out of state 70 LS5 car but told block (289) is 72 with blank pad. Dealer says its most likely factory replacement and some blocks simply didnt have the CE stamp. True?? Never heard that one. Also, am told has original 70 heads and manifold. Do the 70 heads and manifold work with the 72 block? if the heads are correct, does that mean high compression pistons used? My concern is that this is still the high perf engine other than the block and not some watered down version. Would appreciate any advice. Thx.
Good luck.
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
Am thinking about buying out of state 70 LS5 car but told block (289) is 72 with blank pad. Dealer says its most likely factory replacement and some blocks simply didnt have the CE stamp. True?? Never heard that one. Also, am told has original 70 heads and manifold. Do the 70 heads and manifold work with the 72 block? if the heads are correct, does that mean high compression pistons used? My concern is that this is still the high perf engine other than the block and not some watered down version. Would appreciate any advice. Thx.
Melting Slicks
Joined: Jan 2003
Posts: 3,029
Likes: 94
From: meraux LA
Unless the seller can prove otherwise, assume it's a non matching #'s car. You are going to get into the whole, original, number correct or number matching debate. If it does not have the VIN #'s on the engine block, then it's not the original engine. Just my .02. Best of luck.