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Warehouse Find LS-7


jeeper61

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the farmers i worked for in those years never had very good luck with them in their trucks, the 427s werent much better just couldnt keep them together for some reason - they had better luck wtih the 366s in the grain and dump trucks and 350s pulling the goosenecks - yes a sacrifice in power but more reliable for whatever reason, i didnt dabble with them back then i just drove them and listened to the cursing when things broke

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that LS7 ain't for no truck😏

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After playing a game of "find the power" with ignition timing, the LS-7 belched out a best pull of 582 hp at 6,000 rpm and 546 lb-ft of torque at 4,900 rpm. Yeah, that was running the tunnel ram, which is why the hp is a bit up from the advertised number of 522 hp and the torque is a bit down from the 600 lb-ft in the catalog. With these power numbers, it's no wonder the LS-7 is considered one of the Holy Grails of big-block Chevy mills.

it the baddest Performance crate motor GM had at that time

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8 minutes ago, searcyfarms said:

the farmers i worked for in those years never had very good luck with them in their trucks, the 427s werent much better just couldnt keep them together for some reason - they had better luck wtih the 366s in the grain and dump trucks and 350s pulling the goosenecks - yes a sacrifice in power but more reliable for whatever reason, i didnt dabble with them back then i just drove them and listened to the cursing when things broke

I am no expert, when we decided the 366 had had the radish, we came up with a 454 out of a 1 ton, thinking  it would be an easy swap, not so, absolutely nothing worked, it didn’t have bosses for bolt on accessories, cooling ports were WAY smaller, bell housing wouldn’t line up, pilot bearing was all wrong. The specific details escape me by now but they wouldn’t just switch like they do in a car or pickup. Ended up finding a 427 tall deck block and had it all rebuilt, .030 over, it was a real beast, never could keep manifold gaskets in it, but otherwise it was reliable. The 366 didn’t have enough power to pull a sick whore off a piss pot, i am not surprised they didn’t self destruct. 

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What would the application have been for this LS7? Were they put in anything factory? 
Camero? Vette?  

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1 hour ago, vtfireman85 said:

What would the application have been for this LS7? Were they put in anything factory? 
Camero? Vette?  

The LS-7 454 was never offered in a production car it was a Chevy Performance offering 

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How come I can never find a crate like that????????????

The ones I find are usually full of the busted pieces!!!

Mike

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I used to have the GM performance book for big blocks that had all the part numbers and engine codes, LS6 was the highest advertised hp available in a production car at 450hp, came as an option in Chevelles or Vettes, can't remember if others got it, some think the 427 L88 or ZL1 was wilder but not advertised as more hp by GM they came in Camaros and Vettes. An electrician I used to work with had a 70's Camaro that he put a LS7 into that he said was pretty fast, difference between the 6 and 7 if I remember was full floating rods, 1 compression point higher around 12.5 to 1, open chamber heads, and a hotter cam

The 427 tall deck truck motors had a lot of differences but some guys hot rod them, peanut heads gotta go, they had 4 bolt main blocks and forged steel cranks so good base to build on

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My brother has a L-88 in a 1979 Camaro NHRA Super Gas car. It is stripped down to weigh 2300 with driver. It has fiberglass nose, doors, and trunk lid, Lexan windows, aluminum floor and firewall, full tube chassis. It was too quick for him so it has been parked in his race trailer since 2010. I keep telling him he needs to sell the engine or complete car before it deteriorates to scrap value but he still has it.

 

The LS7 was never factory installed. It was an available option but from GM history records, only 1 was actually built and that was for testing/media showing off. Interestingly, GM has a new version of a LS7 but it is based off the new small blocks, and available as crate engine only. 

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The township road Commissioner I worked for liked the 366 in their C65 dump or spreader trucks. 5+2 transmissions, the '67 was geared pretty low, 55 mph was a good cruising speed, 60 was top speed. The '74 I drove ALL summer of '74 was geared just a touch faster, and struggled when loaded, would easily run up to 65 empty but needed a tail wind or long downhill to reach 65 loaded. 

   The '57 F750 Chassis we had under the spreader box in '73 for chipping or sanding oiled roads had a 292 V-8 and 5+2 and it actually ran really well considering it was 74 Cid smaller than the Chevies. 

    I forget what I was in town for a year or so later but a '75 or '76 C70 tandem with 427 emblems was sitting in the lot. But I was driving a '74 Diamond Reo 10-wheeler hauling concrete, probably the nicest "Big"truck I ever drove. 555 Come-Apart and 6 spd Allison and 3 speed Brownie 2:1 underwrite, direct, and 15% over-drive.  Like a 208 hp engine in a 22,000# empty truck could pull an over-drive gear!

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3 minutes ago, DR.EVIL said:

Like a 208 hp engine in a 22,000# empty truck could pull an over-drive gear!

If you had a tall enough tree to drop it out of....:rolleyes:

Mike

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1 hour ago, dale560 said:

Do any of you guys know if the 454 used in the heavy duty trucks from late 70s to mid 80s was the tall Deck like 427 was tall deck truck and lower deck auto and light truck.

I have researched the 454 (I have been around it since a 66 427 in a 66 Corvette), but have never found it in anything but a pick-up model derivative of a truck, based on my findings I don't believe GM had a 454 MEDIUM truck motor. (they probably had it in a cut-away bus and RV chassis but that is based on a pickup) There are major cooling differences between the high-block and pickup/car versions of the BB. GM redesigned the 454 (pickup) low-block block in 92 for cooling and oiling improvements but they continued with the 366/427 high block for all their medium duties (possibly forged crank and rods)  so for as I can determine.  I have also not found any official GM data on exact mods they made but the cooling passages in the after 92 heads are different and all 454 blocks have 4 bolt mains and full circle rear main seals. They did have the 496/8.1 engine in some models from around 2000 to when they got out of the medium duties in 2008.  I have never cared enough about that derivative to spend time on research, it was in the school bus chassis but that is the lightest application of a medium duty truck, so my assumption is that it is based on the 92 low block BB redesign. My reason for recent research is that I wanted to use the after 92 block and some 60's high flowing 427 heads to produce decent power because the after 92 heads don't flow for high performance applications. The aftermarket heads available are supposed to fit pre and after  92 redesigned blocks but how would that work with different cooling ports in the blocks, The solution is supposed to be a conversion head gasket, that I found a reference to, I pass on that idea!.

 

 

 

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2 hours ago, dale560 said:

Do any of you guys know if the 454 used in the heavy duty trucks from late 70s to mid 80s was the tall Deck like 427 was tall deck truck and lower deck auto and light truck.

I've seen them in plenty of ton n a halves and 2 ton water trucks and dump trucks i always thought they were stock but like was said there is no evidence of them coming from the factory that way, as far as the 427 tall deck there was also a marine version that is even thicker that the truck version these are the only two i know of they will go in a pickup alright and are a little tight in a car but i have done it, my brother had a book and it said that g.m. ran out of truck engines and put some of these in trucks i owned two tall decks and the second one was a marine engine out of a truck, didn't realize it until it was being cleaned up at the machine shop and it had marine cast into it

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Chevy most definitely sold new trucks with a 454 engine in a up to 3 ton chassis. i have seen 4 or 5 put plugs and rotor, dist caps on them.  and other tuneup stuff. They seem to be available in two time periods. Late 70s from around mid 77 to 79 and again in the early 80s like 81 to 85. I have seen brochures and will post one later of the availability. I just never paid attention if the 454T for truck  was built off the tall deck 427 block. You see all types of no answers but there are a couple of posts on the internet that explain a chevy truck 454 was available off the 427 block just needed the 454 crank and pistons with pin in right spot. Like building a 466 out of a 436 IH block. And as for low deck bolting 454 into a 366 it shouldn't be that difficult with the right manifold and accessory brackets. AS far as i know the bell housing pattern is the same and most big blocks used a bell housing that fit transmission application. front water pumps and acc drives could be different though.

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 had one in a 73 c25cs       7 mpg loaded empty/  0 -70 didnt care,  the first efi/ etc made that 15 mpg + until they changed recracking for tax $

when gas went from .35-to .85    it went into a dirt car    

on that note ,when oil was  $130-160b  gas was $380-410    .......now at $65b  it is still $3.80   as by law it cant be less then $299 + tax

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About 2010 I bought a couple of TD-40s from a guy that had a cherry 80’s Chevy Suburban with a factory 454 in it. He had no interest in parting with it. Don’t know what I would have used it for, but I’ve often thought about it. 

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19 hours ago, hardtail said:

I used to have the GM performance book for big blocks that had all the part numbers and engine codes,

Back in the day....(late 60's) local dealer did some drag racing. GM would not admit to being in racing, but they did have 'the book' if you needed hot parts. I was told that this book was somewhat limited as to who had (or could get one). My brother was building a very hot 327. The racing dealer said that there was everything in the performance book from a warm cam for your 283 to all the internals to build a AA/fueler.

Lot of guys would put am L88 cam in their 396's.

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21 hours ago, hardtail said:

I used to have the GM performance book for big blocks that had all the part numbers and engine codes, LS6 was the highest advertised hp available in a production car at 450hp, came as an option in Chevelles or Vettes, can't remember if others got it, some think the 427 L88 or ZL1 was wilder but not advertised as more hp by GM they came in Camaros and Vettes. An electrician I used to work with had a 70's Camaro that he put a LS7 into that he said was pretty fast, difference between the 6 and 7 if I remember was full floating rods, 1 compression point higher around 12.5 to 1, open chamber heads, and a hotter cam

The 427 tall deck truck motors had a lot of differences but some guys hot rod them, peanut heads gotta go, they had 4 bolt main blocks and forged steel cranks so good base to build on

according to this article and others I have read the ZL1 was 560 hp in reality. only 2 were sold in Corvettes and 69 in Camaros, I have no idea to be honest with the ratings. https://www.roadandtrack.com/news/a42356226/one-off-corvette-zl-1-for-sale/

1970 Chevelle SS454 LS6,vs 1969 Corvette zl1 or L88 and you and I would have one heck of a street race. All those cars have less than impressive ETs in the 1/4 ( considering their potential)but that '70 Chevelle would have F70 14 bias plys on it from the factory. I don't know how you wouldn't fry those tires off the first 1/8. I wonder what they would run with some Hoosiers on them👍 

1969 Nova SS 396 L78

1970 Chevelle SS 454 LS6

1969 Corvette ZL1 or L88 427

1969 Camaro ZL1 427

It don't get any better than that, you guys can drive your trucks 😀

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7 hours ago, dale560 said:

Do any of you guys know if the 454 used in the heavy duty trucks from late 70s to mid 80s was the tall Deck like 427 was tall deck truck and lower deck auto and light truck.

The only one from an early 80’s C30 dually was not a tall deck, nor was one from An 87. I wasn’t aware that they were put in anything bigger than that. 

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