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Discussion Starter #1
Does anyone have the factory hp and Torque ratings for the LS7 454 crate engine.Also if anyone knows the Cam specs I would appeciate it.thanks
1970 SS396 Chevelle
 

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I assume your asking about the 454/425hp crate motor currently available from GM.
( I have one and love it) If so, I'd recommend you stop by your local Chevy Dealer and either buy the Performance Parts Catalog or ask them if you can just look at it. In this catalog they only have the Performance Motors and Parts but they list the spec's for each engine along with the complete Parts List

I don't have mine with me right now or I would give you the info.

I think paceparts.com has the inform on their web site also.

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Bill Taylor
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December 1999 Feature Car
www.chevelles.com/feature/december99.htm
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[This message has been edited by Bill T SS70 (edited 01-24-2000).]

[This message has been edited by Bill T SS70 (edited 01-24-2000).]
 

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If you mean the "real" LS7, I learned here that they were never assembled as a crate. But the parts are beefy as heck. If my crate 1970 L88 could do 560 hp on Sunoco 260 and headers ( so I've heard ), the LS7 had to be good for nearly 600. Just as much CR, more cam, more cubes.

Run a search and you'll find the cam specs. Listed as a "off road only mechanical". It was a bit longer duration than L88, and more lift, to be non-exact, 265 duration @0.050 and .600 lift. Guys here know, I was corrected on this subject by a local LS7 sharpie. Maybe run my user name and LS7 in the search and you'll find the specs.

Edit - Aha, yes Larry below, the sharpie..

[This message has been edited by Gene Chas (edited 01-25-2000).]
 
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The LS-7 crate motor definitely was available until its discontinuance(along with the LS-6) sometime around '90-'91. It had 12.25:1 compression and the (solid lifter) cam specs were 262/273 dur. at 0.050, with lift at .580/.620. The blocked would've been stamped XCH.
 

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The LS-7 crate motor was listed as follows:

PN 3965774, 454CID, 12.25:1 compression, 4 bolt main block, 5140 forged steel crank, w/cross-drilled mains 3963524, 4340 forged steel connecting rods with 7/16 in. bolts for pressed pins, 3963552, forged high dome pistons, racing mechanical camshaft 3959180 (same as ZL-1), open chamber cast iron heads 6260482, balancer 3963530, standard flywheel 3993827, engine suffix XCH.

Listed as 465BHP, also noted was a chevy open plenum intake. 1/16th inch compression rings. Another description in the book shows 12.5:1 compression and floating wrist pins, not pressed as described in the crate motor. So there are some conflicts in features depending on what you read.

The above is from the "How to Hot Rod BB Chevys", HP books. It was first published in the 70s.

jmw


[This message has been edited by jmw (edited 01-24-2000).]
 

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Just think they were wanting to put the LS-7 in the 70 Chevelle. Could you imagine that. I seen one at the local track run. One the had a stock LS-7 crate motor in a 70 Chevelle with 4,000rpm stall and 4.10 gears run a 11.60 in the 1/4 with a puny 850 double pumper.

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69 SS 454
69 Malibu 406
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The LS-7 was the baddest mother chevy had in there engine line-up in the 70's. Big brother to the LS-6, more compression, more cam, open chamber heads, chevy thru in everything they had at the time to make power. I think of it as the "race" version of the LS-6. My buddy & I went and purchased one in the crate around 1982, at that time $1800.00 intake to pan. Dropped it in his 70 chevelle, that thing had the nasty-est idle you would ever hear in a street car. Same parallel would be the L-88 and the L-72 427, one for racing(L-88), the other for street.
If only sunoco 260 was still available at the pump. That sound, that very ,very nasty sound. Music to my ears! Glenn

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I am no expert on the LS7 but I do have one that I took out of the crate and put in a 78 SS 4sp elky. Can you say fun
. JWM and GlenLS6 have pretty much said it all. The only thing that I can add to the above is the head casting numbers would be 188 or 990, swirl polished valves, etc. Like Glen said Chevy threw everything they had at this one. The letters XCH will be stamped in the milled pad directly behind the water pump. If it is still in the crate it will have tags stuck on it in several places with a bar code and large letters XCH. Also will have warning tags stuck on the valve covers saying for off road use only.

Have A Great Chevelle Day
Mike Crosby
 

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Discussion Starter #11
Thanks for everyones reply,
It's really getting my Juice flowin.I have a 68 396/325HP in my 70 SS right now.I just purchased an LS7 crate motor from a friend of mine.The only thing I changed was adding a full solid roller comp cam.(651 rotation,650 Lift)Roller lifters,roller rockers and stud girdles.I can't wait to bolt it up to my M-22.
 

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Mr. SS, I had a '70 Chevelle SS 454 with the LS-7 crate motor coupled to an M-22. With 295/50 BFG Radial T/A's, stock motor w/headers and 3.5" exhaust using four 2.5" turbo mufflers (over 20 years ago!), 4.10 gears in street trim (not drag radials!) ran 12.16 @ 118MPH


If you'd like a peek at this bad boy (worth the click
) try http://home.earthlink.net/~bzdel/otherHiPerf.htm
 

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When I bought my LS6 XAA code crate engine in '87 I went into the dealership wanting the LS7. Unfortunately after an exhaustive GM parts network search there were no more left in stock. I'm certainly NOT complaining about the deal I got for the LS6. $2800.00 carb-to-oil pan. I could even put together a stock lo-po 454 for that now!

Tommy
 

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The LS-7 crate motor was listed as follows:

PN 3965774, 454CID, 12.25:1 compression, 4 bolt main block, 5140 forged steel crank, w/cross-drilled mains 3963524, 4340 forged steel connecting rods with 7/16 in. bolts for pressed pins, 3963552, forged high dome pistons, racing mechanical camshaft 3959180 (same as ZL-1), open chamber cast iron heads 6260482, balancer 3963530, standard flywheel 3993827, engine suffix XCH.

Listed as 465BHP, also noted was a chevy open plenum intake. 1/16th inch compression rings. Another description in the book shows 12.5:1 compression and floating wrist pins, not pressed as described in the crate motor. So there are some conflicts in features depending on what you read.

The above is from the "How to Hot Rod BB Chevys", HP books. It was first published in the 70s.

jmw


[This message has been edited by jmw (edited 01-24-2000).]

Good info here. Definitely pressed pin. L88 had the floating pins.

I have an article where they took a LS7 right out of the crate put it on the dyno and it made 550 H/P. As stated above the rated H/P was 465

I bought my LS7 in 85 off a GM employee that had puchased it new in 77 for 3500. He took it straight to Booth& Arrons had the block T plate honed, rods SP, polished with boron bolts, custom balanced. He never assembled it. I bought for 2000 and stuffed it in my 69 El Camino. Drove it to work for a while but It was to nasty for the chassis so i pulled it and sold the truck.

Fast forward 20 years I just started a project just for this engine. I am building a 70 Malibu with the LS7 bottom end AFR heads and a F2 procharger. I cant wait to here that engine come to life again.
 

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Here is the Warning tag. Kinda hard to read though.

SPECIAL PARTS NOTICE
This part has been specially designed for Off highway application only. Since the installation of this part may either impair your vehicles emission controls performance or be ######## #### preferred Motor Vehicle Safety Standards . It should not be installed on vehicles used on #####or #### highways. Additionally such application could adversely affect the warranty coverage on such #### street or highway vehicles.

 

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Yup, that is how they come.
Pal's was in a wood crate, #774 on it, that sticker on the valve cover, Har Bal and 4-spd type flywheel. Came with the long sump Vette oil pan with trapdoor, long main studs with windage tray......
One mean Hombre
 

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The early LS6 and LS7 engines that I worked on all cam apart to blueprint. The clearances were lousy and they would blow up in short order.
 

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The early LS6 and LS7 engines that I worked on all cam apart to blueprint. The clearances were lousy and they would blow up in short order.
Funny you should say that, as I bought mine about 10 yrs. ago completely disassemble and never fired.

959 block cast June 6 '76

990 heads cast May 4/5 '76

timing cover May 27

3530 balancer

3524 5140 crank

assembly date July 21 1976.

 
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