[Guest]

I am considering buying a 454 LS-7 Crate motor from this guy. The part # on the valve cover is 3965775 and there is a date also printed there of 2/23/73. He claims that he bought it new from a local chev dealer. The problem that I have is that this motor does not have aluminum heads in it. He swears it has never been touched. He also says that there is 12.25:1 compression and that it has a radical solid lifter cam. That info checks out. (Almost) From what I have read, the LS-7 was the same as an L-88 but with more horsepower. Can anyone tell me for sure (maybe from this part number) what this motor is and what it is worth? Or, at least, exactly what the specs are on an LS-7 Crate motor, including the true horsepower ratings. Thanks so much for all the great info! PS I am using my wife's email acct until I get mine up and running. Sorry about the confusion.
Steve Lorello

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sL

 

[DJM]

Steve, I have the book "Chevrolet by the Numbers 1970-75", but it doesn't list valve cover numbers. There are listings for intake manifolds, cylinder heads, and engine block identifications among others. I checked those sections, but the closest I could come to the number was 3965577 on the intake manifold id. Do you have any of these?

 

[DZAUTO]

Steve,
The last time this subject came up I asked a very dear (and wealthy) friend to look at 2 LS-7 crate motors that he has. Both have cast iron heads. The LS-7 was prepared and scheduled to be an optional engine for the 70 Vette, it was even included in ALL the sales/dealer literature. But at the very last minute it was canceled because of some failure to meet some kind of emissions requirement. You are right about the LS-7 being similar to the L-88. In the Corvette, it would have basically been a stroked L-88 (a 454 is a stroked 427). In the Corvette it would have had aluminum heads and all the good killer stuff. When it was released as a crate motor it got cast iron heads. I don't know why and I can't find anyone who can tell me. So what happened to all those aluminum heads that were scheduled to be installed in LS-7 Corvettes? Do you suppose someone took them out the back door after work and put them in the trunk of their car? I don't know that LS-7 figures have ever been released from Chev. They were probably a little higher than a 2bl 350 I bet. Now the question is, should you buy one. No doubt it would be a strong engine, but with all the parts on the market to rebuild a 454 today, I'm sure you could build one as strong or stronger than a crate LS-7. This is a factor I would consider before buying one. To me, the engine would not have any special value as an LS-7.

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[plain 69]

The cam shaft was a little more lift and a little more duration for the LS-7 than the
L-88. It had the ZL-1 cam installed with .600
lift on exaust. While the L-88 was somewhere around 560. The crate motors came with cast iron heads as said.

 

[MikeEC]

Steve,
The HP rating of the LS7 was 465. Like other High perfs of the era this was under rated and reports say that the LS7 would dyno at around 550 HP. I have never seen torque ratings published. The LS7 has the ZL1 cam, swirl polished valves, open chamber heads, etc. 12.25 compression. I have all tags and such from a crate LS7 but unfortunately they are misplaced right now. One sure way to identify this as a LS7 is to look on the smalled milled area in the center of the block right behind the water pump. You should find the letters XCH stamped there. When I find my stuff I will send you more info, part numbers, etc. Do you have tags on the valve covers that say this engine is for off road use only? This engine is pretty radical but will idle fine at 900 rpm but the power brakes like 1000 rpm idle. This engine likes a lot of timing and needs more octane than you can buy at the pump. I run a mix of about 2.5 gal of CAM2 to 14 gal of 94 octane Sunoco. If I go racing I will plus up the CAM2 a lot. Enjoy. Do a search on the tech pages for LS7, I think you will find all you need to be sure. Enjoy.

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ACES #02334
Mike Crosby

 

[jmw]

Here is a part number and description I found for the crate LS-7. P/N 3965774 (off by one, who knows why).

454 CID, LS7. 12.25:1 compression, 4 bolt main iron block, 5140 forged steel crank w/cross-drilled mains (3963524), 4340 forged-steel connecting rods w/7/16 bolts for pressed pins (3963552), forged high-dome pistons, racing mechanical camshaft (3949180), open chamber cast-iron cylinder heads (6260482), balancer (3963530), standard flywheel (3993827), does not include water pump or intake manifold. Engine suffix XCH.

From the part numbers, the heads are 2.19/1.88 inch valves, 118 cc. Cam is .560 intake and .600 exhaust lift, 322/334 degree duration, same as the ZL-1 cam.

From "How to Hot Rod BB Chevys", H.P. Books.

John Walker

[This message has been edited by jmw (edited 06-03-99).]

 

[Tom Lasater]

No one has addressed the value, yet...I've seen them around the Detroit area for $3500 although the asking price is in the 4k area. Jim Pace in Ohio is selling 502/502 long blocks for less than GM dealer cost, still close to 6K but more streetable. Buy the LS7, when you fire it up your heart will spank your ribs BIG TIME! I bought and sold a LS7 and just two weeks ago bought a LS6 in the box so they're still around. Have Fun!

 

[Alex_K]

Steve..The replies to your question should cover most ground. Here is my 2 cents from past experience. In 1977 I bought a Baldwin Motion 74 Firebird (yes I wished it was a Chevelle) from a fellow here in NY.
The car had an LS7, turbo 400, and 488 12 bolt. I used to drive around with Sunoco 260 and Moroso additive. To make a long story short, I took the car to the track (on a flat bed) and with 10.5 X 28.5 tires ran a best of 11:27 after 5 passes.
Things are different now. If it's a drag car go for it. If you want to "drive" it. It will be a real challenge. I think 9.5:1 comp. and 323-373 gears are what makes cruising fun now. I don't know how good the new 454 and 502 engines are, but if they hold up they are a good buy...and desighned for our times. The LS7 was a "real stock racing engine"...good luck

 

[elcamino]

On the subject of aluminum heads on the early 60 and 70 engines. I once read some information that stated that Chevy had many problems and high failure rates on aluminum heads and went back to cast iron to cut there warranty claims. I remember reading this some years ago.