LS-7 Crate Engine

[Yellow 69 z28]

Does anyone know what years did the LS-7 crate motors run from - to? How about L-88's? Would GM have used a 14015445? Does anyone know what the GM part number would of been for either the LS-7 or L-88? Would the short blocks have been painted?

Found a brand new GM short block with pistons having a casting number "3947886 GM" stamped on the top. The block is not painted or stamped but has unusual multi-color paint markings all over on the block, crank, and rotating assembly. There is a cam present, but I have not pulled it yet to view the p/n. I also need to look at the crank p/n.

Just curious.

[68z302]

Can't tell you about your engine. but looking at it makes me drool!

[70judge]

hi I think they made the l s 7 from 1971 to 1973. my l s 7 heads had a 71 and a 72 casting numbers. my head were 990 124 cc chambered not 119 chambered also my lower end had a nitrated crank dimpeled rods and forged domed pistons. and a 4 bolt main. It had every high perf. part gm had made at that time.

[PxTx]

Are you sure you that engine is an LS7? If you look in the lower right hand corner you can see it indicating its a 4/27

[Astock]

It's a LS7.Check the casting date on the block and 990's.I bet it's around mid 80's.There should be a off road use only tag if you took it out of the crate.I bought a couple of the last L-88's in 1980 and the blocks were 289 castings 454 blocks dated 1973.

[Yellow 69 z28]

The casting looks like a 1978 but I am going to check further. There are three sets of heads, 1st set are 3946074's with "9.7.71" and "1.3.69". and 2nd are 14096188's with "F130" and "G090" and last is a set of 6272990's with "B-26-74" and "C-1-74". The 074's and the 990's are assembled and the 188's are bare. The 074's have been used but briefly. Here's the casting date on the block.

I have a feeling that this motor will rock!

My next quest would be pull the cam and check the number and I may have to check the crank.

Can somebody PM me with a esitmated value?

[Yellow 69 z28]

Here is the piston casting. Someone has said it could be a ZL-1 casting number.

[GM-26]

In 1988, I went to my local Chevrolet dealership to purchase either a LS-6 or LS-7 "crate motor". They were both available. The LS-6 was $2,800.00 and the LS-7 was $2,400.00. I chose the LS-6, due to the lower compression ratio. The LS-6 carried GM Part #366250 and had a engine suffix of "XAA" and the LS-7 was GM Part# 3965774 and had a engine suffix of "XCH". My driver's valve cover had a sticker on it that read "XAA". Hope this information helps you out.

[ZL1mike]

I have a set of std ZL1 GM pistons and the number on them are GM 3981890.

Mike

[427TJ]

Yeah, my buddy bought a crate LS-7 in 1988. The 396 in his '67 Camaro SS spun a main so he went down to the Chevy dealer in Alameda (CA) and laid down a couple grand for a new LS-7. He too had the choice of -6 or -7 as there were about 10 crate motors lined up along the wall of the service area. I was very envious. It's still in the car, 12.5 pistons and all. Nothing sounds quite as rumpy as an LS-7 at idle. The unburned gas fumes coming out the tailpipes could kill an army.