NOS 454 LS7 #3965774 w/ GM Ink Stamps & Paint Marks
 

Bought this LS7 motor yesterday and thought to share some pics of the paint marks and ink stamps on the NOS block. It's GM part #3965774 which is the over the counter long block 454 LS7 motor. This one was squirreled away in a private collection of engines and parts and I was excited to score this one.

Haven't decided exactly what I'll do with it just yet but leaning towards another Day 2 build with this serving as the foundation. Maybe clear coat the block and heads to preserve the ink stamps and markings. It came with the NOS 990 heads, tin work, flywheel and balancer, and the seller threw in a Tarantula TM-2R intake and 4296 Holley #3955205 Carburetor to go along with it.

It should make some decent power. :naughty:

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Love those piston domes!

Nice short block. You planning to run those pistons as-is? I’ve thought hard about doing a high compression purpose built 427 but know it would be tethered to c16 or similar race fuel.

Could mill down the pistons but that means rebalancing the assembly after it was just taken down, clearanced and reassembled.

Those domes make 12.25:1 compression with the 990 heads so I'm going to explore thicker head gaskets to see what compression can be bled off. Maybe that and keeping the timing a few points lower with some race fuel mixed in will fit the bill. I am also at 3600' elevation so that does allow for a decent compression write off as I understand it. This would be run strictly as a Saturday night special when I want to go out and rip a few gears around town.

Bleeding off compression with headgaskets will not produce the results you are seeking. It will overheat, be down greatly on power vs an engine built with the correct "quench" at the same lower compression. I think i would just make buddies with the local airport manager to source a steady supply of avgas. I mean how much do you plan to drive it anyway? I average less than a thousand a year with a more streetable engine and with a rowdy engine like that, even lowering the compression to a reasonable number, it would be even less.


It sure is a super cool find !!! Even if you put it under a glass table to stare at it would still be cool

Interesting...today I installed the crank and pistons in my LS7 after a refresh. I'll have it assembled by the end of the week and it's going back in my '69 Camaro.

My Camaro is a 45K mile original, Fathom Green, medium green interior, powerglide, 10" convertor with 5.13's. Perfect for going for an icecream this summer...

Way cool!!! Congrats on a killer score!

Agree 100% with dustinm.

Its interesting that the head surfaces are milled instead of broached like the oil pan and mains are. GM must have preferred a secondary cleanup cut on this engine. I wonder if it is machined to a zero deck height?

Great piece, I would 100% plan on disassembling and going through it, I've seen plenty of those LS-7 (XCH) crate motors that were poorly machined and assembled.

Yes Dustin...I can always run some Av gas in it. There's a small regional airport nearby where a friend stores a couple of his small planes. Haven't checked the cost of aviation fuel out in many years but they have 100 octane available as an option. As you said...it'll hardly be driven enough to think twice about that...and I've never been known to complain about fuel costs either.

Lee, I bought the engine from a friend who owns a local machine shop. He got it from his buddies estate sale when his friend passed a while back and was planning to keep it for himself. He took the engine to his shop and had his boys take it down, go through the entire engine, clearance the assembly and once he was good with everything, it was reassembled and stored as seen above. He might have zero decked the block but I failed to ask him about that as we were doing a couple deals and it was getting late the other evening.

I'm heading over to his shop to look at some other parts that I bought and will have a look at the heads when I'm there. He also picked up a #260 @ .050 solid roller camshaft he was going to run in this motor and that comes with it. His engine builder will be assembling the heads in his shop and it will all be buttoned up in time for me to pick it up in a couple weeks from now.

When spring time rolls around, I'll get it loaded onto the run stand and fire it up for a few run sessions and check it for leaks. Maybe by that time...I'll decide what I am going to load it into. I have a couple options for this one. I'll add some more pics later in the week.

Can't wait to hear this bad mofo!!:worship:

Went over to Rod's shop today to check out the heads and the other parts bought with the LS7. Heads had paint marks on them as well but were cleaned up and surfaced just to get the haze off them from sitting around for 40+ years. They'll get bigger springs to match the new roller cam and will soon be going together with some vintage NOS Crane 1.7 rockers. Going to have to see what covers I can fit around the rockers. Perhaps a set of Ansen's with some spacers to get the look I want.

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The cam for this motor is a custom ground Comp solid roller based off an 11-693-8 core with 262 duration @ .050 with .652 lift on a 110 LSA. It came with Comp roller lifters and 1.7 Ultra-Gold rockers. It'll be topped with this Torker II single plane and I might also use this 850 Holley on it but haven't agreed on a value yet for the core. It's 3955205 dated 944 and is probably worth more to someone with a 427 than it is to me but we have to agree on a value before I send it off to be rebuilt. Nice nostalgia piece, but may just choose to run the newer Edelbrock VRS-4150 if the cost to restore this one gets too silly.

Anyone have a realistic value on a rebuildable 4296 core for an L88 motor?

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Finally...I'm debating putting this motor into my Black and White 55 Post. I was nearly done buttoning it up with a freshly built SBC, but can also use that motor for another project I have waiting on the sideline. I'd have to modify a few things to fit the big block into the 55 but it's doable...

The good thing is that he pretty much gave me a set of Hooker Super Comp Headers to use with the motor in the 55 and they have never been run.

Debating on this one, but also know of a 70 Nova 396 car w/o the motor. :dunno:

https://i.ibb.co/FbNSmRjx/IMG-2409.jpg

Does a BBC drop right into a '55, engine needs to be set forward a little bit?

Takes a little work to do it right. First, you need a good quality engine mount (3/4" forward position) and if running tall valve covers, you end up needing to notch the firewall with a pocket kit in to provide the needed clearance at the back. Next you need a good set of headers to squeeze in, and that usually means some mods with your steering box assembly. Some run a rack and pinion, others build custom headers and fit them around a 605 steering box. Finally, you need a really good radiator to keep them running cool.

I've done it before, and now it looks like I'm about to do it again. :naughty:

https://i.ibb.co/67KvS3j5/Double-18.jpg