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

[NorCam]

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.

[luzl78]

Love those piston domes!

[scuncio]

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.

[NorCam]

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.

[dustinm]

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 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 and with a rowdy engine like that even with less compression, 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

[ZAPPER68]

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...

[dykstra]

Way cool!!! Congrats on a killer score!

[Lynn]

Agree 100% with dustinm.

[BCreekDave]

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?

[L_e_e]

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.