Ls7

[Joe L.]

Re: Ls7

Block casting#3963512,Machine stamp CE165673.Boy,you guys sure have a lot of old info,great education for me,thanks again for the replies.

Tag-----


The GM #3963512 was a 4.25" bore big block used in PRODUCTION for 1969 427's and 1970 454's. However, it might have been used for SERVICE after that time. Can you discern the casting date? This should be located on the bellhousing flange on the right (passenger) side, approximately opposite from where you found the 3963512 casting number.

Does this engine have aluminum or cast iron heads? It would be interesting to know the casting number and date if you could remove one of the valve covers to see it. Also, have you been able to run it without significant "pinging" or pre-ignition on pump gasoline?

[Joe L.]

Re: Ls7

Joe,

I think I have some GM info on the 3965774 engine assembly that was dated at least two or three years earlier than 1975. The first info released to dealers came in a multi page flyer called "Hotline". The first one that I remember for the LS7 was titled "Horsepower To Burn", and it described the assembly and it's components.

In 1971 or 72, I was told that when GM nixed the LS7 option for production cars, the existing engines were stored in a separate warehouse somewhere. Eventually, they were to be sold through P&A at a very reasonable price until all were gone. For some reason, GM decided to continue producing the LS7 engine for over the counter (so to speak) sales.

The earliest information I had about the new LS7 was in late 1970. A group of high perf/HD parts in that 3965XXX part number range were released at the same time.

Add On: Found one dated 25 July 73. It lists absolutely every part and part number used to assemble an LS7 engine including the cyl head and clutch housing dowel pins, block coolant and oil gallery plugs, oil pan bolts etc etc. Many items that were never listed in the parts book.
I know I have earlier Hotline sheets and other GM info that describe the LS7. I'll look.

Michael------


1973 could have been the release date for the 3965774. It was not available as of February, 1972 but was available as of July, 1976. So, the release date had to be sometime between those points.

A partial engine assembly (short block) was available by April, 1970, if not before that time, under GM #3981824. A fitted block was also available at that time under GM #3981812.

The GM #3946072 cylinder heads were, of course, available well prior to this time since they were also used for 1969 L-88, L-89 and ZL-1.

The LS-7 crankshaft, GM #3963524, was available by April 1, 1970 or prior. The camshaft, GM #3959180, was the same as 1969 ZL-1.

The intake manifold, uniquely applicable to 1970 LS-7, was also available under GM #3977610. This manifold may have used casting #3963647.

So, if nothing else, all the parts necessary to build an LS-7 were definitely manufactured and available.

[Joe L.]

Re: Ls7

The crate engines destined to be sold by your local dealer had the typical machine codes stamped on them. Bare cylinder cases did not have anything stamped on them. I have blank 351 and 512 blocks with nothing stamped on them. I am unsure about the fitted blocks as to whether they were blank or stamped.

Dick-----


My experience has been that anything other than a complete engine assembly had no stampings on the stamp pad. This included partial engines (short blocks), fitted blocks, and bare blocks. It's possible that some or all partial engines available through the "CE" warranty replacement program did have "CE" stampings, though.

I do not see how anything other than a complete engine could have had a suffix code stamped on the pad. The suffix codes denoted the configuration of a complete engine assembly and were often specific right down to some rather "trivial" components of the assembly. With anything less than a complete engine, there would be no way to know what the configuration of the "to-be-completed" engine would be. Of course, there could have been SPECIFIC suffix codes assigned to just what the particular partial engine or fitted block contained, but I know of no such codes ever used.

[Joe L.]

Re: Ls7

There was also a "fitted case" I believe that was the cylinder case and pistons, but nothing else. Yes, if certainly can get confusing.

Terry------


There were several designations used by GM to describe engines or major components thereof:

ENGINE ASSEMBLY (PRODUCTION)-----this describes a complete, FULLY DRESSED, engine assembly. These usually include everything included with an engine installed in a PRODUCTION vehicle. When available, they are available ONLY during the model year to which they are applicable. These are virtually never shown in a P&A Catalog.

ENGINE ASSEMBLY (SERVICE)---this described a complete engine assembly including the cylinder block, all internal cylinder block parts, and complete cylinder heads. Other components varied as to their inclusion in the assembly (e.g. intake manifold, exhaust manifolds, oil pan, timing cover, distributor, etc.). Engine assemblies were usually not carried in the P&A Catalogs.

ENGINE ASSEMBLY, PARTIAL----this is a complete block assembly including all internal parts, except valve lifters. Usually not included are parts like timing cover and oil pan.

FITTED BLOCK ASSEMBLY----includes block, pistons, pins, and engine bearings.

BARE BLOCK------just the block with main caps and bolts. Nothing else.

[John N.]

Re: Ls7

The LS-7 as sold in the 84-90 time span did not include a intake manifold.
Regards

[Joe L.]

Re: Ls7

The LS-7 as sold in the 84-90 time span did not include a intake manifold.
Regards

John------

As far as I can tell, none of the engines sold under GM #3965774 included either an intake manifold or a waterpump.

[Michael H.]

Re: Ls7

John------

As far as I can tell, none of the engines sold under GM #3965774 included either an intake manifold or a waterpump.

That's correct. I'll try to scan/post the parts list that included EVERYTHING that came with an LS-7 engine assy. That included several number for misc parts that I've never seen in any other GM parts book.

[Tag W.]

Re: Ls7

Joe,I have not physically seen the car yet,the numbers were given to me by the owner.I'm not sure when I will get to inspect the car.

[Joe L.]

Re: Ls7

That's correct. I'll try to scan/post the parts list that included EVERYTHING that came with an LS-7 engine assy. That included several number for misc parts that I've never seen in any other GM parts book.

Michael-----


Here's the parts:

3981824----ENGINE ASSEMBLY, PARTIAL

3981812----ENGINE ASSEMBLY, FITTED BLOCK

3946072----HEAD, CYLINDER

3963524----CRANKSHAFT

3977610----INTAKE MANIFOLD

3969865----GASKET, CYLINDER HEAD

3969815----VALVE, INTAKE

3946077----VALVE, EXHAUST

3916164----SPRING, VALVE

3879613----CAP, VALVE SPRING

3959182----ARM, ROCKER

3942415----PUSHROD, EXHAUST

3942416----PUSHROD, EXHAUST

3959180----CAMSHAFT

3969804----CONNECTING ROD

3976014----PISTON, STANDARD

3879912----RING UNIT, PISTON

3963530----BALANCER

3965357----FLYWHEEL

3886066----CLUTCH PRESSURE PLATE ASSEMBLY

3886059----CLUTCH DISC

1108381----STARTER

1111465----DISTRIBUTOR

[Michael H.]

Re: Ls7

Michael-----


Here's the parts:

The five page "parts list" that is included in the five pages of Hotline is MUCH more complete. It also includes part numbers for odd things like;

Pin, flywheel dowel
Key, torsional damper
Bolt, torsional damper
L/washer, torsional damper
Cyl and case, (bare block)
Cap, c/shaft main
Cap, c/shaft main
Bolt, c/shaft main
Stud, c/shaft main
Plug, oil pressure
Plug, oil gallory
Plug, water
Plug, water jacket
Plug, cyl & case-oil gallery
Plug, oil pressure guage holePin, oil pump
Pin, cyl head dowel
Pin, clutch housing
Pin, c/case front cover dowel
Screw & LW assy, front end cover
Plug, cyl head water jacket hole
Bolt, oil pump cover
Washer, oil pump cover
Pin, dist to oil pump shaft sleeve
Screw, oil pan
L/washer, oil pan
Nut, oil pan baffle
Washer, oil pan baffle
Bolt, camshaft sprocket
Bolt, valve rocker cover
Plug, water temp hole

In addition to all of the internal parts that are listed in the parts book. Most of the above items are not. This is the most complete parts list I've seen for an engine assembly.
I didn't include part numbers as most/all are likely no longer available from GM.
A few of the part numbers are different than those that you posted. I suppose that's because this was a later printing of the parts list. (1973)

[Clem Z.]

Re: Ls7

Michael-----


Here's the parts:

3981824----ENGINE ASSEMBLY, PARTIAL

3981812----ENGINE ASSEMBLY, FITTED BLOCK

3946072----HEAD, CYLINDER

3963524----CRANKSHAFT

3977610----INTAKE MANIFOLD

3969865----GASKET, CYLINDER HEAD

3969815----VALVE, INTAKE

3946077----VALVE, EXHAUST

3916164----SPRING, VALVE

3879613----CAP, VALVE SPRING

3959182----ARM, ROCKER

3942415----PUSHROD, EXHAUST

3942416----PUSHROD, EXHAUST

3959180----CAMSHAFT

3969804----CONNECTING ROD

3976014----PISTON, STANDARD

3879912----RING UNIT, PISTON

3963530----BALANCER

3965357----FLYWHEEL

3886066----CLUTCH PRESSURE PLATE ASSEMBLY

3886059----CLUTCH DISC

1108381----STARTER

1111465----DISTRIBUTOR

the LS-7 sold over the counter was 3965774 and it had cast iron open chamber heads.

[Michael H.]

Re: Ls7

the LS-7 sold over the counter was 3965774 and it had cast iron open chamber heads.

Yup, and they were part number 3994025 in 1973. The original number in 1970 was different though but it too was a cast iron head.

[Clem Z.]

Re: Ls7

Yup, and they were part number 3994025 in 1973. The original number in 1970 was different though but it too was a cast iron head.

they were used by a lot of dirt track racers just by changing the cam and drag racers used the #180 cam

[Patrick B.]

Re: Ls7

Fitted blocks were stamped with a CE and sequence number on the pad as were short blocks. Bare blocks had an unstamped pad but had the date portion of the Tonowanda stamp (T0924 for example) stamped on the oil pan mounting surface of the block near the oil filter opening. I do not think complete crate engines used a CE designation. They would have used the whole Tonowanda stamp on the pad with a code for horsepower. They would have simply been missing the VIN derivative. The LS-7 engine in question appears to have been built from an LS-7 short block with the other parts obtained separately by the dealer and assembled by the dealer.

[Michael H.]

Re: Ls7

Fitted blocks were stamped with a CE and sequence number on the pad as were short blocks. Bare blocks had an unstamped pad .

Patrick,

I think both bare and fitted blocks would have a blank pad. Partial/short blocks would be stamped CExxxxx though. At leas this is the way it was in the late 60's to at least the mid 70's.