69 350 "with special high performance"

[Keith M.]

When I see this in the parts catalog, which engine is it referring to? I always understood it to be the L46 350/350, no?

[Duke W.]

Re: 69 350 "with special high performance"

The '69-'70 L-46 350 HP engine is actually referred to in the P & A catalogs as High Performance as is the '73-78 L-82, which is essentially a lower compression (9:1) version of the L-46.

The '70-'72 LT-1 engine are referred to as Special High Performance.

Back in 1965 there were two SHP engines. The 350 HP L-79 was referred to as Special High Performance w/hydraulic lifters and the 365 HP L-76 as Special High Performance w/mechanical lifters.

Sometime the P & A catalogs are a bit esoteric regarding part applications.

The above is all derived from the 9/77 version of the P & A catalog, Group 0.519, Camshaft.

Duke

[Joe L.]

Re: 69 350 "with special high performance"

When I see this in the parts catalog, which engine is it referring to? I always understood it to be the L46 350/350, no?

Keith------


As far as the P&A catalogs go for the 1969 model year, high performance 350 (H/Per)350 refers to the L-46. Special high performance (SpHPer) 350 refers the LT-1 which was scheduled for 1969 but never released. Apparently, the information got into the parts manual before the engine was dropped. This sometimes happens and there are other examples of it, notably the LS-7 for 1970.

[Keith M.]

Re: 69 350 "with special high performance"

Keith------


As far as the P&A catalogs go for the 1969 model year, high performance 350 (H/Per)350 refers to the L-46. Special high performance (SpHPer) 350 refers the LT-1 which was scheduled for 1969 but never released. Apparently, the information got into the parts manual before the engine was dropped. This sometimes happens and there are other examples of it, notably the LS-7 for 1970.

Thanks Joe. Was looking to verify plugs for L46 original as gm#5569993 which I know now are indeed correct.

[Tom R.]

Re: 69 350 "with special high performance"

Joe
Are the cams the same; L46 and L82?

[Duke W.]

Re: 69 350 "with special high performance"

Yes, the cam-pin assembly that was sold over the counter is 3896962. This cam has two degrees more .050" lifter rise duration than the L-79 (3863151 cam and the same LSA. The biggest difference it that the IPOML is retarded four degrees relative to the L-79 to 114 deg. ATDC.

I recommend it to replace the L-79 cam on 327s, but install it 4 degrees advanced to bring the IPOML back to 110 degrees ATDC, same as the L-79 cam. The reason is that it has better lobe dynamics.

OP - I recommend you install AC R45 plugs. AC heat range 5, one notch hotter than the OE heat range 4, is best for all vintage SB and BB engines in normal road use by preventing excess deposit build up that can cause fouling.

Duke

[E S.]

Re: 69 350 "with special high performance"

when I ordered my 69, I checked LT1 (370 HP) on the Dealer's Order Sheet (still have the car)-I had always been a solid lifter small block guy,so I was disappointed when I had to RE ORDER,so chose L46-
In retrospect-I guess I should have waited and ordered a 70 LT1- Or at least a Big Block?

[Joe L.]

Re: 69 350 "with special high performance"

Joe
Are the cams the same; L46 and L82?

Tom-----

As Duke mentions, yes. And, the GM #3896962 camshaft is still available from GM under its original part number more than 55 years after its original release. It is still used in some GM gen I small block crate engine assemblies. Must be a pretty special piece to have survived that long, especially into the era of hydraulic roller type camshafts.

[Tom R.]

Re: 69 350 "with special high performance"

when I ordered my 69, I checked LT1 (370 HP) on the Dealer's Order Sheet (still have the car)-I had always been a solid lifter small block guy,so I was disappointed when I had to RE ORDER,so chose L46-
In retrospect-I guess I should have waited and ordered a 70 LT1- Or at least a Big Block?

A wise view to stick with smallblocks...my view. I always found them clunky, hot and cabin occupants...sweaty! I'm sure BB enthusiasts will "cancel" me given talking bad about BBs is not PC. LOL I hope they can handle the friendly comradery.

My 67 Chevy II SS beat 396s routinely. I remember one 427 Chevelle...black on black. I was running a 456 rearend with 8 inch Mickey Thompsons and pulled a hole shot that left it way behind. But...he must have had a big gear and caught me before we hit the finish line. Lost some $ that night. Took place on Mannheim, paralleling a O-Hare field runway. Later that runway was used for Boeing 747s. The Chicago would know the road...one of them may have been there that night. I had a t-shirt that read "Small blocks forever" and featured a Chevy II caricature chomping down on a 396 pumpkin Camaro. One of the guys in our "car guy" crowd hated that t-shirt. He could never win.

[Keith M.]

Re: 69 350 "with special high performance"

A wise view to stick with smallblocks...my view. I always found them clunky, hot and cabin occupants...sweaty! I'm sure BB enthusiasts will "cancel" me given talking bad about BBs is not PC. LOL I hope they can handle the friendly comradery.

My 67 Chevy II SS beat 396s routinely. I remember one 427 Chevelle...black on black. I was running a 456 rearend with 8 inch Mickey Thompsons and pulled a hole shot that left it way behind. But...he must have had a big gear and caught me before we hit the finish line. Lost some $ that night. Took place on Mannheim, paralleling a O-Hare field runway. Later that runway was used for Boeing 747s. The Chicago would know the road...one of them may have been there that night. I had a t-shirt that read "Small blocks forever" and featured a Chevy II caricature chomping down on a 396 pumpkin Camaro. One of the guys in our "car guy" crowd hated that t-shirt. He could never win.

Why stick with small blocks if you find them clunky and hot?

[Keith M.]

Re: 69 350 "with special high performance"

when I ordered my 69, I checked LT1 (370 HP) on the Dealer's Order Sheet (still have the car)-I had always been a solid lifter small block guy,so I was disappointed when I had to RE ORDER,so chose L46-
In retrospect-I guess I should have waited and ordered a 70 LT1- Or at least a Big Block?

So if you got the 69 LT1 you still have why did you have to reorder?

[Tom R.]

Re: 69 350 "with special high performance"

Why stick with small blocks if you find them clunky and hot?

I failed to proof that post...big blocks are!