Deep Pulley Question for you '67 L78 Owners

[Chevelle SS 396 L78]

I've been researching parts for a build of an original '67 L78 block for my eventual clone build of original 1967 Chevelle SS 396 L78. It's been interesting researching the '67 L78 design and the appropriate part numbers and date codes for date correct engine build.


I actually have three questions for those of you who have or have owned L78 1967 Camaros:


1. Did your stock alternator from the factory (37 amp I assume) come with a deep groove pulley on it?


2. If your engine is still stock, whether original or rebuilt to stock specs, how does it perform on premium pump gas (91 to 93 octane)?


3. Any recommendations for an engine builder in central/sough central PA who knows the L78 engine thoroughly?


All input much appreciated,


John (in PA)

[DougA]

Originally Posted by Chevelle SS 396 L78

I've been researching parts for a build of an original '67 L78 block for my eventual clone build of original 1967 Chevelle SS 396 L78. It's been interesting researching the '67 L78 design and the appropriate part numbers and date codes for date correct engine build.


I actually have three questions for those of you who have or have owned L78 1967 Camaros:


1. Did your stock alternator from the factory (37 amp I assume) come with a deep groove pulley on it?


2. If your engine is still stock, whether original or rebuilt to stock specs, how does it perform on premium pump gas (91 to 93 octane)?


3. Any recommendations for an engine builder in central/sough central PA who knows the L78 engine thoroughly?


All input much appreciated,


John (in PA)

If you're looking for a quality machine shop, call Jim Bowen Racing Engines, Glen Rock, Pa.
Stellar reputation, knows BBC's well. Did my 427 in my drag Elky, been running strong for years. Know lots of people that are very happy with what he's done for them.

[Chevelle SS 396 L78]

Thanks Doug!

[plumL78]

They all had a deep groove pulley with #3844100AK on them except for the calif. smog cars. I believe some of them have been found to have a double groove alt pulley. they also could have been a 42 amp alt. when heavy duty battery was ordered

[Steve Shauger]

Here's some component #'s on my car.

[Chevelle SS 396 L78]

Thanks for the info so far guys! I've attached a pic of my '67 Chevelle L78 engine when practically new (you can tell the firewall is nice and fresh!). Note the alternator.....this appears to be a standard pulley arrangement. Either some L78's came out of the KC plant with non deep pulley alternators, or someone on the engine assembly line in Tonawanda screwed up!

I had problems with my power steering belt going off under hard acceleration [i.e. drag racing! :-)], and I've often wondered if the power steering pump also didn't have a deep pulley. This will always be a mystery to me. The crank pulley no doubt was the 3 groove deep pulley arrangement (the car had no smog & no A/C of course).

I thought I'd ask this question on this forum, since there were probably more L78 Camaros in '67 than Chevelles. Just looking for answers.

I am building an L78 engine to as close as my original engine's specs as I can get.

Thanks for the input,

John

[1967 4K]

Far fewer 67 L78 Chevelles than Camaros. I think the Chevelle # is in the 600’s, not certain.

[plumL78]

Jon Mello had a 67 Z survivor with around 11k miles that had a standard alt pulley on it with a heavy duty alt. He thinks they didnt have a heavy duty alt. with a deep groove pulley at the time the car was built so they just used what they had. Do you recall your orig chevelle having a heavy duty alt. option ?

[Chevelle SS 396 L78]

Originally Posted by plumL78

Jon Mello had a 67 Z survivor with around 11k miles that had a standard alt pulley on it with a heavy duty alt. He thinks they didnt have a heavy duty alt. with a deep groove pulley at the time the car was built so they just used what they had. Do you recall your orig chevelle having a heavy duty alt. option ?

No, I don’t believe it did or it would have been listed as an option on my order form & the window sticker, which I have. That’s interesting though! After all these years finding this out intrigues me. Times were much different back then & I suppose mistakes happened on the car assembly line!

[tjs44]

this is a older thread.I bought one of the GM 493243 pulleys and a std belt sits deep in it.Tom https://www.yenko.net/forum/showthread.php?t=122242