Timing and oil for 1970 LT1

[Adam F.]

What is the correct timing setting for a 1970 LT1 350/370HP?

I am currently using Valvoline 10/40 oil and wanted to know if there is a better recommendation for my 1970 LT1?
Many thanks for any help provided.
Adam

[Adam F.]

Re: Timing and oil for 1970 LT1

Ignore question about timing as I saw what I needed on another post.
Thanks

[Duke W.]

Re: Timing and oil for 1970 LT1

Do you read The Corvette Restorer magazine?

In addition to the recommended initial timing being is the service manual, and possibly on the "tuneup sticker" in the engine compartment, if it's still there, it is in the AMA specs that you can download from the GM Heritage site, but keep in mind that the recommended initial timing - in fact the whole spark advance map - is set up for emissions, not performance and fuel economy.

Duke

[Joseph K.]

Re: Timing and oil for 1970 LT1

Do you read The Corvette Restorer magazine?

In addition to the recommended initial timing being is the service manual, and possibly on the "tuneup sticker" in the engine compartment, if it's still there, it is in the AMA specs that you can download from the GM Heritage site, but keep in mind that the recommended initial timing - in fact the whole spark advance map - is set up for emissions, not performance and fuel economy.

Duke

Duke,

(In accordance with the motors book and the sticker on the fire wall) I have set my 69 350/350 at 8 Degrees BTDC with the vacuum hose plugged. Is that the best setting for performance. Joe

[Joe R.]

Re: Timing and oil for 1970 LT1

What is the correct timing setting for a 1970 LT1 350/370HP?

I am currently using Valvoline 10/40 oil and wanted to know if there is a better recommendation for my 1970 LT1?
Many thanks for any help provided.
Adam

Adam,

What API category is the Valvoline? I'm guessing it doesn't have enough ZDDP in it to keep from flattening your cam. You should read Duke's engine oil article in the restorer or online carefully. You want CJ-4 oil. Shell Rotella is one example. It's available at Wally-Mart and elsewhere. I'll post a link to Duke's article if I can figure out how to do that from my phone.

Joe

[Joe R.]

Re: Timing and oil for 1970 LT1

Adam,

What API category is the Valvoline? I'm guessing it doesn't have enough ZDDP in it to keep from flattening your cam. You should read Duke's engine oil article in the restorer or online carefully. You want CJ-4 oil. Shell Rotella is one example. It's available at Wally-Mart and elsewhere. I'll post a link to Duke's article if I can figure out how to do that from my phone.

Joe

Adam,

Here ya go (it starts on page 3):

http://www.stlouisncrs.org/news_files/St_Louis_NCRS_Chapter_July_2011.pdf

Joe

[Duke W.]

Re: Timing and oil for 1970 LT1

Duke,

(In accordance with the motors book and the sticker on the fire wall) I have set my 69 350/350 at 8 Degrees BTDC with the vacuum hose plugged. Is that the best setting for performance. Joe

No. Your spark advance map is set up for emissions. A performance fuel/economy map should look more like the '64-'65 365/375 HP engines, which would require a new VAC, conversion to full time vacuum advance, bypassing TCS (if equipped), lighter centrifugal springs, and possibly modification of the distributor to provide a different amount of centrifugal advance.

Download the '65 AMA specs and compare the SHP/FI spark advance map to yours.

Post both here is you want to discuss further, and keep in mind that if your car requires field emission testing, modifiying the spark advance map may result in test failure.

Duke

[Joseph K.]

Re: Timing and oil for 1970 LT1

No. Your spark advance map is set up for emissions. A performance fuel/economy map should look more like the '64-'65 365/375 HP engines, which would require a new VAC, conversion to full time vacuum advance, bypassing TCS (if equipped), lighter centrifugal springs, and possibly modification of the distributor to provide a different amount of centrifugal advance.

Download the '65 AMA specs and compare the SHP/FI spark advance map to yours.

Post both here is you want to discuss further, and keep in mind that if your car requires field emission testing, modifiying the spark advance map may result in test failure.

Duke

thanks Duke