oil change
Thread Starter
Intermediate
Joined: May 2009
Posts: 45
Likes: 1
oil change
i want to know what oil will be best for my 79 and how many quarts will i need? i never owned a v8 so i dunno lol. also i want to change the rear diff too. i used mobil one on my last car. my 79 has 67,000 miles on it. it has been sitting for a year and i have brakes done. please help.
Team Owner
Joined: Jan 2007
Posts: 53,648
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From: Southern Cal Ca
St. Jude Donor '22
i want to know what oil will be best for my 79 and how many quarts will i need? i never owned a v8 so i dunno lol. also i want to change the rear diff too. i used mobil one on my last car. my 79 has 67,000 miles on it. it has been sitting for a year and i have brakes done. please help.
Oil is a personal preference.
Wt is also a choice, unless you need multi Vs because of weather.
I use 20/50 castrol. like the 50, want the 20.
I have had to add some STP (extra wear additive) since the
new oils are getting low on it/
Rear diffy is straight weight gear oil. 1 1/2 qts ?
Get some GM posi additive. very important
Le Mans Master
Joined: Oct 2007
Posts: 7,455
Likes: 977
From: RI, Now Franklin/Nashville TN
Mobil 1 15W-50 which is a true synthetic (Group IV), has the correct ZDDP (1,200 PPM) for flat tappet engines, has excellent low temperature flow and high temperature protection, is $5 per quart at Walmart, and requires no additives which are almost never recommended by oil manufacturers since an additive can upset the manufacturers own additive package and not needed with Mobil 1 (15W-50 only since other Mobil1's do not have 1,200 PPM ZDDP). I would stay away from most mass market oils if you do not want to use Mobil 1 15W-50. I would look at Brad Penn (conventional oil), Amsoil, Royal Purple, and maybe Castrol Edge (not sure of ZDDP level, but definitely NOT Castrol Syntech (Group III pseudo Synthetic and not enough ZDDP for Flat tappet engines). Just make sure that you know the ZDDP level of whatever you decide to use! I personally would not use a conventional oil simply because synthetics offer better low temperature and high temperature protection with uniform molecule size for little incremental cost. Will it matter in real world driving? Probably not, but real cheap insurance!
Last edited by jb78L-82; May 27, 2009 at 07:13 AM.
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i want to know what oil will be best for my 79 and how many quarts will i need? i never owned a v8 so i dunno lol. also i want to change the rear diff too. i used mobil one on my last car. my 79 has 67,000 miles on it. it has been sitting for a year and i have brakes done. please help.
I use Rotella 15W40. Your car takes 5 quarts with filter. 80/90 gear weight oil for the rear end and one 4 oz bottle of GM posi lube. Fill it til it flows out the inspection hole. Then go do some figure eights to work the lube into the clutches.
Last edited by capevettes; May 27, 2009 at 09:27 AM.
Drifting
Joined: Jan 2006
Posts: 1,832
Likes: 38
From: Cedar,BC
I don't believe about 90% of the oil company marketing 
.Its more important to change it on a regular basis,if you have some small leaks stay away from the synthetics,that stuff is slippery.
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From: King George VA
I recommend the AMSOIL SAE Synthetic Premium Protection 10w40 (product code AMOQT). This oil has higher ZDDP (phosphorus on the order of 1275 ppm, and zinc on the order of 1365 ppm) than due the current API CJ-4 crop of diesel oils such as the Shell Rotella T 15w40 mentioned above, and it is actually designed for automotive use, not diesel use. I used this oil in my 02 Z06 for a few years on the track with good results before switching to AMSOIL's new racing oils. 
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