I know this is prob posted 50 times a month. I just bought a 95 Formula with of course the LT1. I don't think the oil was changed for a long time. It was black as the paint when I got it out. I went with 10w30 Valovoline high mileage conventional. Now I have friends saying I should have used Mobil 1 synthetic even with high miles. I always heard you have to start synthetic before like 40k miles or it is too late. And there is no way of knowing what was used before, conv. or synthetic. It came with no paperwork and the dealer says it has NEVER been back for warranty or recal work since new. (they are going to do the AIR pump and steering wheel control recals for me though)
So what are everyones feelings on the oil. I am keeping this one, I really like it with the conv. top.
Bret

 

You do not have to start using synthetic oil by any certain mileage. You also do not have to slowly switch it over to synthetic by using a blend.

You may start using synthetic at any time you wish. If you want to use Mobil 1 I'd suggest 0w40, it worked perfectly in my LT1. I liked it alot better than the Mobil 1 10w30 and 15w50.

 

Get that valvoline out of your car, switch to mobile 1 synthetic or royal purple. I use 10w30 mobile 1 and couldn't be happier. I would also recommend using their filters as well.

 

i agree

 

Personally I don't think there is anything wrong with the Valvoline you have in there now. I'm just saying that if you want to switch to synthetic you don't have to worry about your mileage or slowly switching it over.

In stock or near stock applications if you run a good conventional oil and change it at 3k miles I would imagine that on tear down of the motor it would be almost identical to a motor that was run on Mobil 1. Synthetic oils really show their worth when you are doing extended drain intervals or are dealing with a very hot running motor because they don't break down as easily. Hence why conventional oils with 3k mile (relatively short) drain intervals work just fine.

Since the rebuild I have been running Mobil 1 in my Nissan just because that's what I was used to using in the Camaro. However, the other day I realized that car doesn't need that oil. I change it at 3k miles, it's stock and it's not a hot running or forced induction motor. Next oil change it's getting Castrol GTX conventional oil and it will be just fine.

 

Thanks for the input everyone. I really want to keep this one stock since it is a convert. I bought it mainly to cruise in and being in Florida, the beach is always close...
I am selling a real solid, clean Mustang 5.0 and then an old Thunderbird I have and this summer I am going to start looking for a good 01 or 02 SS that will prob get a few more mods and use it as more of a driver for out of state trips. I have a company car for work and an old police auctioned Crown Vic for a rainy weather driver. I dont like leaving my cars were I cant see them unless it is the Vic.