I just completely rebuilt my 94 Z and I want to start it up right. I wasnt sure weather to go synthetic or not. I'm probably gonna use a straight 40 weight considering I live in south florida and its never cold here. What is your opinion????
Thanks

 

First of all, don't break in your motor on synthetic oil. Bad idea. I would say after the first or second oil change, switch to synthetic I use Shell 10-50 or 40 don't remember exactly, it's been a while since I changed it.

 

Use a basic oil for the first 1000 miles or so I would go second oil change, basic oils are good these days absolutely no harm in using them long term so don't rush the synthetic.

I would not bother to use a straight weight oil.

 

Good quality 10W-40 Dino oil to start with and forevermore.JMHO

 

There have been MANY oil discussions here in LT1 Tech. Synthetic oil has some real advantages, but if you change your oil every 3-5k miles with 5w30, you're LT1 will last for hundreds of thousands of miles before the cause of failure is the oil... You'll spin a bearing, throw a rod, blow a head gasket, etc... long before your oil fails you...

There are some oils that perform better than others depending on your climate and how you drive, but the manufacturers improve or at least change their formulas fairly frequently, so it's really hard to say that any one oil is best...

That being said, I've used synthetic since the second oil change...

Don't use a straight weight oil. It won't flow well enough at 100*F to protect you at startup... It will probably flow well enough at 100*C (212*F), but most wear happens around startup... A good 0w/5w/10w 30 or 40 is what you want...