Hi to all...newish to this forum site. Love it so far...okay question. I bought a 87 IROC from Gateway Classic Cars. There a consignment shop for the owner of the car...meaning that you dont really get to speak with the owner. My question is the car is here and I dont know what type of oil it was running. Meaning synthetic or conventional. I have a few question. For one, what if it was running conventional and I switch to synthetic will that hurt it, and or VISE VERSA. Like I said I dont know...also what do YOU GUYS recommend, conventional or synthetic? This is an all original 68K 305 (5.0) 5 speed manual. I also was wondering how many quarts it takes....5? I bought an original 1987 dealer shop manual and electrical diagnosis manual online for 100 bucks and it looks like they say 5 quarts with FILTER change. Thanks for the help guys I appreciate it in advance.

 

5quarts and from what "I" know about oil it shouldnt hurt anything changing oil just. What changes with synthetics and conventional based oils is the longevity/change internval between oil changes. Synthetics last much longer than conventional. Thats all i know of the difference.

 

I run synthetic in 4/5 of my vehicles. I've changed them over to synthetics between 30k miles and 130k miles with no issues. All run 5w-30 Pennzoil Platinum or Castrol Edge (which ever is available).

The one car was changed over to an HDEO 15w-40 at 295k which is also spec'ed for gasoline engines. This car now has 444k on the original engine.

It's kind of up to your wallet regarding which type of oil you want to run. Conventional oils are so good now that some say they rival synthetics.

Edit: Yes, 5 quarts with a filter change.

 

Thanks for the input everyone really appreciate it! I'm sure I will be asking questions every now and again and will be talking to some of you all again in the future. Tomorrow the car gets here...will be going thru and seeing how its all operating and what not.