I have a 72 El Camino with a 454 (LS5), Crane Cam (hydraulic lifters - NOT A ROLLER), Hooker Headers, Edelbrock intake and Carb. The car also has a GM HEI ignition. The engine has about 30,000 on the engine.

I currently run a Non Synthetic oil (Valvoline Racing or Castrol).

My question, should I change to a Synthetic (Mobil One - Valvoline Racing) or should I stay with the regular oil.

I have had a pretty good talk to a fluid dynamics major and he said it like this. SYN oils viscosity is the same as the petrol based products but it is alot thinner. He builds transmission and tells everyone who he sells a tranny to use a gl-3 petrol based gear lube because it sticks to the gears better. I currently run a full synthetic in my 4 banger turbo but it has ran synthetic since the day i got it.

You shouldn't switch oils after running it for 30k...I only run only petrol based products in my chevelle...

Main advantages of SYN is that it can keep that viscosity for a longer period than a petrol based product. So what right, you change your oil every 3 months/ 3000 right

I think it depends a lot on how hard you run the engine and how hot it gets.

Way back when synthetics were new, I was racing a 327 on an oval track. I started out with natural oil, stock oil pan, no cooler. I found that every time I came back off the track, the oil pressure was lower than the time before. Every time. I switched to Mobil 1, and the oil pressure stayed stable for the rest of the season.

For most street use it probably doesn't make a lot of difference if you change it at appropriate intervals.

I see no reason for a synthetic at all

I agree with jambb. These cars lead a very easy life. They'll never see high mileage or harsh conditions that would make the synthetics worthwhile. I put in whatever's on sale and change it often.

Tom