synthetic oil now recommended...

[gride300]

what year did pcm start recommending synthetic oil? and what brought them to this conclusion? i'll use it if it provides better lubrication. i'm still going to change oil every 50 hours/120 days. i have an 05

[horkn]

I guess the bigger question is when or if PCM started to use roller engines? I think all PCM gt40 efi motors are roller tappet and not flat tappet motors.

Unless the synthetic oil is specifically made for flat tappet engines with no "energy conserving" label on back, those oils are not made for flat tappet motors. Redline synthetic oil is the only synthetic oil I can think of at the moment that is designed with high levels of ZDDP to protect flat tappet motors.

I don't know much about the Excalibur or the zr6, etc GM motors, I hope those would be roller cam motors.

[teamseal]

The GT-40 was not a roller motor.
PCM started using the Vortec Motors sometime in the late 90's. All the Excalibur motors are Roller motors as are the Pythons.
I run Royal Purple 15W-40 in both my 502 ex-Python motor and in my ZR-6/ 409 Ski 200.

[horkn]

I wonder why Gt40 5.8's are not roller motors. They had been roller motors in 5.0 mustangs since the mid to late 80's, and there are easy roller conversions for 351w's to go to rollers.

Weren't the 351w HO's in the lightning's roller motors?

Yeah, I'm aware that GM motors could be had, even back in the 70's GM derived PCM power options were there. When the python 8.1 came out that was the first time PCM had used GM blocks in a while. Then the excaliburs became an option around 02 or so as well.