Pontiac 455 Amsoil

[pitts64]

I've had good results using Amsoil in my Pontiac 455. Its a high performance engine and uses fast bleed Rhoads lifters to make the long duration cam streetable at idle. http://www.rhoadslifters.com/

The engine builder recommended I use 15-40 Rotella years ago but I like the synthetics idle stability with the Rhoads lifters.

I have 10-40 AMO in there now but was looking at the AME 15-40.
I noticed my engine seems to run a little stronger right before full warm up with the oil pressure right at 20 at idle, it usually drops to 15 at idle when fully warmed up (160-170 degrees).

My car stays in a heated garage and is only driven in nice weather.

What would be the performance difference between the two?

Thank you,
Jeff

 

[tackleberry625]

I think Pablo or Gary Allan would be able to answer your question(s) best about Amsoil since they are distributors.

 

[Pablo]

Different base oil mixture. The 15w40 has even less viscosity index improvers than the 10W-40 (neither has that much anyway).

The 15w40 is heavier duty and has a bit stouter additive package. If you don't need the 10W, the 15W is the way to go.

 

[Steve S]

The 15w/40 Diesel marine is the Amsoil of choice for your engine and conditions.Real good stuff.

 

[jorton]

In 73 I learned to drive in a 2 door Bonneville 455. I remember pulling a snowmobile trailer at night in a blizzard with Mom and brother in the back seat, dad in the passenger seat. I HAD NO IDEA WHAT IN THE HECK I WAS DOING, but we made it(cold sweaty hands) to the cabin in one piece.

I have a feeling if you put in some Shell oil you smoke one back tire all the way to the next stop sign with your Pontiac 455!

 

[pitts64]

Thanks guys for the info. I bought the 15-40 and re-opened my account with Amsoil.

Jorton, I use 87 Shell gasoline. Those 455s have tremendous amounts of torque.
Check out the video, this is with a 2.56 posi.
http://www.youtube.com/watch?v=EoM8MafcA-A