5W-40 European here. I also sell a little on the side. Mostly for friends and other enthusiasts.

 

I used the GC and the piston slap was noticably louder than even the dino oil it had in it when I picked up the car. I switched to the Amsoil 5W40 and my slap on cold startup is almost totally gone. I would highly recomend it. Also I think the 30wt oils in any brand are too thin for the LS1, especially if you are putting track time on her.

 

I have been using Amsoil Synthetic 20W-50 in my TransAm for the last 2 years +

 

Check the application guide. I think LS1 engines use the SDF 64. I think LT1 uses SDF 32. Dealer here also!

Mec

 

LS1s use SDF32 as the regular sized filter. We can also use SDF64, which is the stock Silverado filter... it's just about a 1/3 longer than stock, but works great.

 

Use to use Mobile 1 and now I am using German Castrol 0w30 with no problems. That air filter sounds cool. I wonder how it flows compared to the K&N.

Bill

 

It certainly filters better than a wet gauze filter (something a lot of people don't like about those types of filters, filtration isn't as good), and it flows just about as well according to the flow tests. And of course, flows quite a bit better than a regular paper filter.

 

 

5W30 Amsoil here!!! Its worth the extra .50 cents over Mobil 1.

 

Im using mobil 1 5w 30 and after reading this thread gona try the change... What about Royal Purple? Anyone want to post thier experiences with that oil.

 

I think I will be trying this Amsoil 5w-30 on my next oil change. I've been using Mobil 1 5w-30 since I've had this car (3 months now or so).

 

I just switched to Royal Purple from Pennzoil dino oil a week ago. At first it was noisy like the Castrol 0W30 I had tried and I vowed to remove it. After a couple of days though it has quieted down. I suspect it has cleaned the rings lands of carbon to some degree. It is at least as quiet as the dino stuff it replaced now and possibly a little quieter. I figure I should try the Amsoil at some point.

 

ive used royal purple and mobile 1 with no issues...why come for i havent heard of amsoil before? so are we talking about 26-27 bucks for it? who locally carries it?

 

Amsoil is sold through a network of independent dealers, as well as some auto parts stores (though not any of the big chains). Its set up much the same way as Redline, or any of the mail order/dealer direct tool companies (MAC, Snap-On, etc).

Take a look at amsoil.com for more info about the product. If you don't have any success finding a price you like locally, let me know, I give the best price I can to my fellow LS1TECH members.

 

will do.

 

I saw Amsoil at a NAPA store once, before I ever saw this thread... if there are any NAPA's around where you guys live. I haven't seen it anywhere else.

 

Not all NAPAs will have Amsoil. Only non-corporate NAPA stores have the ability to carry it. Locally owned and operated may or may not.

 

Can this oil be found in europe?

 

I was checking the application guide the other day, and all 2004 Silverado's (even 6.0) came back as the SDF 32 filter. Did Amsoil perhaps trim the line and only use that filter for all LS1 application's. I guess I will e-mail tech.