70T/A400

iTrader: (2)

I like the Schaeffer's 5W30 synthetic. It's made locally and has a great reputation.

Scalpel

iTrader: (4)

Do you have data to support this other than what is printed in their advertisments? Or is this just your opinion?

Patman

With factory built engines I think it's safe to run synthetic from day one, but for rebuilds my rule of thumb is to start out using 10w30 dino, then do an oil change at 100 miles, 500 miles, then 3000 miles. Go to synthetic at 3000.

hourang

iTrader: (6)

amsoil 5w30

ChevyNo1

Thanks much Patman!

dhdenney

iTrader: (53)

Ford, Chevy, or Dodge. Import or American. That's my opinion.

z2802sunsetls1

iv tried m1 ,rp, castol syn my car burn on all those oils then used redline havent had a problem since

whorunit

I had an 89 Chevy pickup with the 5.7L that had 275k miles on the original engine, tranny, and rear end when I sold it. The oil was changed using regular Castrol GTX 10w30. If the miles were mostly highway the oil was changed at 5000 miles, and 3000 for city and towing...which was done often since I have a lawn service. The engine used approx 1 qt every 3000 miles since it was new. The engine never smoked, ran perfect, and the engine was never touched.

Tiger2o69

iTrader: (16)

Hp tv dynoed a 8 rwhp gain from a full change to royal purple . I know this could just be to help sell the product. But do u think hp gain is achievalbe w/ other good oils considering that it does help friction and heat? 8 seems like a lot but when i started thinking about the less friction the more power you get to the ground and also the cooler the more power you make. So could this actually be achievalbe. not just from royal purple but other good oils?

MyLS1Hauls

iTrader: (2)

I'm sure the engine did pick up 8hp...because RP 5W30 is pretty thin oil..thinner oils make more power (thats why NASCAR guys qualify with a 20W oil). When I used it in my car, it burned about twice as much as with M1 10W30. I now use 0W40 M1 and it now only uses about 1qt every 5k miles. Guys at AutoZone always ask me what I'm using that oil in. When I tell them, they look at me funny and say you can't use it in that motor. I just laugh.