I know several people that run Rotella and swear by it.
I run straight 50 Valvoline Racing for over 20 years and never had an engine failure related to the oil. opc1

 

Mobil 1 is my #1 choice.

Valvoline Racing oil is #2.

 

Mobil 1 15w50 EP - the bottle with the gold cap.
It's real slippery.

 

My engine builder recomended Valvoline VR1 20/50 racing oil. Said that they run it in all the customer's engines and also in the race boats.EDIT LOL i was in the middle of this and realized that you are running a stock set up. I have a N/A 572ci. Check you manual but my dad ran Rotella in everything he had...

 

Valvoline VR1 20/50 racing oil.

 

My father asked this question to directly to Bob Teauge a couple years back. Bob said less than 500 hp, straight 40w and more than 500 hp straight 50w. That being said I have always ran VR-1 straight 50w.

 

Have always used Valvoline VR-1 40 wt on all motors we have built.

 

I use Amsoil 15w/40 synthetic Marine/Diesel oil. I also use there filters.

 

Rotella 15w-40 here.

 

I use Mobile 1 V-Twin 20/50

Prolly overkill for a stock 7.4 but what the hey

If you'd like a few opinions ............

http://www.offshoreonly.com/forums/general-q/107808-marine-lubrication.html

 

Rotella 15-40 in mine. Talk to some truck owners.

 

He's located in Canada where water is on the cool side, also temp. I would not recommend straight 40 wt for that area.

 

He's located in Canada where water is on the cool side, also temp. I would not recommend straight 40 wt for that area.

Damnit ..... I bought the wrong body oil !!! What body would you guys recommend for cold Canadian waters?

 

I ve been using Royal Purple after hearing many good things 20w50 so far so good :blush:

 

I have also been using the 20-50 Royal Purple with good luck.

 

I have nothing good to say about 20-50 Royal Purple of any kind.

 

I run Amsoil in everything I own. They also make a very good water resistant grease for trailer wheel bearings.

 

502/415 MAG-MPI and since day one I've used Merc. 25w40 and Merc. racing oil filters. 425 hours with no oil related problems.

 

Mobil Delvac 15W-40 in my last 3 motors with good results. 25-30 hour max change intervals. With the clearances in my engines there is no need for a thick 50w oil. Upon teardown of the last engines, the bores looked almost like new, no scoring, minor skirt wear, very visible crosshatching. Lifter rollers and cam lobes, journals etc..... all looked awesome. One had 360ish hours, other was 136hrs. They were tore down due to adding more cubes, heads, cam etc... They all had awesome compression numbers.

Napa Gold oil filters.

FWIW, My Father's 84 Merc 260hp 350 went 900+ hrs on Mobil 1 10W-30 before it needed rebuilt. Engine did not burn any oil at teardown. It was rebuilt due to an exhaust manifold riser leak that shot water into the cylinder bending a rod.

 

502/415 MAG-MPI and since day one I've used Merc. 25w40 and Merc. racing oil filters. 425 hours with no oil related problems.

Same here. Merc oil and filters, no problem ever. Stock 502's.

Decided to try M1 oil and filter for this yr because of all the opinions on it. We'll see.

A friend has been running the M1 in his blower motors last 3yrs. Every time he checks the oil under the V/C, it always has condensation in it. Changed to Valvoline mid summer last yr in 1 of the motors, condensation went away immediately with that oil change. Strange

 

US1, do you think its because the syn takes longer to heat up?

 

That was his thoughts also.

 

That was his thoughts also.

US1Fountain, I'm running a full synthetic oil in my 454 mpi engine and I want to back out of it. Is there a safe way on switching back to regular oil??
Thanks

 

15/40 Royal Purple. Lowered my oil temps 20*

 

US1, do you think its because the syn takes longer to heat up?

Come on now... Syn takes no longer to heat up vs conventional oil. I have 3 vehicles with oil temp gauges including the boat and I have run both in all the engines. There is no noticeable difference in either. Synthetic does handle higher heat better than conventional. It's more shear resistant and resists viscosity breakdown.