My 360 magnum crate engine is a BEAST in my '67 dart. It dyno'd at 375hp, 420 lb-ft torque (builder was Performance Injection Equipment). I have 2.76's (cruiser) in the 8.75 chunk (posi) and if I hit the gas a bit too much when the light turns green, it spins both 215 60R/15 rear tires. My A904 builder (A&A Transmission) put a lower 1st and 2nd gear in there to compliment the 2.76 rear (and it is a very nice compliment).
Anyway, I notice that my engine has what I recognize as valve or lifter chatter. I thought it sounded like the passenger side, and when I moved over there it sounded like the driver side, and then I settled on the middle, where the lifters are, under the intake. Anyway, I consulted the builder and got, "it's common for the 360 magnum to have this noise." I did some digging online and indeed many report this issue, some saying it's a lifter preload issue, often with much adjusting they can't solve the noise, although a few succeeded (I admit I don't understand this as these are hydraulic lifters). Some said that they got rid of the noise by using a heavier weight oil. I mentioned that last bit, because I also noticed that the oil pressure in my engine is like 60 psi when cold, but after it's all warmed up, it's more like 10 psi/1000 rpm. So, for example, when cruising at 2500 rpm the oil pressure is 25 psi. I guess that's OK, but lower e.g. than my slant six was, which ran, warmed up, at closer to 20psi/1000 rpm (also using an A904). Do 360 magnum's run at lower oil pressure? My engine builder added, unrelated to the valve noise issue, but rather directed to the oil pressure question, "...you can run heavier weight oil if you're uncomfortable with the oil pressure..."
So, what are your thoughts on the lifter chatter issue with the magnum engines? I currently use Lucas Hot Rod oil 10W-40, as recommended by the engine builder. Anyone use heavier weight oil to address either lower oil pressure or lifter chatter noise in a 360 magnum? I live in a warm climate, California, so heavier weight oil shouldn't be an issue for me. I don't mind the noise if it's not damaging the engine. It's not extreme, but from years of experience with many many engines, I immediately recognized it and would otherwise find it annoying.
Thoughts?
Brian