How long or how many miles for breakin oil on 472 hemi crate MP motor?

Opinions will vary widely. I'd change it/filter) after the 30 minute cam breakin for sure, not sure how many miles I'd go on the 2nd one

Amsoil Break In oil says 1000 miles then dump it--I don't know what you have in there. The Amsoil Hotrod oil has proven to be great stuff for flat tappet cams as well as Brad Penn and many others. We have a ton of choices for good zinc rich oil now. On a new engine I like to dump it after a few days --I figure there has to be a fair amount of stuff in there from the new cylinder walls, ring wear-in etc so I want that first oil out asap like a final rinse. Just my 2 cents worth. I always guessed that very first running produced the most contaminants and after that there should be no more metal particles.

Thanks Crabman. Actually there is Amsoil breakin oil in the engine. I plan on using Amsoil Hot Rod Oil w zinc for followup. I have 200 miles on the engine now. Good advice for clean-out. Should I stay with breakin oil even if I dump it up to 1000 miles?

I would swap to the Amsoil Hotrod stuff--It is an oil designed for normal intervals--the break in stuff says right on the bottle dump after 1000 miles--I would do it a little sooner --We use that brand for the first time in the Amsoil Engine Challenge--I always had it figured for snake oil like all the rest but we ran a soilid lifter engine with approx 170 on the seat and WAY over 400 over the nose and when we took that thing apart for tech I was astonished! The lobes looked better than an I have ever seen in any flat lifter engine--EVER! I have ran about every combo with every oil out there--we have done a lot of rules engines that have to run flat tappets in circle track applications and I have had access to all the "secret" Nascar stuff but am a true believer in the Amsoil line of products--I am SURE others are just as good but when I needed it to work--it Did!!! If that Hemi was mine I would put a few hundred miles on it and then go with the Hotrod stuff in the weight I liked. Happy Hammering! If you have never had a Hemi you are in for a treat--they are a little lazy down low but about 75 MPH on up until you chicken out they are untouchable!

I too like to change the break in oil pretty soon after initial cam break in... no matter how clean and careful the assembly is there is bound to be some crud in the oil and filter. By then, the cam should be broken in and any high zinc oil should be fine.