Would you use Mobil-1 as the initial break in oil? And if so, what weight.
If not, then break it in using 10-40 premium grade oil then switch over?

I am considering using Mobil-1 this time around, just want to get the right procedure down.

Thanks

Don

http://home.rochester.rr.com/dchapman/Plate.jpg

restored a 70 Judge at: http://home.rochester.rr.com/dchapman

Would you use Mobil-1 as the initial break in oil? And if so, what weight.
If not, then break it in using 10-40 premium grade oil then switch over?

I am considering using Mobil-1 this time around, just want to get the right procedure down.

Thanks

Don

http://home.rochester.rr.com/dchapman/Plate.jpg

restored a 70 Judge at: http://home.rochester.rr.com/dchapman

Don:

You'll get PLENTY of opinions on this. On my new 455HO my machinist specified Mobil 1 5W30 for the dyno break-in and pulls. That's also what I'm planning to run in it for good - unless my OP gauge "tells" me I need a higher viscosity rating.

Later,
Lloyd

'72 Formula 400 - soon to be a 455HO, TH400, A/C, etc.; Lucerne Blue with Medium Blue Interior
Restoring a '72 GTO 455HO, TH400, A/C, etc.; Sundance Orange with Parchment buckets

I am almost ready to fire up my 400 for the first time also. The Crower book says definately do not use synthetic oil for initial break-in. Also no multi-viscosity oils either. They say use a high grade 30, 40, or 50 weight oil and put in a can of GM EOS part #1052367. I am going to do what they recommend. Everyone has a different way of doing this that I talked to but I will go with Crower and keep my fingers crossed.

With a flat tappet cam I would suggest using a conventional oil. Make sure to change it right after the initial cam/lifter break-in. Teh cam lube will plug up the oil filterwhich means most of the oil will bypass the filter. I also suggest changing after the first 100 then synthetic after 500. If you are just racing your engine and had the block honed with torque plates I would suggest going to synthetic after 10 passes or so. If you didn't have it honed with torque plates I would suggest a longer break-in because it will take a lot longer to seat the rings.
I have seen a race motor's rings not seat with synthetic oil and had to put conv. oil in it to get the rings to seat. This was in a national record holding A/stock automatic stocker.
Bartman

Ponies run but Birds fly

I agree with Bartman on using Syn. only after several passes down the race track..I use
regular 10/30 or10/40 for break-in only....I have
heard of some people using SYN for break-in but I
won't chance it ?? This system really works so why
change it...Unless you enjoy tearing do motors every-week,if it ain't broke don't try to fix it..
The Syn really works,both on keeping the engine clean,also is worth H-P... Dave..1033/stock http://forums.performanceyears.com/g...s/icon_eek.gif