Its been posted a bunch, but I wanted to ask for my specific application. I have a 69 block with hyper pistons, cast rings, COMP cam, stock heads and oil pump. I know i need some kind of oil with ZDDP additive. From what I've read, i should do the initial start up with conventional, change it out after the first 30 min of break in time.
Once I've done that, can I change to synthetic or should I stick with conventional for the first few hundred miles for overall break in?

Sorry for posting the same stuff over again, I just wanted opinions on my application, since everyones build is different.

 

i'd avoid the synthetic for a while.
ive been using valvoline vr-1 racing oil for years. it has the added zddp in it.

 

I'm assuming I should run 10w30?

 

Zinc additive for break in- 10w30 is fine- at least that's what we've used in the multiple engines built.

 

if its a hydraulic cam/lifters, you'll need oil with zddp for the life of the motor/cam. not many oils have it today.

viscosity is up to you. 10w-30 is a good break in oil.

theres horsepower to be had in oil. a friend of mine builds pro stock motorcyle engines. one day he tested a bunch of different oils on the dyno. he found that redline oil made the most power. sorry, dont remember the viscosity. i'm sure it was "thin".
another guy told me he picked up 7 rwhp on the dyno just by using royal purple synthetic gear lube in the rear!

anything to free up h.p. is a good idea. the only reason i personally dont use synthetic oil is alot of people complain about leaks after switching. could just be a rumor though?