They used oils with lubricity/wear additives like ZDDP plus didn't have excessive spring pressures like many of us use when we build a modified engine.

 

I don't know for sure but I don't think the broke them in at all, the oem camshaft was much milder than a performance cam. Even the book 'how to rebuild a small block chevy' by D. Vizard, which is an older book geared towards a stock type rebuild, makes no mention of breaking in the cam.

 

That's interesting. I wonder if that's why older cars had engine break in guidelines for the first 500 miles or so. I wonder if this accomplished the same thing.

 

At one time, at least some Chevy engines were run in for a brief time using propane or some such gas. I heard that this was no longer done, at least to the crate engines- but I have no confirmation of this, all hearsay.

 

here is a useful document on break-in : how and what

http://www.zddplus.com/TechBrief12%20-%20ZDDP%20and%20Engine%20Break-in.pdf

- Stephen

 

cam break in

First the oems used quality cam-blanks,I know several cam grinders(small operations) they tell me most mass cam suppliers buy cam blanks from china at 10 to 12 dollars@.they tell me a older core reground from oem stock is far better. I use a molly past on lobes and lifters always new,sensible spring pressure,they ar broken in with in 50 miles or less. or purchase a known cam with decent iron quality. cliff

 

Cams for as low as $14.00.

 

Cams for as low as $14.00.

cam blank,is un ground cast cam.

 

Back in the early seventies. I used to buy General Kinetics cams for $14.00 each ( orders of 10 min).