best how to run-in 340

[polywideblock]

when new cam arrives will need to run-in 340 , so what is the best way to this.
these will be using

to break it in, but need to know what revs at how long etc.

 

[kiwigtx]

I'm no expert, but typically base line around 2,000 RPM, and varying up and down at random for a duration of around 20 minutes.

Make sure to prime the oil pressure first, have timing set, and vigilantly check temperatures and oil pressures during the run-in period.

 

[Demonic]

I'll agree exactly with that above. Maybe 2100-2200 as a minimum. Definitely alter the RPM's a bit. The lifters MUST spin in their bores. Make sure you have known good gauges installed. The break-in oil is an excellent idea.

 

[oldbee]

And then, I would test drive at varying speeds with at least 5 or so long coastdowns from 40/50mph to seat the rings good.

 

[Johnpat]

Agree with oldbee,gotta have back pressure
to seat the rings

 

[moper]

Not sure what camshaft you got, but some notes:
During install, before you lube the cam lobes, verify lifter rotation by installing the cam and lubricating the lifters with WD40 only. Mark the top of the lifter and bore, and turn the engine by hand. Swap around any that don't rotate on their own until they all do.
Once rotation is verified you can lube the lobes with a paste-type break in lubricant. Don't put anything on the lifters but a small amount of engine oil.
Remove the inner springs, or run weaker singles if the camshaft requires true dual springs.
Ensure the engine starts immediately - pre-fil the carb, make sure the cooling system is set to run, and pre-oil the engine with a priming tool - not the starter.
Start it and run it between 1800-2500 for 20 minutes. Then re-install the inner springs and you're good to go. I would try to avoid long idling periods for the first couple hours of running. The cam is only oiled by splash. So at idle speeds it's not getting much oil.