IMO as long as there’s oil in it, it’s the right viscosity, and it’s changed on an appropriate interval, it doesn’t matter…

My Ironheads get VR1 conventional, my newer Harleys get VR1 synthetic. I run conventional during engine break in on all bikes. It all does the job. Twin cams are hot SOBs, if they happen to run cooler on synthetic seems worth a couple extra bucks to me. Whether they do or not I dunno, however.

 

One thing I do know for a fact and many have said that when it actually comes to breaking in a motor, a fresh build, Dino oil is the best for breaking in.. I've been told that by some of the top builders I know. Then after that you want to use what you want that's fine..

 

Only thing with dino is you'll have to change it twice as often especially if you run in high heat areas like AZ.

 

WTF? 60Gunner hasn't been in here spreading his wisdom, yet? Give it time...

 

No matter what the oil in my bikes I never go over 3k.. My hot rod Evo is 2500 miles..

 

Well might as well run dino then,I run Amsoil and change at 5000 miles. (my indy is an Amsoil guy)
I run Mobile 1 in my Camaro SS and same at 5000 miles.

 

With syn you could very easily go 10,000 miles. I change mine at 5,000.

 

But if you change to SNY it will leak oil all over town. That was another myth.

 

Answering the original question.
Nope.

 

From Bob is the Oil Guy...

https://bobistheoilguy.com/motor-oil-104/

I'm running Schaeffer's 707 V-Twin 20W50 in my Twin Cam.

Top end was freshened a year ago.

Engine builder said to break it in with VR1, which I did, and that if I wanted to run synthetic, fine, but put at least 2K miles on the motor before doing so.

Did that as well.

He recommended running shortened oil change intervals no matter which type of oil I decided to use.

Oil is cheap.

New motors ain't...

As far as I can tell, oil temps have dropped slightly.

YRMV.