Which stock flathead rods are the strongest?

Which do you believe the is the strongest Flathead connecting rod between these regardless of bearing type and size. 8BA , 21A , or the 29A I'm thinking they may be very close but I would just be guessing.

 

Well not a strength issue but the early ones are full floating bearings which i ***ume makes quite a difference

 

they are all made from the same alloy. my vote goes to the 8ba only because the later engines generally seem to have been maintained better and less prone to alignment issues and egg shaped big ends...

 

My vote goes for the brand spanking new French 8BA-style rods available for $125 a set from SF Flatheads...

...now, if they only came in the early 1.998" journal size.

 

french military surplus right? they have some good deals on rifles too. never fired and only dropped once

 

Thanks Ernie, I checked out there site, you can't beat the price that's for sure, I can use the larger journal size on a 4 1/8 crank I have as well. I was going to use h beam rods but I really don't have a problem with stock rods......knock on wood

 

Theory would say use the 21A-29A type depending on size need...
8BA has locked bearing, so if it distorts from high load. BANG.
Yunick discusses this--rods subjected to enough to upset lower end either pull the hole oval a bit or hammer the bearing shells so they curl in at parting line--either thing pulls parting line inward, s****es the oil away, and siezes the thing so it breaks.
Overloads in order of severity, I think;
Detonation--probably fatal no matter what
Load at top of exhaust stroke at high RPM is biggest load for normal engines...much greater than power load! Low revs of FH probably a real plus here.
Load from power--probably not a big deal for the rod except on extreme engines like fuelers and Formula ones...

Remember, lots of 9 second fuelers in the day when 21A rod was about the only choice.