Originally Posted by Chevy55 (Post 681789)

2023 NHRA RULE AMENDMENTS

Beginning January 1, 2024, SFI 29.1 flexplate mandatory on all V-8 vehicles. Any car running quicker than 9.99, SFI 29.1 automatic transmission flexplate and SFI 30.1 flexplate shield mandatory. See General Regulations 2:12, 2:14.

Originally Posted by Billy Nees (Post 681782)

Now just to be "fair", this ruling is going to apply to all V8 bracket cars also right?

Originally Posted by Billy Nees (Post 681795)

why should it apply to a "U/SA 273 Mopar" or a P/SA 301 Pontiac that rarely if ever sees over 6 grand?
And where am I supposed to find this 301 Pontiac SFI approved flex plate?

Originally Posted by Larry Hill (Post 681747)

I don’t think the ring gear knows any difference if it’s being spun to 7000rpm by a BBC, SB2, SBC, V6, or a 151.

Originally Posted by Mark Yacavone (Post 681793)

Yes..Okay.
So how does that apply to U/SA 273 Mopars?

Originally Posted by SSDiv6 (Post 681802)

There are many variables applicable to flexplates.

Lots of considerations such as horsepower, RPM range, size/diameter, one-piece or two-piece design must be considered.

The SFI 29.1/29.2 test entails the flexplate turning 12000 RPM's for one hour. However, the test equipment does not simulate the effects of heat, engine load, flex, having a torque converter attached to it and transmitting the horsepower and torque to the drive line. When applicable, add a car with a transbrake and/or rev limiter.

I consider both the SFI harmonic balancer, flexplate or flywheel/cluth a safety item. In the early days of Modified Eliminator, with heavy flywheels and OEM flexplate, saw them come through the floor, cut fuel and brake lines many times causing injury and damage.

Although high in cost, my preference are the Reactor Products (without the inertia ring) and Meziere flexplates. They have a great selection of configurations and weight for different end applications.

Other great options are the ATI, TCI billet line and ATF

Originally Posted by dragracerray (Post 681808)

SS,
Two Steps cannot be good for a flexplate either. Ray

Originally Posted by Billy Nees (Post 681795)

This ruling only applies to S/SS cars and I'm not saying that in most cases it isn't a good idea BUT it doesn't apply to a low 10 second bracket car so why should it apply to a "U/SA 273 Mopar" or a P/SA 301 Pontiac that rarely if ever sees over 6 grand?
And where am I supposed to find this 301 Pontiac SFI approved flex plate?
Maybe a re-think and a change to 11.99 or quicker might be prudent?