[DeTomaso] STD 351C flywheel and BOSS flywheel

[JDeRyke at aol.com]

In a message dated 11/6/10 3:55:42 AM, detomaso at luleweb.se writes:

> What is the difference between an STD 351C flywheel and a BOSS flywheel?
> 
Looking at the 1972 Ford ORR Component Comparison,   a '71 4-V and CJ had a 
cast iron assembly with a 28.2 in-ounce imbalance. A '71 Boss flywheel was 
a high-nodular cast iron with 27.3 in-ounce imbalance . These balance 
weights matched to different harmonic balancers in front (the Boss unit was bonded 
as well as pressed together and was heavier than that of a 4-V or CJ, also 
with different imbalances). 
FWIW, there were 50 engine parts that were specific to the '70 and '71 Boss 
351 vs the 4-V and CJ models, and they really needed to ALL be there, not 
piecemealed together over time. Aftermarket steel or aluminum flywheels are 
much stronger and more nick-resistant than stock iron; no serious engine 
builders use any stock flywheels anymore. Some competition sanctioning bodies 
prohibit their use.

> Approximately how much rpm can a STD flywheel take?
> And a BOSS flywheel takes?
> 
No good answer to this; unless you modify the engine, a 4-V or CJ with 
stock hydraulic lifters & cam won't rev much past 5200 rpms under load so a 
stock flywheel is probably safe with them- unless you miss a shift or try using 
one that's damaged. A Boss or HO with a solid lifter cam will go to 6500 
under load more-or-less safely. But at least one modified Pantera was nearly 
sawed in two by flying debris during a drag race when a stock flywheel (
unknown type) and clutch disintegrated. It really isn't worth the risk of using a 
stock flywheel of any kind if you're truly going to drive the car as it was 
intended. If you're going to use one anyway, I would also install a good rev 
limiter and set it to the above limits to start. Show cars and downtown 
tourers are of course just fine with any flywheel. Good luck- J DeRyke