Cracked forged steel I-beams?

[Fourcam330]

my bad.. mis-interperted what you said.. and yes it does.. (beg for a good bottom end)

Well, a well tuned 96-98 Cobra's rods "can" handle 600 bhp for awhile.. but they will ventilate the block almost guaranteed if you keep it up..

Also, maybe SVT put those rods in the engine on purpose, to keep people from modifying their engines, and if they do, guaranteed to ventilate your block.. (expensive way for the consumer to learn not to hop up the boost on the Whipple)

NP. I would say that running anything over 400-450rwhp on the older N/A 4.6L PM rods would be asking for it over time. Also, though I understand your thinking regarding Ford teaching people an expensive lesson, I can't see them actually doing that on purpose. Thankfully if they do the iron block should help keep everything contained.

 

[Emmerson_Biggins]

Actually until the C6 Z06 7.0L came around Ti rods were not suitable for 100K miles of street driving. Ti is strong/light, however, it fatigues very quickly after being scratched. Ti rods have been used successfully in exotic Porsche's, Ferrari's, etc. however, they usually require replacement after 30-50k miles.

They may well not last 100K in this application as well, but they are not an alloy as far as I'm aware (nothing new from the whiz kids at GM). Not sure how the rods get scratched?? I'd like to hear more on that. The two-wheelers have been using them with great success and insane RPM for quite a long time.

Billet Al rods, as previously stated, are great for all out drag applications but they need to be replaced after 100 passes or so as they stretch. I've never seen one become at all brittle. If you leave them in too long you'll tend to see PtV clearance problems.

If you build an engine with deck clearance to accept the stretch of the rod which is mandatory with aluminum rods, it will work harden and fracture long before it stretches far enough through operation to kiss the head.

Billet steel rods are IMO still the best choice for long term durability in a street or street/strip motor.

Then you are going to have to put them in this engine, because they are not going to be there when you buy it.

 

[Fourcam330]

They may well not last 100K in this application as well, but they are not an alloy as far as I'm aware (nothing new from the whiz kids at GM). Not sure how the rods get scratched?? I'd like to hear more on that. The two-wheelers have been using them with great success and insane RPM for quite a long time.

If you build an engine with deck clearance to accept the stretch of the rod which is mandatory with aluminum rods, it will work harden and fracture long before it stretches far enough through operation to kiss the head.

Then you are going to have to put them in this engine, because they are not going to be there when you buy it.

I didn't say that the rods scratched, I simply stated that Ti weakens quickly after being scratched.
When talking about rod stretch, I wasn't inferring the type that occurs every time the engine goes from cold to operating temperature. I've only seen two motors with Al rods have PtV issues; in both cases the rods had close to if not over 100 pases, and stretched when they failed the motors.
Billet steel rods (with quality rod bolts) have been used successfully in 9000rpm 3.55" stroke modulars, and so far 8500rpm in 4.165" stroke apps. When I blow the stock shortblock, in the GT500, I in fact plan on using Oliver billets and custom CP pistons. :beer: