2000 less than an comparable 454

 

I had a 429 that I ran over 7200 for short burst and would push 7000 for a mile or two. 6000 all day. It was a Cobra Jet with 4 bolt and steel crank.

 

limiting factor are the rod bolt type square head versus ovalhead .Some people also call oval head- football head these will take more rpm.square head rods should not be pushed to hard 5500+.I used a set of ovalhead rods that were totally gone over smoothed shot peened ect. at elmirage and bonneville in a car for 3years.575 hp 6400 rpm 2 bolt main cast crank is very strong for this level of performance.

 

As long as you have properly machined and balanced stock components, 6,000 rpm shouldn't be a problem.

As noted above, Broached Rods(square bolt seats) shouldn't be used in any Ford HP engine(and weren't installed by Ford). HP Ford engines always used Spot Faced Rods with Oval(or Football)headed bolts.

Spot Facing leaves more material in the Rod shoulder for strength and is preferred to Broaching, which is a straight cut that removes lots of material. It can lead to Rod failure.

Of course, that rpm requires matched components in other areas as well, but the bottom end once properly set up will be plenty strong.

Hope that helps.

RR

 

what would be a reasonable redline for a balanced 460 bottom end? I understand valve float , spring rates,cam,intake etc. more concerned with con rods,spining bearing, breaking bolts ,that kind of mayham.

The weak link is the OEM rod. How and when it fails is anyone's guess...that's just how connecting rods are in most any brand/type engine, but the OEM 460 rods are notably weak by design.

The two extremes: I know a guy who was driving at a steady-state 4400 rpm and a rod broke; on the other hand I know another guy who let his wife make a pass in his mud-pulling truck with a bone-stock OEM 460 bottom end and she stayed in low gear and recorded 8200 rpm for 21 seconds...and the engine lived.

Your specific question is not specific enough. Totally bone stock engine? Generally, I'd say 5500 rpm or less and it should live for awhile. Rebuilt bottom end with lightweight aftermarket pistons and prepped rods (smooth beams, etc)? Ought to last quite awhile to 6000+ rpm.

LO

P.S.: I am of the opinion that the OEM rod--whether CJ-style or passenger car-style--essentially has the same level of strength. It doesn't matter to me whether the rod is spot-faced at the shoulder (CJ) or broached at the shoulder (passenger car). While the spot-faced rod is certainly stronger at the shoulder, the shoulder is not the primary point at where the OEM rods typically break. Every time I have seen one that failed, it broke at mid-beam. DOOE-A rod forgings (aka "CJ rods") are found in both spot-faced form and in broached form, which means that the same forging was used for both rod "types." How could one be stronger than the other when the mid-beam section is the same for each rod? (The shoulder of the big end is indeed stronger.) What usually causes the rod to seperate at the mid beam is a heavy piston changing direction and the top of the exhaust stroke at high rpm. This is why a lighter piston and rod strengthening usually help minimize the possiblity of failure.

 

P.S.: I am of the opinion that the OEM rod--whether CJ-style or passenger car-style--essentially has the same level of strength. It doesn't matter to me whether the rod is spot-faced at the shoulder (CJ) or broached at the shoulder (passenger car). While the spot-faced rod is certainly stronger at the shoulder, the shoulder is not the primary point at where the OEM rods typically break. Every time I have seen one that failed, it broke at mid-beam. DOOE-A rod forgings (aka "CJ rods") are found in both spot-faced form and in broached form, which means that the same forging was used for both rod "types." How could one be stronger than the other when the mid-beam section is the same for each rod? (The shoulder of the big end is indeed stronger.) What usually causes the rod to seperate at the mid beam is a heavy piston changing direction and the top of the exhaust stroke at high rpm. This is why a lighter piston and rod strengthening usually help minimize the possiblity of failure.

Thanks for coming on here and posting that LO. I thought better of it. But then, I wouldn't have sounded as convincing as you did. Excellent explanation.

...and yet still equaling the power output of the senselessly high rpm BBC.

Don't wish they would allow 429 in Super Stock so this one could be settled.

 

The reason I ask this is I am currantly running a steath intake W/a 850 dp, I removed my inner valve springs for cam breakin. I have a t/r w/2x650's(bolt on with plumbing & cable) & my inner spring 's.
I turn 5000 rpm on the nose @ wot now. I have been watchin all the threads about t/r's & single plane intake's. Would there be a benifit, wouldn't it just allow me more rpm ,possiblly blowing up a stock bottom end & way worse mileage? The t/r tugs at me for the looks(they are cool lookin)but I just don't think it's the best choice.

 

I turn 5000 rpm on the nose @ wot now. I have been watchin all the threads about t/r's & single plane intake's. Would there be a benifit, wouldn't it just allow me more rpm ,possiblly blowing up a stock bottom end & way worse mileage? The t/r tugs at me for the looks(they are cool lookin)but I just don't think it's the best choice.

Although it is possible, I guess, to blow up your stock bottom end with the TR, your RPM is going to be due to more than just the manifold type and the size of the carbs. As for milagesphss TR don't kill milage, the speed junkie behind the wheel does. If your A/F ratio is correct, and more FUEL means more air, and the 2 combined equal more power, don't blame the tunnel ram for your lack of control.

 

My boat cruises nice @ 2800 - 3000 rpm. So same rpm with a TR would be about the same mileage?

 

Unless for some reason your motor needs more air and fuel to run at the same RPM just because you changed a TR. All my motors run faster as I open then throttle, because that lets in more air, which picks up more fuel, and that makes more powersphss Now if you have some freaky motor than can burn more fuel with out more air, or you can burn more of each but not make more power/Rpm it may not work out for you.

 

only rod I've ever broken, but it might have had something to do with the little button on the steering wheel and that blue bottle next to me. ( 1990) 472" Ford Dove heads 850 Holley on a FPP's Hi-rise dual plane and a Nos 150 plate system.

The psiton is somewhere ........

I was racing Thunder Pumpkins and Wise ones dad, Big Wes. Hit a roller and got out of it when it settled hit the button again and BNAG !!!!! I was leading, but he had to tow me back to the sand bar


Fastest tow home I ever had, Wes's ( big Wes) dad had a hurricane deck jet boat towed us home 14 miles at better than ski speed devil. Miss you Grand dad (Bob, think of you every time I'm at the river)

Those were the days.

S CP