safe rpm limits for pontiac 455

[77TA]

what is the safe rpm limit for a 455 with studded mains and eagle rods and trw pistons ? I plan in shifting about 5500 or lower but would like to know the safety margin. Ho books I think said 7000 was safe with SD Rods seems like the Eagle rods would be at east that good. Like I said I don't PLAN to explore up anywhere close to that but there are such things as missed shifts and stuff.

[77TA]

what is the safe rpm limit for a 455 with studded mains and eagle rods and trw pistons ? I plan in shifting about 5500 or lower but would like to know the safety margin. Ho books I think said 7000 was safe with SD Rods seems like the Eagle rods would be at east that good. Like I said I don't PLAN to explore up anywhere close to that but there are such things as missed shifts and stuff.

[Bob Dillon]

With your combination, I'd say you could
shift that motor at 5500 all day and never
worry. Might not even have to rev that high;
many people here have reported lower ETs and
higher MPH by shifting 455s at LOWER RPM. I
would say these are probably the unported
cylinder head crowd. Good luck.

[Paul Spotts]

You can safely shift to 6000 but won't need to go that high. bearing clearances,rod bolt stretch, crank condition and balancing all make important factors. I always suggest a rev limiter like a MSD unit for cheap insurance.

[77TA]

I hope to get a rev limiter for christmas next year. I am about tapped out money wise and I can't find a cheap limitor. Id like to stay with my HEI ignition and most I have seem are like MSD ignitions with rev limitor functions. I wish there was an add on that worked with the standard HEI. For under 100 bucks

[Big Injun]

On a 455 the torque and HP cuvres usually meet around 5500 rpm. We have several racers in our Pontiac Drag Days program running the Eagle rod, TRW and stock stroke crank combo down into the 10's.

One of our racers, Tom Cwayna, running a '68 Bird with a set of SD Performance ported #62 heads and 4.10 gears shifts at 5400 and runs it out the back door at 6100. He just ran 10.67 at 127 mph in an all steel car with slapper bars.

------------------
www.PontiacDragDays.com (http://www.PontiacDragDays.com)
Dave "Big Injun" Anderson

[This message has been edited by Big Injun (edited 01-07-2000).]

[GP-K]

77TA,
There is an add on MSD Soft touch for just under $100. MSD has two types of Soft touch, one for their 6T ignition, and another for non CD ignitions, using points or standard electronic triggers (ie HEI). They are available from any major parts house, like Jegs or Summit.

Good luck.

[Nathan]

Just a note in regard to Big Injun's comment about hp and torque meeting near 5500 rpm. This is true of every engine, but at 5,252 rpm. The formula for hp is hp=torque x rpm /5,252. So when rpm = 5,252, hp = torque.