I know redline is based mainly on valve-train stablity, but when does it get to be too much for your enigne? Im running a poncho 455 and have a hyd. roller that comp cams says can take me up to 7k, but i dont think the bottom end can handle it, even though it has splayed main caps. what are all the components that add up to determine redline?

im not using any prupose build lightweight components, but they are all aftermarket. H beam rods, nodular iron crank, splayed mains, double roller timing chain, roller cam, gapless rings, high pressure/volume oil pump.

 

Redline can have so many meanings. As you said, it could be the point of risking valve train failure.

it could be the point where the stress on the rotating assembly becomes to great (i.e rod bolts).

It could be the point where the engine can no longer efficiently operate (i.e. it cant feed enough air fast enough)

As far as the bottom end goes, i would have to say rod bolts. They take the most pressure when the piston is at TDC.

 

Engine life will be greatly extended by either reducing rotating mass or setting an appropriate redline based on the issues involved with the existing mass.

The 455 shortblock has some of the heaviest parts ever known. They will physically cut the block in half if over-reved. Rarely should it be turned more than 5500. If you have completely stock parts I would shift at that speed. If it has been assembled with aftermarket parts 6000 is possible, but not much more.

The pontiac 455 that had ebrock performer rpm heads and a comp 230/239 duration XE274 cam made peak hp at 5200 rpm. There should be no need to twist it. Use the torque and gear it accordingly.

http://www.carcraft.com/techarticles/72278/index10.html

If u do twist that thing 7000, nasa will be calling you about things in low earth orbit.

 

The best way to determine redline is to start the car and let it idle until its warm. Then sit in the drivers seat and press the gas all the way to the floor (in park) and hold it there until the engine siezes. Take care to note the engine speed when it explodes. Then take this figure and subtract roughly 1000 RPMs.

Seriously, Every motor is different. I usually base it on rotating assembly, even though physically it is determined by the valvetrain. If you are using stock crank, rods then you shouldnt be spinning to 6500, even if it wants to.

 

for most pratical applications the red line is the point it stops making power. you can find that with a dyno, butt seat or other. most all engines will stop making power before reaching the physical limits of the parts.