what is the ordered list of RPM limitations

[blandq]

A friend of mine just had a 383 stroked 350 built and is having difficulty setting his yellow/red-line limits. Considering common materials albeit Forged components and aluminum...no Titanium please, what is the ordered list of limiters?

I would guess Valve Float as #1.
Once addressed to exceed the desired RPM, stronger springs....what's next?

 

[larrylcoyle]

Two main issues with rpm limitations are valve spring issues and fuel delivery. They are easily noticed by what the car does in high gear. If the car stops pulling you can usually find one of them to be the problem. Now this assumes that all the other components are correct.

Larry Coyle

Cylinder Head Engineering, LLC

 

[blandq]

Agreed, I've experienced under-sized fuel supply in years past. I was looking to limit the dicussion to the mechanicals. For example I was day-dreaming a bit and thought; take a mild Ford 289 (short stroke), aluminum pistons, H-beam rods, forged crank and well balanced. That should be good to 7000+. Place stock heads on it and now your limited to 5500. now the day dreaming part; if I wanted 11000 RPM (hypo for illustration) let's assume we can get mechanicals to go that high....would flame front and spark timing be a limiting factor. Just considering the piston speed at those RPMs and a relatively constant flame front....it seems we'd never be able to burn that fuel

 

[larrylcoyle]

First you need parts designed to stand the piston speeds involved. Then you need a set of cylinder heads and intake manifold that will work together to that rpm. You only have a 3" stroke but a terrible rod length and very short deck height so you need to look at aftermarket blocks and longer rods.

Larry

Larry Coyle
Managing Partner
Cylinder Head Engineering, LLC
CNC Porting
De Soto, KS 66018

 

[blandq]

I get that...exotic materials for bottom-line strength for sure, Q. Short Stroke (Thats a plus) "but a terrible rod length" Dont understand the last statement.

Again, imagining we can get materials to go to the 1100 RPM, @ what point does the piston speed begin to push the flame front?

 

[imcjoek]

SBF block castings in the 5.0L range are known to split down the center with only moderate RPM (5500+) abuse. Your high RPM day dreaming is probably better spent elsewhere, unless you want to shell out for some kind of aftermarket block that is substantially beefed up (weight++, negating the advantage of having the little 289 in the first place?)

 

[larrylcoyle]

The only usuable part you have currently out of a stock 289 is the forged steel crank. Everything els is aftermarket. Pushing the flame front is a very minor problem (nil) with the aftermarket parts.



Larry Coyle
Managing Partner
Cylinder Head Engineering, LLC
CNC Porting
De Soto, KS 66018

 

[blandq]

Well, I hate to bust any bubbles but I currently run a 1964 289 block; forged Scat crank, H-beam Rods, JE Aluminum pistons, harden pushrods, Aluminum Heads, etc. etc. and my shift light goes off @ 6800 and rev limits @ 7200, I've never had an issue and run consistently in the high 11s. The build is 5 years old with at leaqst 20K street miles on it. To boot there is another 100HP NOS shot on top of the motor for an additional ~150ftlbs of Torque (lites off in 2nd gear, not off the line). Hell my converter stall is 2800...5500 is high middle of my torque band