Second season on my 2056 with 9590 Raby cam and heads done by Len Hoffman. Stock L-jet injection.

When I run the car up to 5500-6000 rpm it cuts out like there is a revlimiter (which there isn't) or the valves are floating.

Could this be an issue of the L-jet injectors not supplying enough fuel at those conditions?

Do you have dual valve springs?

If not my car cuts out before 6k (due to valve float) with single springs.
But you can hear it coming on and it cuts out gradually.
If you have an adrupt cut out, it sounds electrical.

Is all of your ignition stock? Points or pertronix?
If points, have you replaced them (with the condensor) recently?
New coil or original?

Running pertronix
Coil is probably an original Bosch old definitely but don't know the history.


I only get the cut out when autoxing but that is the only time I really tach it out that far. I don,t really know if I would say I can feel it coming on it just gets to the those rpms and starts to cut out.

I don't have dual valve springs but when doing research for the build the general consensus was they weren't needed.

It could be your coil or basically any part of the electrical system going bad.
I have seen more distributor/rotor/cap problems than one would think.

There's the usual list of culprits that most racers carry as spares (and diagnostic tools):
New rotor(s)
New Cap
New plug wires
Timing light w/ tach (can put it on each plug wire 1 at a time)
spare pertronix
spare points (to rule out bad pertronix)
Coils are usually last on that list, but most have replaced the stock coil with a Bosch Blue or equivalent

Even down to a spare distributor.
If the bearings are going bad they will run inconsistently at high RPM.
Is there ANY side to side wiggle in the rotor shaft?

The distributor is pretty good as far as wiggle I went in and cleaned and relubed everything when I was tuning the engine and used the better of my two distributors.

Coil is a Bosch blue but I don't know how old. I have read some recommendations of switching to a pertronix or MSD don't know if that is just coming from the manufactures or resellers.

Fuel starvation?

Auto crossing can send all the fuel to one side of the tank.

L-jet does have a rev limiter, it's in one of the L-jet manuals that got limked a couple of years ago.

i'll try to find it.

when mine did this it was the pertronics, is the tach giving you weird readings as well?

Haven't noticed any weird signals in the tach.

There were revlimiting rotors but I don't have that in mine. Are you saying that there is one somewhere else?

We have a 2056 L-jet car here right now.

It sounds like the wiper on your AFM is going off the end of the board at WOT.
Add a few clicks of tension on the flapper spring, then retune the wiper position.
You'll probably have to re-connect a wideband O2 meter to get the wiper where it works best.

Sure its not valve float with stock springs?