Ignition puzzlement

[johnnyringo]

A friend has a Dodge Dart with a slant six engine. 10 to 1 compression, solid lifter cam, long ram intake with a 450 CFM carb, Ignition is a Mopar magnetic pickup distributor, MSD AL6 box and MSD coil. Starts and idles fine. Road test engine runs to about 3500-4000 then will not rev further. Doesn't decelerate, doesn't miss. Any ideas?

[squirrel]

Valve springs

[Barry Donovan]

a map sensor version on an MSD digital box can carry that along..it may feel like a retard in part of the curve, but will own it for the rest of the way, air/fuel willing.
it is actually amazing to get that right. It will time it away from the spring float via ignition...automatically.

applies for any solid lift...even an old subaru boxer.

[anotheridiot]

there is a rev limiter on that box isn't there?

[johnnyringo]

Not valve springs and rev limiter was disconnected and set at 10,000.

[squirrel]

Have you checked the distributor pickup gap carefully, and make sure it is not moving?

[BigAL]

Have you checked fuel pressure at the time that it does it?

[BlueCuda340]

If the MSD has a rev limit chip remove it completely.

Having never wired up a 6al before I gotta ask this, there is no adjustment you need to make a for a six cylinder is there? I know my Digital 6+ box had a pot to set for that but I don't think a 6AL does.

[johnnyringo]

Fuel pressure and volume is good. Al box is set for 6 cyl. Waiting for a new distributor to arrive. Hope that is the fix!

[anotheridiot]

If the MSD has a rev limit chip remove it completely.

Having never wired up a 6al before I gotta ask this, there is no adjustment you need to make a for a six cylinder is there? I know my Digital 6+ box had a pot to set for that but I don't think a 6AL does.

6AL has looped wires that you cut to change from 8 to 6 to 4. Seems like the car was fine as it was wired already. so bent distributor shaft seems to make sense, I just thought there was a fault in the rev limit circuit that showed up.