I have a 408 stroker 68 barracuda I race just for time slips. It will run high 6.90's at 98 in the 1/8th. I am having trouble with it having high RPM crap out ( I shift at 5800). I am running a carter electric fuel pump, 3/8 line and a 750 Holley double pumper. I don't believe it is gas related. It doesn't die out or completely lay down. It will intermittently crap out about half track sometimes and then the next time it will run ok. I have a mopar electronic dist. system with a chrome box and good stock type wires. What is a good budget ignition system for a small block? Can I use the mopar distributor with a MSD type ignition unit or do I need the whole set of box, dist, coil? Also which of the big aftermarket HEI dist. clear the fire wall on a small block A body? Thanks for your experience.

I cant help you much but I can tell you I run the MP orange ECU box with an old Accel super coil and I have never had any trouble with it running in the 10's shifting around 6000 to 6200. My brother used a Mopar dist with MSD and we have a stock Mopar electronic dist on my sons Dart with MSD that I just recurved and it has run good on his 11 second Dart. Intermittant problems like that can be a hassle. You might just try swapping out a few easy parts first like the coil and ECU as I know many still run the chrome box with good luck. Ron

Check the reluctor air gap, and upper distributor bushing for wear. What coil and ballast resistor are you using. Chrome box should be fine for well above your rpm limit. Make sure you have good power going to your coil and chrome box.

MSD 6A will work with your stock distributor, as will most other ignition boxes.
I found that a 2-wire trailer connector had the same configuration as the stock distributor, so hooked the proper end up to the MSD. Then follow the wiring diagram on about a million websites. Basically a big red and a big black wire directly to the battery, the small red wire gets fed electricity from input side of the ballast resistor, make sure you wire it up so it gets power in both Start and Run. Ballast resistor and everything to the chrome box can go. There are two wires left, they connect directly to the coil. I am using a chrome Jacobs coil that has to be 30 years old, about any coil will work, but I'd suggest either the coil you have or else a coil from a Ford TFI ignition, like you'd find under the hood of a '89 Mustang or Taurus. It's a nice solid coil, can be mounted any orientation. Or you could spend dollars on a fancier coil.

My MSD was used and cost around $40.00.

R.

first I'd pin it down to fuel or ign for sure. As a general rule if the fuel system is borderline it will start to act up in high gear cuz it takes awhile for the system to get starved but that generalization might be out the window in a short eighth mile run. For ign I'd check reluctor gap as said and rotor phasing and rotor gap to cap terminals (.015" is ideal) and want good plug wires and clean plugs. No vac adv I am assuming. Holler how it turns out. EDIT I would check the psi from a line T'd AT the carb inlet during the run, can run a vac gauge taped on the windshield (most round ones have a psi scale but not sure how accurate they are but it'd be a start)

Due to apparent randomness of failure(s), I would set up as a trial, wiring to ignition to come directly off the battery, thereby bypassing all ignition switch and ignition harness and associated connectors under dash and firewall.

This simple trial would give you insight as to if failures if they indeed are ignition related, are in car's wiring system or more closely a failure at distributor, ballast(if you are running such), or coil themselves.

Poorly performing ignition wiring(those miserable Molex connectors being suspect 1) has oft been found to have been root cause of a wealth of mysterious performance gremlins.

If you don't already have them, run a ground wire to each head, and from the head to the frame, and the battery. Most electrical issues are due to bad grounds. Don't trust the head bolts to give you a good enough ground.