Like the title says I have a 67 firebird with an Ls 408 stroker the bottom end was built by ATK with all K1 forged internals with a bullet racing cam and texas speed l92 cnc heads. PAC double valve springs the ignition is msd 6010 it's a 24 tooth reluctor. This is a brand new set up from carb to pan, even the fuel pump which is a pro star 300 fuel line and tank are new. The car makes awesome power up to 5500 to 6000 rpm then acts like it hits the rev limiter. I've already put a relay on the ignition box as well as a ground from the negative battery post to the box. I've even changed coil packs and tried a 25 thousands shorter push rod and it still does it! I'm pulling my hair out and need some suggestions, car has been dynoed and it did the same thing on the dyno 438 hp at 5700 rpm to the tire in thin montana air.

 

The 6010 has a built in 2 step rev limiter,, if your not using it on purpose, the default setting if I recall is up around 6000 rpm.. I'd plug in a computer to it and dum path settings..

I remember when everybody would get startled when the 6AL came out,,, it had like a 4500 rpm pill installed from the factory..

 

Stock box has the rev limiter set at 5500 RPM

Only way to change it is by hooking up a lap top, so if you have never had a lap top hooked up you have a 5500 RPM rev limit.

 

I don't have a pill in the box and I set the high rev limit at 7000 and the low for the trans brake at 3000

 

Check the two coil harnesses and make sure they are not both flipped over backwards. The purple wire goes to number one and the red wire goes to number two. The rest lay out accordingly. Something that is very easy to over look. And yes it will seem to run fine but will not rev past six G. I know its hard to believe. But it happens all the time.

 

Also make sure if your not using a map sensor to zero the graph or it could be pulling timing.

 

I checked all the wiring and it's plugged in as according to the instructions. I unplugged the map sensor last night but didn't check it on the laptop I'll do that when I get home and report back. Thanks for all the replies this has been quite frustrating I'm new to the LS game I've always been a sbc guy and almost went big block before deciding on trying the LS game.

 

There is no directions for the coil harnesses. They don't come with the 6010. So therefore there is not anything stated in the MSD directions for them. They are GM parts. Both coil harnesses are identical. Three wires in every plug are the same. One wire is a different color but both harnesses are the same. Just make sure the purple is on number one and the red on number seven on the drivers side. Then the passenger side is the opposite. Red goes to number two and purple goes to number 8. Lots of people miss this. Just to make sure.