Ok my 85 gsl
Stripped and rebuilt nikki w/mech secondaries
Intake has the shutter valve removed.
Stripped of all emissions/rat nest
Direct fire ignition/Ngk plugs
Factory exhaust with no cats and a free flowing muffler. (Need header yet)
Car seems to pull nice in lower rpms. Seems weak in the higher r's. I can pull to 60 ok but it seems like after that it doesn't pull as hard as it should? And doesn't get over 100 for crap. Maybe I need bigger carb jets? Just before it was parked for winter the msd box took a **** so I just parked it for winter. Put new box in now and runs perfect but just seems slower than last summer. I don't know if that has anything to do with it?

 

Bigger jets are useful only with a long primary exhaust, near as I can tell. I drilled primary jets to 105 with a short primary exhaust, and the benefit is negligible.
Have you changed fuel filters?

 

I'm curious about the answer to this also. I'm running pretty much the same setup on my 83 GSL (with RB streetport exhaust and half bridge engine) Nikki is maxed out in terms of venturi size and jets. I noticed a drop in power when I went direct fire and she struggled to climb past 6500 rpm. Without the know how or ability to check the MSD 6A box, I opted to go back to the factory ignition. There's some improvement , but not enough. Even advanced the timing to 20 deg and she feels and idles better, but not as powerful as she did before the mods.
I'm looking around for a 48 IDA Weber and 4 port manifold to see if it makes a big difference.

 

Yup new filter last week. Something just isn't right. It seemed like it was starving for fuel up top sometimes but when I ran my dfi coils in series vs parallel it didn't do it anymore. So I'm thinking ignition issues? Maybe this box sucks? I figured they either work or don't? Can they be week?

 

i was going to say, you are probably out of fuel pump, but its also possible you're running out of ignition too.

you might try running the coils directly from the alternator instead of the normal source, as 14v will be more powerful than 12v

 

I have the msd hot wire straight to the battery. I could try to go off alternator. Last summer the dfi was really noticeable. Now with the new box it isn't.
One thing I noticed also in the dizzy. I had the cap of running it with the dfi and when I rev it the trailing vacuum advance really seemed to move a lot but the leading barely moved. Is that normal?

 

the vacuum advances are stamped with the amount they advance; leading and trailing are different, and then they also vary with the year.

they have it setup so it runs a 15 degree timing split at idle, and WOT, but at cruise its more like 5.

oh if you have an MSD, its probably fuel

 

Well next move is a bigger fuel pump.

 

Are you sure the secondaries are opening all the way? Check your linkage. You shouldnt need secondaries at all or a bigger fuel pump to achieve 6500 rpm or 100mph though... if your fuel volume test fine, compression check?

 

I'll have to check the 4 barrels. Compressions 90-95 psi

 

Started feeling like it was starving for fuel again. I'm gona have to try a better fuel pump.