Holley 4160 318LA Bog Under Load

First, I'm sorry if I've posted this in the wrong place. Now, down to business:
My engine revs fine and is excellently responsive in neutral, but anytime I step on the throttle on the road it bogs down before taking off. I've read everything that Holley has to say about the problem and have tried larger and smaller discharge nozzles (their recommendation), as well as having made sure my accelerator pump is set correctly, with no change. So far there has always been one more thing to try in order to rectify the problem, but now I'm at a loss. Also, it seems like if I don't continue to press the throttle a little further when it starts to bog, then the engine RPM will continue to increase with negligible acceleration. Just not sure where to go from here, and I figured it was time to use a lifeline and ask the good folks at FABO. I appreciate any suggestions and apologise for any typos as I wrote this up on my phone.
I have a '78 318LA with TTi Shorties, off-brand HEI-style distributor, and a Holley 4160-1850c carb.

Before tuning the carburetor, it is imperative to get the timing sorted out first. Where is your initial and total timing?

Also, it you have been watching Holley videos, you know there is an order to tuning a Holley carburetor and if you miss one step, it nullifies the next. So it's important to follow the tuning steps in order, or all is for naught.

And if you got a 6.7 starter gear, with a stock TC, and a fast secondary opening rate, there will be no helping that combo, until you're out to well past 20mph, or probably closer to 30mph. A 600 is just too much for a LC teener saddled with stock everything. Now with 4.30s and a 2.74 low, I can tell you that a Thermoquad is not too big!And blowing out dual 3"s to the back bumper is pure music!
I myself, would consider 3.55s, a 2.74low, and a 2400TC, as minimum for a low compression teener; pulling 3600pounds. This will take secondaries real early.And real early is where the fun is.

So what's your combo?

as RRR said check your timing...initial timing is very important...

do you know what color spring you have in the vacuum can on the carb?

also get the power valve correct before trying to tune the thing.
i put a 600 holley on my truck with a 318 (stock, 18" vacuum at idle), i put it to baseline (68 jets i think) and had to jet up to 72 before it stopped lean backfiring.
had to put an 8.5 power valve in it to get the part throttle transition working well.
i ended up jetting up again to 74, and the fuel mileage got much better.