Missing/Bogging Down

My '78 L48 is missing/bogging down during acceleration. It began with a very minor "miss" during acceleration a couple of months ago, but it has now developed to a really bogging down when I attempt to accelerate or climb hills. It is still idling well and it can maintain highway speeds with out any sign of missing.

I am hopeful that it is just a carburation problem. I plan to take it to Jody Gregg's Speedhound performance in Loganville, GA for a good tune up-but I would like to have some of the C3VR members ideas on what might be causing this so that I do not go in blind.

Also, are there any other members who have had experience with Jody Gregg/Speedhound Performance? I have seen him quoted several times in Vette mags, but that does not necessarily mean that runs a reliable shop.
Any comments/ideas much appreciated.

Could be a weak ignition as well.

HI I HAD THE SAME PROBLEM WITH MY 74 COUPE . MINE WAS DOING THE SAME EXACT THING . TURNED OUT TO BE THE TIMING CHAIN / GEARS .THEY WERE VERY SLOPPY . GM USED NYLON WHEN MAKING THE GEAR TEETH BUT I DONT KNOW IF THEY DID FOR YOUR YEAR . BUT SOMETHING TO LOOK INTO GOODLUCK BADWILLIE 74 COUPE & 2000 CONVERTIBLE .

it might be a fuel pick up problem,pop the gas cap and take a flash lite and look straight down. there is a sock fillter at the end of the sender-fuel pickup tube, it might be collasped or clogged.

Mine had a miss and was bogging down also. The miss came from a lose intake lifter on number 3 cylinder and the bogging down got fixed by re-jetting the carb. Now it runs great.

Thanks for all the help. I have decided to take it in for a complete tune up including ignition and carbuerator clean/rebuild. If this doesnt resolve it will at least rule out a lot of options. I will let you know what I find.