The guy who had my 78 elky before me put these fat tires on the back and i think it is contributing to a acceleration problem.

When i am cruising and i put the pedal to the floor there is a delayed acceleration. does the forward agle of the car do to the big tires have anything to do with this?

No

Look for a vacuum leak under the hood.

Like he said.. Might be a vacuum leak or many other things.. Id take a look @ the carb first personally ;/ Float level might be off or jets/rods

If it has the stock air cleaner on it , look inside the snorkel end and make sure the hot air delivery door is down cause it will cut off air to the carb if it is not retracting down.

Running Rich? Timing off?
~just the problems i had with mine with a similar situation.

The tires wouldn't cause this unless of course they're flat. :lol: Definately sounds like a vacuum leak.

Could be that the accelerator pump is bad or needs adjustment. Usually there are three settings for the accelerator pump top, middle and bottom if it is not on the top then move it one position higher and drive it see if that fixed the situation or if it got better.

If nothing changed take the top off the carb and look at the leather pump. see if it is fitting the tube its in complete and drag the sides just a bit going down. If it is fine then look for a vacuum leak. If its a Q-Jet then one important issue is "How old is it?"

Lots of time the carb will need to be kitted, I'd say every ten years at a maximum. Around the throttle levers are some plastic bushings they will cause a vacuum leak if they are worn. Also, be cautious about just how tight you slam down on the wing nut that holds the breather. With a lot of carbs the center section is prety thin, they will warp with too much tension on the All-thread going into the bottom. You end up pulling the bottom plates out of line and causing a vacuum leak that way.

I have an issue with a Vacuum "T" coming loose on the intake.

Just some things I have run up against. But it sounds like an accelerator pump, that is where I would start its the easiest to see.

Elky Pete is correct. Hesitation is most likely caused by an accelerator pump problem.