Hi everyone! I'm new to the forum. Hope I'm on the right website for my needs.

I'll make this as a short as possible!

I traded a dirtbike for an 83 Z-28. The owner purchased a 1970's model 400 ci motor. He had the machine shop bore the motor over .030", which I have heard makes the motor a 406. Please correct me if I'm wrong.

According to him, the motor has 500 miles since rebuild. He said it has powerpack heads, hedman headers, roller rocker, big cam, edelbrock performer 750 carb w/ intake, holley fuel pressure regulator, hei distributor, pro street pulleys, etc.

When I go to accelerate, the car kind of chokes out if too much gas is given, and it simply does NOT have the power you would expect from a motor of that caliber. I haven't really torn on the car hard or anything, have put a few hundred miles on the motor. Like I say, I haven't gotten into it really hard at all, but it will hardly even burn tires in 1st gear without just losing power and launching. The motor seems VERY, VERY underpowered compared to other 400's I've ridden in that had far less done to them.

Someone told me that it shouldn't be that way at all, and that a calibration of the distributor, carb, and checking fuel flow could all help me immensely. Does this forum have any suggestions? I greatly appreciate it.