I recdntly test drove a 1977 with a 351M and when I put it to the floor it hesitated and then began to accelerate. What could cause this?

 

Many things;

Needs a tune-up
vacuum leak
carb problems

 

Sounds like a classic example of a bad accelerator pump. Could be other things. But that would be my first guess.

 

I have a similar problem with my 95 5.8 TBI with KN and TB spacer. Great acceleration when cruising at speed (60-75 mph) but a big dump from a standing start... I'll be doing the plugs, wires, etc. this weekend and am looking for other ideas to cure this.

Thanks.

 

since i just had a similar problem with my truck, check the vaccum advance...worked wonders for me.

1977 F250 460
C6 Hedman Headers
Dual 40 series
edelbrock performer
holley 4160
msd 6a and blaster coil