i have a 350 ci engine in my 70 chevelle and it has plenty of low end and take off power but seems to fall on its face around mid range throttle and above. it had a 2 speed powerglide and now has a 350 turbo tranny in it. i am using a holley 650 dbl pumper carb. any guess will be appreciated............... charlie

Stock fuel pump? Float level set? My guess would be fuel starvation.