Lol, these types of things happen when you do not think about the combo working together. Put your same parts in someone elses hands and they make double what you are.

If you are going with big wheels then it needs to be geared correctly. Real stall and real cam. My 6l combo with 4.88s and 4k stall would run about anyone.

 

i had similar issues, plus a bunch of big heavy slow parts (11.5 gear axle, 35 inch tires etc) but long tubes made a HUGE difference for me.