tubular k frames

74demon said
what is the weight difference? im doing a fiberglass front end and deck lid full int 440 stroked

That depends on what kit you get and options like a sway bar or rack and pinion.

The one Mancini sells made buy CAP uses the stock T bars and takes off around 50 pounds or so.

The AlterK around 100-120 pounds and uses coilovers.

The one from Magnumforce clames 100-150 pounds.

A mustang two style front end would be the lightest but not the best choice for a street car to be running. It would be more for a drag only car.