I'm am doing a frame off resto on my 66 Chevelle SS and am planing on a 550hp 454 BB (give or take a few pony's). I am going to run slicks (11 inch). For suspension rear sway bar, air bags and poly bushings. I don't think I will ever get the car to hook hard??? Okay ill get to the point I don't want to run a roll cage (sleeper), do I need to box my frame or is it OK as is? What do you people think?

Thanks

Hot66ss

Boxing the frame will slightly increase the rigidity but hardtop Chevelles are already reasonably stiff. I don't think that it would be worth your time. Just my opinion.

A couple of suggestions:
- Pick up a convertible frame
- Install stiff body mounts with bolts at all locations. I'm not able to verify from the factory assembly manual but your car probably did not have a #1 body mount and no bolts at 3, 5, & 6. If you tie the frame & body tightly together, torsional stiffness will be improved.

the convertable and wagoon had the same boxed frame, you might can find a wagoon easier and cheaper. hotchkis perf has a nice '65 with all their goodies, might give them a call. there was a guy in car craft awhile back who installed a tube frame inside his stock frame. i thought that was pretty cool albeit expensive.

I'm no drag racing expert but I do have a 67 hard top and had a 66 4 door. Is the frame solid with no rust? You may want to just box certain sections by welding on some plate steel. I'd build the car first and see if it twists, then add bracing as required. Do you have the SS braces in place?

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I do have the SS reinforcements in place and the frame is straight and rust free. I don't want to change the frame because it is a # matching car. I am going to have the frame powder coated so I don't want to put in the engine and see if it bends. Just wanted to know if there is any PREVENTIVE measures? Also worried about body flex.