1971 cutlass s frame ?
 

I just got a cutlass S given to me by my cousin not really but long story, anyway im going to build a pro-touring car out of it. based on w30 442 clone. ive been reading the forums and i know that i need to box the frame so ive been looking at hpi and others but i like the extra bracing that their kit offers. im going to do full tubular a arms up front with coil over conversion all around tubular control arms in the rear with abc mini tub kit... i would like to be able to put some 345's on the rear. how does the fully boxed oem frames compare to the aftermarkets as far as rigidity? i think that maybe this only cost a fraction of the aftermarket frame

Welcome & Good Luck!

Sounds like you've got a plan together. There are a couple kits available from vendors that you'll find on this site. The question that you ask of ridgitity, i'd have to believe that the aftermarket chassis builders, with all of their engineering expertise, are building a far more ridgid unit than we can, with put together kits on 40 something year old frames. I outsourced my boxing plates on my chassis, but I did the rest of mine myself. Your absolutely correct about the cost, as I only have about $700.00 bucks in mine, from end to end, including the front extended travel coil over brackets.
Welcome to Lateral G!

http://www.speedtechperformance.com/...rod/prd398.htm

Here you go.
Plus we have ALL the other parts you are looking for