I have a #2 condition 1972 chevelle Malibu 2Dr. Sport coupe with 36500 original miles. It has a beefed up 307 ie. cam, intake, carb. and 3 on the tree manual. I drive it about 300 miles a year and store it in the winters. Starting next summer I want to build a 425hp, 450ft. lbs. 383 and put in a Tremec 5spd. I already have a 8.2" with 3.73 gears and a locker. I also want to put a functioning Cowl hood and Bucket/ counsel combo. Am I ruining a great car? I had it appraised for 19400 for Insurance purposes. I know it isn't worth that much if I were to sell it cause it isn't a SS. I inherited it and I never want to sell it anyways. I don't want to race it, but I want to beat those rice rockets once in a while, and take it to the track once a summer. Is this going to ruin a classic? I have all the original engine parts and would rebuild the stock back to original, throw it and the tranny in storage.