If your motor is sound i.e. not burning oil and quiet, a simple cam change and a set of headers should easily get 400 HP. Must find a good cam for a low comp motor though....
Take care, Rick 68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
