Hi Jesse, The 290HP 455 also known as the SD, is a little stiff at 350, but should run well with up to date parts that we can run now. If you can put a good trans and converter behind it , I think it can be at least a 1 to 1.10 under car. The 255 hp is the same deal, I think this might be the better of the 2 combos. It has almost the same compression, Heads are not nearly as good or big volume wise as the SD but it is 35 less HP. The parts will be cheaper to come by, and I think when you are done this can be a 1.15 to 1.25 under car with some hard work. Both combo's can be good and fun to work with.
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Originally Posted by Jesse Knapp
How competitive is this engine today? Looking at both the 250 hp. and 290hp. SD.in a Firebird. It's natural classes can be E, F, G, and H. Used to run in I yrs. ago. Wondering how quick it can be today with the good stuff. Appreciate any help.
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