i can only speak for a 426 and 440. both are fully built and both of us are getting better starts than most of the 450s. the 450's that have gone into the engine and put different cams and pistons we have trouble with but other than that we can hang with them if not beat them. my cosuins CT racing filly buit 440 is about the same as my baldwin 426 power wise, mine just revs quicker which give me the advantage. some people complain about head gasktes blowing but my cosuin has never had any trouble. there was also another 440 their, i dont know what all was done to it but my 426 was pulling it on the straights.
yfz450, TC, Leager, HIPER, PEP, K&K, LSR, TAG, AC, DENTON, VORTEX,DG
400ex tcs shocks (f) good condition $375
400ex JD Performance +2 swingarm for sale $500