For me it was going from B1 original's to the PSO head along with a 55MM .900 lift cam...While I gained around 100hp thru out the RPM range it ran right by my 20yr old chassis capabilities...We have to take so much power out to be able to get down the track that we're still stuck in the high 4.70 to low .80's and need to be in the mid 60's...So now it looks like chassis prison and another lost season !!