I have decided 100%, for sure, I am going to buy a used block, probably a 454 block- and going to build it up and drop it in the blazer. My question now is- what heads to look for and how much can i bore it? What kind of max stroke can i get without clearancing? What is the biggest CI i can pull out of it safely and not have to pay for clearancing? Any certain #s i should look for? a 4-bolt main is best right? i don't know big blocks all the well yet, but hopefully next year i'll have one sitting under the hood and the whole neighborhood will be well aquainted with a 3" straight piped BBC /forums/images/graemlins/grin.gif note- i'm looking to spend $5-700 on some new or slightly used aluminum heads, then port and polish them.