bro, I read all the N/A E-Series Engine Discussions post about 4efe anf 5efe. but still confused what I need to change if I want to increase bhp of a 4efe engine as same as 5efe engine. If I buy 5efe engine head, block, piston and than use other things from my current 4efe engine it will increase my bhp? or i have to change other things? give me a complete suggestion please. If possible give me a list. Thanks for any help.