Which would be the best option for a 240SX install a 6 cyl. or just build up the 2.4 that's in it

 

Cheapest and most cost effective option would be to put in the 4-cyl SR20DET. You could build/turbo the KA but that's gonna cost a little more. As far as 6-cyl goes, if you are talking about a RB20DET (those are 6-cyl right) or the RB25 you are looking at MUCHO bucks there. Good luck, whatever you decide to do.

Jason

 

well if your gonna drop in a 6cylinder i would suggest going with one of the rb inline 6's. its expensive but in the end it would be worth it. the ka is also a good engine, with the money you would spend on that kinda swap you could have one hell of a ka built up, it all depends on what you want

 

Actually the RB20det can be had for about as much as an SR20 but you are right the RB25 will run you about 1000 bucks more. Just look here.
http://www.night7racing.com/rb20.html

 

the cheapest RB25 i have found is like...3500 haha

 

Well I'm no RB expert, but I thought there was quite a bit more time/money involved in an RB swap vs a SR swap.

Jason

 

hmm..well if u do it urself its basically the same. i might spend a lil more but thats it. BUT if u pay a shop to do it...then the installation cost will be more then a SR installation. roughly 2 grand for a RB20 swap, and for a SR swap its...1200-1500.