I have read bout both can someone point me to info where i can read the difference and the benefits or post a short summary of the pros and cons
A long block includes heads, a short block is without heads. What kind of motor are you looking for? Matt
With a Sti long block you will get the heads and cams which some say flow better...others say it is not much of a gain. From all the research I have done, you are better off getting new cams for your 2.0 heads and maybe some port and polish work on them. I mean doing the math...$4500-5000 for a used long block vs $1000-1500 for a new short block. That gives you at least $3k to play with for cams, all new seals, pistons, head work, etc. Just makes sense to me to go the short block route unless you plan on going with something that can control the AVCS feature of a long block.
IF you put STI cams in wrx heads they flow within 2% of sti heads, the only reason to get sti heads is because you want the avcs. Matt
AVCS is very nice to have. Ming I know you are all about streetability and driveability. The AVCS will help that tremendously. Contact KenieGenie on Naisoc....he's done all the testing and can point you to the light. There's a reason all the stock STi head cars are making close to the horsepower the cammed ones are. And they spool better too. Unless you are looking for more than 500 hp a longblock is better. I got my full longblock plus all the missing pieces (AVCS stuff, valve covers, and oil pan) all for $2600.
The cosworth cams aren't making the power they are supposed to. Cams are always a compromise, you don't get better spool and more top end power. Everybody wants a magic cam that does everything better....its not out there.