i am doing a swap to a large streetported NA from a stock NA... im afraid that it will run too lean, and i dont want to ruin the new motor... the guy that built it said with a header and a freeded up intake i could make 260-280 HP... and i do have the header and intake upgrades. should i upgrade to 550's?

 

260-280hp on a n/a, and you said this is coming from the guy who built your motor, if so then he has no clue what he is talking about, 160-180 is more like it....

 

it makes 150 stock, u get more than 10hp from a good port... i have a friend with an unported NA making 175 rwhp