is there cold air intake for '88 blazer s-10?if so where can i find one..? also.. will just a k&n air filter really help to gain hp and greater sound ?

yes K&N are great. as far as I know they dont make cold air intakes for our blazers, pre 94. If you find one let me know I've looked everywhere.

http://www.knfilters.com/search/product.aspx?Prod=57-3028

That's the closest I could find from K&N

http://www.car-stuff.com/performance/quote.php?make=5&year=1991&model=29&brand=93&part_name=15&category=

Volant cold air for 4.3L

how much hp can i expect from the volant cold air intake and is it worth it? or would i be better of going with the k&n

http://www.volantperformance.com/pdetail.asp?ID=7

That's a more detailed description of the Volant

http://www.volantperformance.com/faqs.asp?ParentID=14&ItemID=11

That's the closest I came to answering your question