Im on iOS 5 and want to downgrade to a version that has jailbreak, but i don't have the SHSH blobs.

1) You can't downgrade without SHSH. There's no way to do this presently, and I don't believe there ever will be.
2) Doesn't matter though! iOS 5.0.1 is jailbroken using redsn0w 0.9.10b3. You don't need to downgrade to jailbreak.

Hi im new to this forum and i was trying to downgrade my iphone 3gs the other day from 5.0.1 in the end i managed to downgrade to 4.3.5 through itunes dunno why it let me do it but it did and i have no idea what shsh blobs are you can always try it see if it works for you