The texas chunk shuffle was reintroduced to blues players by SRV. I'm Cryin and particularly Pride And Joy are prime examples of putting a percussive sound in as the upbeat. It works pretty well in other styles so it is worth knowing. Since it is percussive, the timing is crucial. Start out slowly with this and build up speed.
The right hand does a palm mute right behind the upstroke so the strings ring briefly before being muted. of course, your not actually using your palm. Your rolling your hand on the upstroke so that the edge of your hand on the baby finger side naturally comes into contact with the strings right after the upstroke.
I have pared this down to the basics. Normally there would be all kinds of embellishments added for interest. I have left one hammer on in there just to give you a taste of some of the possibilities. It is a tough hammer on for an acoustic so you can either move the 4 back and remove the three all together or pick the 3 and the four as 16th notes before the next upstroke.
While this sounds ok with an acoustic, an electric with some overdrive fattens it up nicely.
The B7 and A7 are a simple blues strum with a muted upstroke at the end. Key of E. Hope you have fun with it.
Sorry for the midi. Still working on getting my recording software back up.