I can set the 4 bar in my Hemi Duster either as a parallel 4- bar or configured as a 4-bar / 36" bars w/ about a 5" instant center.
IMHO....the parallel is more of a street friendly set up....with the bars parallel, there is virtually no bind or pinion angle chage thru up/down rear movement.
On acceleration , the rear tends to sucks the car down.....I'm from the school for best launch, you do not want the rear sucking down...or raising / pushing up. You want the rear staying neutral and all energy moving the car forward. the parallel set up wil also roll thru a corner better......no bind. A plus for cornering.....no big deal on drag cars
Most triagulated 4-bars do a nice job of locating the rear end, but they do not have the advantage of a 4-bar with the correct instant center. The lower bars locate....the upper bars transfer /apply the energy to the frame.
I see a lot of parallel 4 -bars in street rods, hot rods with low to mid hp....but never in a competitive race car with 900 plus hp.
Mine falls into the "limited" street use (not daily driver) and after running both configurations, I opt to leave it in the 4-bar /non parallel package.
