2.5/4 currently, but wanting to go lower ?'s

[my67chevytruck]

Hello,

we are currently running 2.5 ECE drop spindles with BBC springs on my sons '67 with a SBC. I spaced the fact that the parts truck was bbc. The rear is ECE 4" drop springs with shock relocators and adj. track bar. we are running 17x8 front and 17x9 rear rims.

I plan on installing some 2" drop front springs to bring it down some. My question was . should i install the 2" drop blocks i have, or go with 6" drop springs? was curious if any downside to running blocks, i know alot of ppl do though. any vibrations /known issues etc. to not run blocks. Will i be ok running the 4" spring, 2" drop block and reg. adj. trac bar, or would i need to upgrade to the super track bar?

Thanks.