I used MSD mostly , Firecore is good also .
There is a huge difference in quality , Core quality & thickness , the ends also , insulation quality & thickness
What plugs are you using , just wondering the plug tips are smaller than normal , I hve not seen this problem in the past .
Try new Champion or Autolite plugs
My opinion is Multi port is the better option if you can handle the cost , virtually every new car is multiport not throttle body injection .
I built a system for a customer using components from various suppliers , 1200 CFM throttle body , SDSEFI computer , Bosch injectors , Walbro fuel pumps...
Removing the block will not change the ride at all .
You may have SS springs if it is sitting too high without the blocks ,
I would try better shocks first , double adjustable work best .
If it still is not what you want you can order different springs , the rear of the spring controls the...
You need to balance the front & rear diameter , Hotchkiss would match the rear & would be the best choice , or a matching diameter to the Hotchkiss bar