68400BIRD
02-06-2010, 06:00 AM
I have a 1968 Firebird with a 400-400 combo. At this point everything is still original as in intake and heads. I have 450 pound springs and I see they offer 550 pound springs. Just checking to see if the 450's will work ok with my heavy front end.
BMR Tech
02-11-2010, 06:34 AM
Definitely go with the heavier springs. With the 450's, you'll be hitting the bumpstops often and their is just not enough rate for a car that you want to handle. When these first came out (back in the early 90's), the 450's used to be the only spring QA1 offered because people were only really building street cars, Pro Street cars and "hot rods" back then. Recently they introduced a few more rates for the Pro Coil setups to address the demands of modern day Pro Touring cars.