Header, Intake, & Exhaust - magnaflow installation trouble

so im having a little difficulty installing the magnaflow cat i picked up for my car... the flange that bolts up to the header is set back more than my test pipe was so i need to compress the springs more to get the bolt to go through the header. any body have a good suggestion for compressing the springs? i've tried to channel lock it and compress the springs with a c clamp, neither was successful. should i just go out tomorrow and buy some longer bolts?

i had the same problem putting on my magnaflow exhaust, what i did was had my brother come out and he could use both his arms to compress the springs compared to my one. you could have someone help you out or longer bolts wouldnt hurt either