ive recently found a similar bike im trying to fix up
its a 1976 grand prix with just the frame,forks,bars,and crank
im having a hard time getting the crank arms off, being that old would they be one peice or are they just really stuck?
I can't imagine a Grand Grand Prix having a one piece crank, especially not in 1976. You can find the original catalogue specs for your bike HERE:
1976 Raleigh Grand Prix
I hope yours is one of those, because it is a Carlton built model as evidenced by the beautiful wraparound stays. If your crank is like the one in the picture, it is a cottered crank. To remove it you will need to unscrew the little nut on the end of the cotter pin and then BANG the cotter pin very assertively with a hammer. Repeat on other crank arm. Once you have the cotter pins out the crank arms should come right off with a little coaxing.
The only thing to keep in mind is that if you are doing this to go to a cotterless crankset, it is going to mean getting a newer cotterless bottom bracket spindle and/or replacing the bottom bracket entirely.
I may be giving you more info than you want, but if you are planning on going cotterless, save those BB cups and try to find a Raleigh cotterless spindle that will work. Unfortunately the threading on your era of Raleigh is proprietary, and a standard replacement BB won't work! The BB shell is threaded for 26 TPI, which only Raleigh used. Anyway if this is what you're trying to do, let me know and I'll give you as much info as I can.
Good luck.