power brake swap ?

[srv8800]

i'm in the middle of a power brake swap on my '72 lwb pu. the booster is reman and i got the brackets and pushrod off of a 1/2 ton '69 pu. the brackets and booster are installed with a new mc on the way. my question is about the pushrod. the length it was when i got it was way too short. it has to be extended to the very last thread to reach. i don't think that's safe. the brake pedal should be resting on the rubber bushing right? i can get it to reach if i install it with the brake pedal up off the bushing a little bit but i don't think that's how it goes. am i doing something wrong? thanks alot