Installing Rod Bolts

Went to install some new ARP rod bolts in my current project this weekend.
I knocked out the old ones, no problem.
Took the new ones, added some molley lub provided by ARP, tapped lightly to get them started, used a C-clamp with a 3/8" socket and tried to press them in, got a little bit but not enough for all the effort, I was trying to get enough to stick out so I could use the nuts to pull them the rest of the way down. I really didn't have enough thread showing to comfortably pull on them hard enough without worrying about tearing up a thread on the bolt.

Pistons are on the RODS, I didn't have enough room to use a hammer and not hit the skirt of the piston.

Does anyone have a way to do this, the C-Clamp thing just isn't working.