You are supposed to fill the sides with RTV, wet the pipe cleaners and stick it in. Its garbage don't do it. Get the rubber side seals, they're kind of a pain in the you know what to get in, so were the old fiber ones, this just requires a different technique since you can't tap these in. The don't make the fiber ones anymore because the secret ingredient to those is asbestos. Asbestos makes EVERYTHING work better but we can't have it anymore for obvious reasons.

Greg, have you considered making those side seals with something stiff in the middle so that they could be lubed up and tapped in like the old ones? I bought the side seals from a different source a while back (did use your gaskets for everything else though except my water pump), maybe yours install a little easier. The problem that I had was that mine wanted to slide up when sliding the retainer in. Had I had more time I could have glued them to the retainer, but just a thought I had.

PS everything Fel Pro sells seems to be garbage, buy Greg's gaskets or something from Victor and save yourself the aggravation. I was more than impressed with Greg's gaskets and will be using Superformance gaskets on anything I can in the future.