Oldsub, thats what I was thinking but after some trial and error fitting I think I'm going to push the engine back into the firewall, so they're not that bad. I have the engine in place but the back of the heads are resting against the firewall and I still need another inch at least for the fan clearence with the radiator. I found a company that sells a replacement firewall with a 4" recess in it so that's an option. First I will do some trimming myself first and see what happens.Part of the fun of putting it together.