skysfallin, I have not started mine yet but just had to open it back up to measure the firewall. Mine measures 3 1/4 right in the top middle and on the left side it measured approx 3 3/8 and on the right side it measured 3 1/8". That is facing from the tail to the nose. That should be close to what yours is. I noticed also you put some triangle stock on the top of yours. I thinks this arf is one of the best built and awesome looks that I have purchased. I got my Dle 30 from tower like you did. I have got to get to putting this beauty together.