The new fuse bulkheads arrived from Vans yesterday. I have prepped them all and started assembling the fuse center section. The whole thing fits back together similar a jig-saw puzzle. You start with the rear seat back bulkhead, then the floor bottoms tie it all together with the rear spar bulkhead.
I'm also trying to match the important pass-through for controls and wiring and accessories (e.g. flaps) correctly as I go. I remember how difficult it was to trying to get the elevator tube to clear those aft-cockpit bulkheads after the fuse was all together, I really don't want to repeat that. The plans call for a hole that is far too small by at least half. I'm matching the parts as I replace.
I found the original builder added an extra bolt to the rear seatbelt attachments which causes rear bulkhead interference, far too much "cut-out". I removed the fourth (calls for three) bolt and minimal F-408A-L/R bulkhead cut-out.
Arrange the nose gear around the exhaust is tricky. RV-4 stock has a wide narrow slit. This may work well as the straight pipes can exist around the center where the gear reinforcements will be.
I'm contemplating using the RV-8-style (no-cheaks) nose.. I'm confident it can be done but causes changes that ripple up to the spar. The fuselage box is far wider. 33" vs 24". I would need to replace both front sheets with custom (3" taller), build a new wider F-402a,b,c and the belly sheet will not be stock anymore. It's being replaced anyway. I would fit a stock RV-8 cowl and RV-8A engine mount if I went this route.
If I stay true to the RV-4 nose, I will need to figure out a bottom attachment for the nose-gear... The rest would stay pretty stock.
Either way, the rudder pedals are going to be an issue as they attached to the firewall, which is now flat.