We have similar interest, I just replaced the firewall on my '33 Ford Tudor, which you know is a clone of your '34. I decided to go with a very un-traditional engine, and in doing so spent quite a few hours working on my firewall only to find in the end, that the factory firewall was not a good candidate for my extreme make-over. I originally purchased the front and rear floors, from Direct Sheet metal, and thought I would use my original fire-wall. After we found the original firewall would not allow the engine of choice to set in front of it, and look anything close to nice, we contacted Direct Sheet metal and I told him me dilemma. Since the engine wasn't the proverbial Chevy, they sent me a template to which I added some measurements, and re-sent back to them. The verdict was my engine closely matched the Chevy Big Block silhouette, but wasn't a sure thing. They were very honest with me, and did everything I ask them to. When I told them to not only order me the fire-wall, but also another front floor kickers and trany tunnel, this time one that would match my Big Block Fire-wall, they told me I would only have to pay for the fire-wall, I tried to pay to the other parts, since it was me that ordered the wrong things, but they insisted, and a few days later I received a box full of the parts requested. There support and service is number one in my book, they did everything I ask and more, I will always buy there products, they back them better then any other sheet metal supplier.
As a side note, the fire-wall which we knew was a stretch at best to fit, was a very nice piece, and was delivered in perfect condition. The fit to the old body or cowl area was excellant, and fit like a glove. Un-fortunately I had to modify the fire wall to fit the engine anyway. All though the fire wall was a great fit and an even better start then the stock piece, the engine we used had such big heads, that I ended up sectioning 4" from the fire-wall to get the proper fit. This has no bearing on Direct sheet-metal, since the fire-wall was sold as a Ford fire-wall for a Chevy Big Block not the Ford DOHC 32-valve 4.6L engine we used.