Dear Plheure2,
Thanks for your question, actually it was mostly because I had to chop off all the bottom of the section where the engines go and rebuild and rescribed all over,the cutting, bending and applying of aluminum sheet for the top of the nacels also was a little bit tricky.
This was my second prototype and compared to the Revell 1/32 XF4U-1 (you should find it on these pages too) it took about the same on the research, planing and scratch building, someone out there can probably finish it sooner but I am new to all this and altogether it took me about 7 months.
Thanks for looking!
Jerry