I want to build a 1/48th scale Royal Navy FG1 phantom.
Is there a USN version that can be converted without major surgery?
Start with an F-4J and go from there. Longer front strut you’ll probably have to scratch.
If you can find them Hasegawa did a couple;
Revell reissued the Hasegawa kit a couple of years ago. Although boxed and with markings for an FGR.2, I think the parts for the FG.1 are still in there. I’d have to check that later. It’s mostly the catapult attachment points at the wingroots and different tailplanes. The extending nose gear leg was only ever extended at the catapult, so you can get away with not having that. Something Airfix cocked up on their 1/72. They only provide the extended leg in both the 1 and 2 kits. The 2 never had this feature.
If you’re struggling to find either kit, your only other option is the excellent Fujimi 1/72. This has also been boxed by Italeri recently. Might not be the scale you want, but it’s just as well detailed and the same quality as the bigger Hasegawa.
While trying to convert a J is possible, I’ve seen it done with Tamiya’s 1/32, it’s a LOT of work. The Spey engine was physically bigger than a J79 and needs the fuselage sides and intakes widening and deepening at the rear. I believe the wing was also broader, but I don’t have my references to hand right this second to check.