I take it you're referring to the correct type of 90 deg rotating retracts correct ?
If so, I'd recommend the H9 retracts for the p-40/ hellcat available through Horizon...the price is just right and most people have very few complaints with those.
VQ also makes an affordable set that can also come with oleo struts...
The only problem with mechanicals for this bird are that of course, you'll need to add a 90deg bellcrank, and that could be tricky.
on the onther-hand, since you'll already have to open the wing (like I did), I guess it wouldn't be that big of a deal.
God luck with that and please post pics for all to see when you're done.
P.S. I ordered the H9 wing blisters and wheel wells for this plane, but never used them.. i'll sell them to you at a super discount if you'd like to use them.
