sskianpour,
I am just finishing my Hellcat with a modified G23 which is bored to 34mm Looks like the G38 is 67 oz minus the muffler as compared to a G26 @ 53 oz. That’s almost an extra pound. I haven't weighed mine yet but I'm expecting it to be on the heavy-end as compared with other builds on this thread. That weight might be pushing it.
I should have an update in the next two weeks on how this one flies with the 34mm modified version. Reportedly it’s just under 4HP and after running mine I believe it. If you want more info on the upgrade you can find it here: http://www.davesmotors.com/store/product1300.html
Also, it’s much cheaper if you watch for it on ebay.
Good luck!