Its a weight transfer thing I guess, on the cornering. Given the IRS and FWD, the situation once control is lost is very different from what the Lark will throw at you if pushed too hard. Not only that, but its extremely easy to knock any corner of the suspension out of whack in a GTP compared to an A body if you bump something. One can't steer with the gas pedal on a FWD but a RWD sure can! My experience is all in driving warmed over stock junk though, you have the top notch soup-o-the-day parts on the big one.

Just my opinion, but consider the ballistics and construction of the two... or find a curvy road and try hanging with any random fullsize truck who lives at the other end of it. Theres not enough tire, nor room for much improvement. Now if you could put 11" wide rears and 9" fronts (tires) on a GTP, well it still wouldn't have that axle housing and gears holding down the rear. Part of the time I had my Skylark I ran the OE 14s and yes it handled like a GTP lol.

Have fun playing with the L67 it seems to be fairly rewarding once you get the hang of it, which I haven't. Just keep in mind that although it doesn't sound right, any mods and / or rarity of 40th GTP coupes add zero value, sale or insurance. Mods can drive sale price down, and heaven forbid if insurance pays you for it KBB is bible. Fair warning on that, these cars are hardly worth moped money. But theres fun to be had while all is well. Enjoy.