[2MCHPWR]

i don't know what i should do. my car is so nice, but i'm wanting to get the weight down, but i don't wanna mess up a sweet ride. the rx7's are 2800 lbs with the LS1.
i can sell my formula (heads/cam/12 bolt, 51k miles, ws6 hood, c5 brakes, recaros, koni's, etc) for $15k. buy a 93-95 rx7 roller for $5000, ls1 motor and t56 for $3000, and have hinson do the conversion for $7500.

[sgarnett]

I think the conversion is fairly well developed, and the bits you need cost way under $7.5K (not counting the donor drivetrain).

If I recall correctly, the LS1 drivetrain is actually a little lighter that the RX7TT drivetrain, so you actually save a little weight and improve weight distribution. The 3rd gen RX7 is already a great handling and fast car if you can keep it in the powerband with both turbos spooled. What it doesn't have is any bottom end torque.

The rotaries in general and probably the TT version in particular needs to be rebuilt fairly often. I think there's less to do when it does need a rebuild (primarily apex seals) but it's still going to be a pain. The LS1 should be a much longer lasting alternative, especially in such a light car.

Even if you leave the LS1 mostly stock, I would do something about oil control. Convert the PCV sysytem to use the LS6 valley cover, install a Canton pan if it will fit, and check the oil pickup for a damaged O-ring (see the TSB). I'd be tempted to at least install the LS6 conversion kit from Pace (may be a standard GM Performance kit - dunno).

A friend with an RX7TT keeps daydreaming about the same swap.