You should get your hands on the BZR gearbox, it is a 6 spedd with a 4.6:1 final. It totally transforms the Levin. They turbo well also, the blacktop rods suck, but still good fro 6 to 8 psi. the silver top rods can take a fair beating.

She's in Perth and the car is long gone. The 6 speeds are a dime a dozen. The blacktop isn't as boost friendly in general due to almost no quench area, but it sure flows well NA. Keen to own a blacktop at some point in NA trim in something suitably light to really wake it up :-) Even with the 5 speed this thing didn't drop below 6k much on a "road course".

One of my rally engines is a 15:1 CR blacktop with 11.75mm of lift and 304 intake and 314 exhaust duration. Makes 253bhp she revs to 9500

Just spotted these old messages and would like to point out that I now have:

2 x J160 6 speed gearboxes
3 x Blacktop 4AGE engines
1 x KP60 Starlet

And a strong intent to combine the three pieces of tech into one monster :-)