just buy a 2.0 agg lump. any myths about them not revving are just untrue.
iv only a 268' newman and it pulls strong to 6.5k, but the torque drops off around 5.5. il try find my rr plot.
i got my 2.0 for £80 delivered and it was perfect. around £150 all in with gasketts, fluids. cheaper than a rebuild.
what pistons you using for the 2.1?