Here's what Henry said in another thread about his 2.45:
"I had a 69 911 T with matching numbers and wanted the most drivable engine but still wanted to retain the original engine.
I elected to build a 2.45 (70.4X 86). This is done by changing from the short stroke 66mm (2.0-2.2) non counter weighted crank to a 70.4 (2.4/2.7) counter weighted crank. Of course the rods are changed to match the crank.
The 86mm Ps & Cs are a biral cylinder (AA Performance) with a JE forged piston.
I chose a 9.5:1 compression ratio and a DC 40 (Mod "S") cam.
We ported the heads to 36mm and used Weber 40 mm carbs.
We added twin plug for the wow appeal but at 9.5:1 twin plugging is not necessary.
The engine produced good low end and 180 RWHP @6500 with more on tap as the engine breaks in.
The best thing about this configuration is that the cylinders slip in and the over all project is more or less a straight forward rebuild."
Here's the link to the other thread:
911 T 1969, need more power.
Tom