DavidC,
I have owned my first 400 since 1976 and it has been fitted with three different engines over those years. During the restoration I fitted a 100D2 engine , then 85A with 405 camshaft , 8.5 comp pistons and 100 head , I estimate about 100 - 105 bhp(I tried 3 SU , 3 Solex and 3 Weber on this engine)
The SU was the smoothest running but seemed to lack a little bit of power above 4000 rpm . For general touring between 60 - 80mph I suggest you stay with the SU.
Regarding the overdrive I dont think they are worth considering unless you plan to tour at 90 - 100mph . Many owners fit them to reduce engine revs and fuel consumption. They would have been better rebuilding & tuning their engines , rebuilding or replacing the distributor , getting the valve timing correct with an adjustable camshaft sprocket .
All 6 cylinder engines are designed to rev higher than modern engines , and will hapilly tour at 70 - 80 mph (3500 - 4000rpm) and achieve 28 - 30 mpg if in good condition.
The engine that is currently fitted in my 400 is a combination of parts , 100B2 block , 406 crank & rods , compression approx 9.0 to 1 , Sports Camshaft , 85C head modified to 6 inlet ports fitted with 3 twin throat Weber carbies with accelerator pumps . It his a strong engine, but can achieve 28 mpg on a long trip crusing at about 70 - 75 mph .
A STD 85A can do the same or better except it wont have the accelerating power.
I'm in the process of securing and rebuilding the original 85A engine for this car to get it back to original.
I suppose my recommendation is to build an engine suitable to your planned useage . No point in building a 170 bhp engine to tour at 60 mph.
GeoffD
|