BUICK/ROVER V8s CRANKS, BORES AND CAPACITIES

There are a number of crankshafts available for the 3.5 (215 cu.in.), early 3.9 and later 3.9 engines. Each will result in a different capacity. The following is a table made to resolve the confusion. Their are other setups out there as well.

First, here are the bores dealt with (with some Buick 215 exceptions listed in the second table);
 

ENGINE BORE
3.5 (215 cu.in) 88.9mm diam.
3.9 (early) 93.5 mm diam.
3.9 (later) 94 mm diam.
4.0 (all) 94 mm diam. N.B. The bore and stroke are the same as the later 3.9. The 4.0 designation was used merely to distinquish this variant from the earlier 3.9s. It is cross-bolted however,a very important feature. Yet it has proven to be the least reliable of the many versions of this engine from 1961-2004.  That being said, I have never heard of an engine failure on a Morgan because of it. 
4.6 94 mm diam.

and here is the resultant capacities with different crankshafts, piston and rod combinations;
 

These variations are not exhaustive but are more or less mainstream.
CRANKSHAFT 
STROKE		 3.5 (215)  3.9 Early
 3.9 LATER & 4.0s SOURCE
71.1mm 3528mm 3905mm 3947cc Factory
77mm - 4228mm 4278cc Factory 4.2
88.9 - - 4414cc Leyland P76
80mm - - 4444cc TVR,
Rimmer
82mm - - 4552cc Factory 4.6
86mm - - 4778cc J.E. 
Development 4.8
86.4mm * 4337
(with .02 oversize pistons)		 - 4844cc
(with .02 oversize pistons)		 Real Steel 4.9
86.4mm * 95.2mm bore - 4900cc Buick 300
94mm * 95.2mm bore - 5000cc TVR Power 5L
98mm *   95.2mm bore - 5600cc Buick 340 5.6

These programs will assist in understanding the effect of stroke and bore on capacity. They do not include the effect of piston and head combuston chamber shapes. As a general rule, which is true of this block, increasing the stroke will assist torque more than BHP and increasing the bore will increase bhp more than torque.   
* I do not recommend any of these engines  because of the tendency for block cracking and liner slippage unless top liners have been used.  

METRIC ENGINE CALCULATOR
Engine Data:
Bore:  mm 
Stroke: mm 
No Cylinders: 
Results:
Capacity:  litres 
c.c. 
cu. in.
IMPERIAL ENGINE CALCULATOR
Engine Data:
Bore:  inches 
Stroke: inches 
No Cylinders: 
Results:
Capacity:  litres 
c.c. 
cu. in.