I don't know what vehicle the 235 is in, but usually it cost just as much or more to swap in a later engine than it does to rebuild a 235.
The bellhousing, tranny, motor mounts, tranny x-member, driveshaft, wiring, cooling system and linkages are different between a 235 and any later model engine, 6 or 8 cyl.
You may be able to get away with an in-frame rebuild, assuming there is no serious damage/wear to a part you can't fix in-car.
Look for excessive cylinder taper, cylinder scoring or gouges from old piston rings, cylinder-to-piston skirt clearance, or out of round cylinders. Check the crank throws for out-of-round journals, scars or gouges, 'bluing' from overheating, or flat spots from loose bearing inserts. Check the crank end-play for worn main thrust bearing. More than .010" indicates a main bearing problem. (trust me on this one)
You can see the cam bearings from under the car with the pan, rods, and camshaft removed. Look for scoring, marrs, or copper showing through the bearing material. Check the #1 cam bearing for strange wear patterns from timing gear runout.
If re-using the pistons, check for impact damage from valves. Any moderate or serious impact damage on any piston requires replacement of all 6 pistons. Clean the pistons of all carbon, especially in all ring grooves. Check new rings for proper side fitment and depth in ring grooves. Check ring end-gap, to prevent broken rings. Hone cylinders with a bottle-brush style hone of about 250 grit.
Have all 6 rods checked for out-of round big ends, straightness and proper pinch-clamp bolt torque.
Cost for in-frame rebuild:
rod bearings 40
gasket set 100
oil pump 45
rings 30
pushrods 35
head work 300
machine shop work (rod inspection etc) 50-100
So the lowball cost comes in at about $650 if there is nothing else wrong. This assumes that the manifolds, carb, water pump, fuel pump,cam, gears, lifters, pistons, distributor, rocker arm assembly, rods, main bearings, cam bearings, cylinders, crank, etc are still usable. Also check your freeze plugs for seepage and your cooling and oiling passages in block for sludge or blockages.
Be prepared to buy tools, hoses, lines, filters, gizmos and whatzits that you didn't know you needed.
Sheesh, yet another novel...
Chip
