With engine builds you tend to get what you pay for.
First of all you need to buy top quality parts including all new big-end bolts and main bearing cap studs.
Add in the best main & big-end shells, oil pump, camshaft, etc., etc.
Then there is the quality of the build itself and this is critical.
Of course you can get a builder who will not 'build' the engine so much as just 'assemble' it.
Building includes doing a comprehensive 'dummy build' after the initial machining is completed. Everything is measured and the block is then stripped for final machining of the block deck to bring the pistons right to the top. Each piston ring will have been checked for fitted gap, the crankshaft end float set to a close tolerance by, if necessary, linishing down a set of oversized crank thrust bearings, the crankshaft tested for free turning with the main bearing stud nuts torqued to 80% of correct figure. The big-end fit is checked the same way, all done individually.
After stripping and final machining, the block is chemically cleaned and the components assembled into it, together with new oil gallery plugs and water jacket core plugs.
After that the cam is accurately timed-in using either offset keys or a vernier sprocket.
Compression ratio is measured and combustion chamber volumes correct and set to the required value.
The block & head can then be finish painted.
Ignoring the gearbox build (that's extra), but allowing for assembling the engine onto the 'box, fitting and setting the flywheel & clutch, fitting the head and adjusting the valve clearances, fitting the distributor and static timing it, trial fitting the inlet manifold and in the case of a flowed head with enlarged ports, drilling and fitting the dowels to maintain alignment and all the other little jobs like fitting the engine mountings, that can easily take up to 35 hours labour. If paying a builder to do that you should allow around £35 to £40 per hour (some charge £50 per hour) so you see why it's not cheap to do it well.
That always makes me wonder as to what sort of quality you get from a cheaper build and it is why I stopped building engines for other people as everyone seemed to want it cheap which is not possible if it is 'right'.
So for an engine & gearbox, with, say, £1400 labour, £700 parts, £250 machining, £450 gearbox re-build, you are easily looking at £2800 for the complete job, maybe more if a new gear set is also fitted.
