Big Vern, i have to dissagree with you in respects to doing a complete rebuild of a CVH engine for £150. As I will be doing one for that exact budget 

. Heres a list of bits i'll be getting for it:
•	Engine degreaser - £5
•	Engine paint - £6
•	Piston rings - £32.50
•	Big end bearings - £17.50
•	Head gasket set - £30.50
•	Head skim - £20
•	Oil - £20
•	Main bearings
•	Spark Plugs - £10
•	Thermostat - £5
•	Oil filter - £5
•	Timing Belt - £10
•	Sump Gasket - £8.46
•	Core Plug Set - £7.50
•	Air Filter - £10
•	HT Leads - £12
•	Water Pump - £10
Total = £150
As you can see it's a pretty extensive list, including getting the head skimmed. I am yet to decide if i need to buy main bearings as mine don't seem  to need replacing, but it depends how much money i have at the time of rebuilding it all. 
At the end of it i'll have a fully rebuilt 1.8 CVH engine, which i know will work since it's all be checked out and rebuilt by myself and should last some time. Where as if you spend £150 on an old zetec engine, you dont know the condition of it and you are still going to have to replace a lot of bits on it, so it will end up costing you more. I myself have been wanting to bin the CVH and buy a zetec but the financial implications of it outweighed the gains if you ask me, if you ask me theres more fun to be had in a slightly lower powered car when you are an inexperienced drive 

.