post back the compression figures bad spark in the ignition system could also indicate bad earth point somewhere ! easy way to eliminate this is to use a spare jump lead and earth the engine and a good point on the chassis, its very well known for the coilpack to rot aswell which can cause this
if it is the bottom block it will be one of the gallaries which is difficult to tell with out some sort of x ray high precision equipment, (fookin expensive) basic inspection, water pump, any blockage in pipes, usual shit
1 : crack in the head 2: crack in the block 3: head gasket failure preassure test the head for cracks (machine shop £30 approx) if its not the head then suspect is the bottom block (hairline crack maybe) seen other vehicles with the same symptons and it was the block with a hairline crack good luck with getting it all sorted
start by eliminating each part in the ignition system one by one, also check the colour of your spark plugs ! also check the injectors, very difficult to give advice but pretty sure if you take it a local clued up mechanic he should be able to figure it out ! hope you get it sorted
conversion is not so bad to do on toyotas its the time it takes on the wiring side of things... mechanical is easy on the starlets the mechanical side of the conversion only takes a day and a half the wiring and dash removal is what zapps the time
just like you said, spoke to my mate at the breaker and they rarely come across them ! they bloody dont break !! only chance of as box coming if the car has had a bad smash and the casing is damaged, have told my mate keep a eye out and tell me when he gets one but who knows when ?
dont you have to bridge the two pins on the diagnostic socket to have it reset to 10 degrees ? not trying to throw a spanner in the mix but better to be safe then sorry ?
guessing you have fastened the head down to the block ? be patient and take it to the guy who said he can do it on the car ! i have done a few head bolts tht have been stripped before, this is just a cam/cap carrier so once it is repaired it should be fine !
going to mates breaker tommorow ! looking for yaris d4d boxes!! there is a pile of them in the back for export ! needle in a haystack but its worth the search !