Hi all 
Q1. Can a black top head assembly be fitted to a silver top block?
Q2. If so is there anything else I need to know about?
I have a black top head complete with 2.0l cams, and have been led to believe they can't be fitted to a silver top head. 
Q3. If I lighten the flywheel...how much should I take off?
I believe cylinders 2 & 3 are spaced slightly differently which is part of the reason why they're not interchangeable.
Dont think of doing the flywheel your self 
If you want lighter than 1.8 then look at the cvh with trigger wheel on the front pulley.
Or a steel flywheel.
Don't try to lighten the flywheel, is safety critical.
Get a silvertop 1.8 flywheel, they are light enough.
Do you want to sell the blacktop cams?
What's the weight of a 1.8 flywheel compared to the 2.0?
The 2.0 cams are in a blacktop 1.8. I was considering being lazy and changing heads on my 1.8 silvertop in my car.
It seems likely I will be swapping silver top for black top.
The heads are not interchangeable, the bore size is different and so the gasket rings would not line up correctly.
I would just swop engines, the black top is a better engine in my experience.
Paul.
I stripped my engine and replaced the head that was on my 1.8 silvertop zetec with another from a 2.0l silvertop (same cams as 130bhp escort gti). My
understanding and guidance was that the heads were interchangeable between the same type of engine (silvertop to silvertop, blacktop to blacktop), but
NOT cross matched. I've had my engine running on limp-home mode ok so far with the bike carbs and edis module.
From what I was told, it was mainly the intake system, cams and ECU that differentiated the 105/115/130brake models. The 105 brake had anintake pipe
over the rocker cover and a forward facing throttle body, the 115 & 130 engines had the air intake pipe to injection manifold running around the
side of the block (throttle body also faced upwards).
Unless someone can correct me on any of the above before I destroy my engine or get accused of misleading people?!?
quote:
Originally posted by coozer
Don't try to lighten the flywheel, is safety critical.
Get a silvertop 1.8 flywheel, they are light enough.
Do you want to sell the blacktop cams?
Its down to what the oe flywheel is made of and how its made but its not a diy job to shave a bit of.
Just youtube exploding fly wheel.
In a 7 the flywheel is pointing at your legs
[Edited on 26/4/09 by big_wasa]
Thanks for the advise I knew you guys would come up trumps 
The flywheel question was made for two reasons, I used to play about with flywheel weight in V8's when involved with competition 4x4 off roading
and realised the benefit of the right weight especially when linked to cam changes etc.
The other reason for my querie was as the result of talking to a guy who uses zetecs in his saloon car race car thingy! He was going on about people
in his type of racing who were taking huge amounts off flywheels...which in some cases resulted in exploding flywheels .
So I thought best ask those that know...you lot
It appears my next course of action is silver top to black top engine change.
Apart from the likes of the water rail, throttle bodies, exhaust manifold, alternator, starter etc. etc. which should be a straight bolt over, what is
there about this change I need to be aware of?
One thing I am confused about with the black top is that of working out how to run the fan belt so as to ensure the water pump rotates the correct
way. Is it clockwise as viewed from the front? (The alternator in my XT is offside and below the throttle bodies).
Am I missing the obvious or is there an idler pulley or something I need to source?
Cheers Steve
be carfull with a light flywheel,my mate races stock cars had a cupple go bang,the ones with holes in dont go near that normaly take to much materal
out ,get a solid on skimed by somone that knws what thay are doing.