Is there anyway to tell if an engine is

open deck,

semi closed deck or

fully closed deck?

And which one would you recommend?

I've also seen some with coil packs and ht leads, does this make much of a difference?

I haven't heard to good things about the engines with ht leads but I'm new to scooby's

 

Early classics used coil on plugs (one coil for each plug so no plug leads). These are brittle and tend to break down and fail a lot.

Later classics used a single coil pack on top of the engine which has conventional plug leads. These don't tend to go wrong however if you want big power there are some vague arguments to suggest single coils are better.

Newage cars went back to the single coils with one on each plug and no leads. However they are a newer design which is far more reliable then the early classic ones.

It is possible to chop and change between different coil setups with a bit of DIY loom making.

Not many cars came with closed deck blocks. You can tell with the heads off the block as you can see how much metal is around the bores. With the engine assembled I think the closed decks have some hatch marks on the block that give it away.

Closed semi and open are all fine in standard form and it doesn't really matter what you have at standard power. If you want to start really increasing boost with bigger turbos then semi is stronger then open and closed is the strongest. The reason for this is the increased amount of metal around the bores which supports them better. If for example you only want sub 350bhp an open deck will handle that fine with the right supporting mods.