Sorry Tony, I was thinking of your engine, of course the 610 manifold won't fit the 24V, must be the jet lag
I think we tried everything and nothing lined up (GTA, A610, Safrane etc)
On mine I'm probably retaining the original inlet manifold. It's not an ideal design though for installation in other vehicles. To start with the air intake is up against the bulkhead in a GTA. Also there are two vacuum operated flaps, one to balance the left and right plenums and one to open the seperate idle chamber.
If you run R25 injection/ECU etc as most conversions do then you can't control these properly and on the two cars I've seen they have been welded permanentley open which can't be ideal. I've just bought a new ECU with additional outputs so hope to be able to program it to control these.
To run a turbo(s) you would need a custom manifold or one from a venturi or similar. I'm hoping to make life easier with a centrifugal charger from Rotrex or Vortech.
The cost can soon escalate unless you are lucky sourcing the parts. As David (& Rupert) says it's often cheaper to purchase the whole car. If you have a turbo car to start with that also makes it cheaper as you don't need the extra fuel pump (and anti-surge tank). Also if you are willing to canabalise your existing engine that will save the expense of the crankcase and sump. The oil pickup also needs changing.
Typical costs:
24V engine £500
Custom manifolds & exhaust £500-1000 depending on spec/quality
ECU £500+ (unless you start with a turbo or canabalise a 25)
Fuel pump £100+
If you have an atmo you will need to cut out the spare wheel well to make room for the exhaust. Also you will need a lot of heat protection as you can't use any of the original heatshields.
To add a supercharger that's another £1000-£1500 plus a few hundred for a custom intercooler. Then there's all the custom plumbing and loads of other small headaches so you can see how it can all get expensive quite quickly.
& that's not forgetting all the labour costs if you're not going to do all the work yourself!