24v V6 to Alfa 75 conversion.

[poohbah]

In reality it is probably cheaper to buy one that someone else has already converted, given they will be the ones to have suffered the financial and emotional pain. 

If you can find one of course.

[Duk]

Go for a decent programmable computer straight off the bat.
Peak power numbers probably won't improve SFA compared to the late model 24V ECU, but the installation will be a lot easier and will allow you to tune for any engine changes in the future.
Mutilating a wiring loom and getting the MAF sensor to fit in the available space compromises too many things.
Spending money to basically lock yourself into a factory ECU that can be retuned, but at great expense and potential compromise (mad camshafts and MAF sensors don't really work well together, if you went that way), would be better spent on a decent programmable computer.
Suck up the initial cost of a decent programmable computer and reap the rewards both now (installation effort and reliability) and later (tuning to get the best from your engine now and if you modify it).

Look to do the coolant plumbing more inline with the way the V6 75s had their plumbing done. Maybe some more work and expense, but it will be more nicely layed out and easier to work on.
And for a track car (and even a road car), moving the engine back will help the car's handling (<<<stupid generic word). With the plumbing at the back of the engine, there won't be any room to do that.

Put effort into lightening the 2 flywheels while things are appart. The TA engine flywheels have a LOT(!!!) of peripheral mass on them. This deadens the engine's responsiveness.
Same said for the clutch flywheel. Which is permanently attached to the engine, via the tailshaft........ The car has 2, very high polar moment flywheels. No matter what people do with these engines in these cars, with standard weight flywheels, they're still about as responsive as trying to free rev a fully loaded cement mixer.

And consider doing new engine mounts for the car.
The standard Alfa mounts hold the V6 engine on some weird, deliberate misalignment, that is suppose to allow the engine to align itself with the transaxle at some stage............
When, where and why that happens is anyones guess.
Make/have made new, much more rigid and durable mounts that aligns the engine properly with the TA and keeps it there.
Your front tailshaft coupling will love you for it.

[rowan_bris]

It costs a lot.  Mine was completed nearly 4 years ago and cost a small fortune which I have never completed added up and I effectively got the engine for nothing by selling the parts from the rest of the wreck I bought as a donor and did most of the work myself.  I wouldn't go back though.  It is perfectly docile and has the power that the car probably always should have had.

[105gta]

GTVeloce, yeah the pedal box is modified quite a bit for the job. I used a 147 booster and master cyl as the cylinder is mostly inside the booster making it very short and the booster itself is also slim freeing up space for the mintake manifold. I also use a Bmw clutch master cyl mounted inside the car freeing more room.

As for the cost of a 24v conversion it really does depend on how much you do yourself. It can range from very time consuming and relatively cost effective to outrageously costly and time consuming.
In total it has taken a few years of occasional weekend tinkering and design and fab work but it was a hobby for me and I enjoyed each challenge along the way and feel proud as I made everything myself from flywheels, exhaust headers intake manifold, wiring harness etc...
the unavoidable costs are the engine itself and ecu(highly recommend aftermarket) the rest can be made if you have access to equipment (and the skills to use them)or friends that do

As Rowan mentioned, it is worth it if you love driving, it transforms the car and brings it into the modern world. The 3 engine sizes have different characteristics but all perform well. I stuck with a 2.5 24v from a 156 as I like things a little different. Although lacking in low end torque that the 3.2 has it makes up for it in top end power and noise, still with a lot of fine tuning to go and I want to play with cam timing etc..(now that it's run it) my 2.5 currently sits at 180bhp at the wheels but hoping for 200 which is where I want to draw the line for my gearbox.

[105gta]

For those that are considering a conversion and wondering about the thermostat location, it seems there is lots of talk of minimal space around the firewall and complications. This is my engine with the rear mount thermostat showing the available space

[LukeC]

I am getting down to the pointy end of the conversion myself (3.2). Has been a mammoth task but I am within throwing distance...

Compounded by that every active component on the vehicle has been renewed, replaced or overhauled (by myself, not farmed out). We are talking every suspension component  (bushes to PU etc) such as wheel bearings down to the steering rack and pump and fabricating the exhaust myself (conversion of 166 headers). The car also started out as a '86 year sunroof 4 cylinder car that had never had any sort of panel work on it. Paint will be after the car is registered.

305 mm GTA brakes etc.

Just order the Haltec Elite 750 system ($2600 beer tickets): Ouch.

My aim is to make it look a standard as possible under the bonnet. As I have completely renewed the A/C system and installed PS, so there is limited real estate at the rear of the engine... Altering the T-stat housing was no a big issue (when you have a mill and TIG welder).

[LaStregaNera]

For those that are considering a conversion and wondering about the thermostat location, it seems there is lots of talk of minimal space around the firewall and complications. This is my engine with the rear mount thermostat showing the available space

Gets a bit tighter once you put the bonnet latch bracket back in though (on a GTV/GTV6).
I was planning on the thermostat move purely because of the tidier plumbing.

[105gta]

Nice work there Luke C, I'm sure you'll it when it's completed. The engine colour scheme is same as mine. Looks good doesn't it!

LeStregaNera yes the bonnet latch is in the vicinity but well above the thermostat. I can remove the thermostat with the 3 original bolts and nothing else.
Each to their own, for me it was the better coolant flow that decided my positioning I just wanted to point out that the real estate worries aren't as bad as many first perceive

On a side note: for those that have mounted the thermostat at the front have you looked into the coolant flow through the standard head gaskets? I haven't as I left mine at the rear but the positioning and size of holes determines this flow. Something for those mid build to compare between 12v and 24v head gaskets.