Hello again,
first I must come clean and tell you that I build American engines for a living so my comments might not seem entirely unbiased. Also all this IVA emissions stuff is a UK/Europe only problem, but problem it is and it's going to get worse if Brussels has its way.
I have been using EFI on some of our engines for three or four years now so have found the previous comments interesting and the price ranges VERY interesting.
If you are going the EFI route in the UK for a new build then you must have emissions checks foremost in the picture, OK, more power, better response, better starting hot and cold and A LOT better economy but all no use if it won't pass an emissions test.
Unless you can do a lot of the specing, building, wiring etc yourself then go for one of the "plug and play" everything in one box kits. Some can be fairly limited in their capabilities. The Mass-Flow system was mentioned, it works fine if you get the engine combo right , but the trouble is it's "self learning" and if the parts combination isn't right then you will never get it to run correctly. They use a stock '88 Mustang ECM so if you need the map altering it has to go back to be "re burned" , OK if you live in the US, not so good in the UK.It was mentioned that the cost bore comparison to a carb and manifold but at $3000 for the kit, you must have some very expensive carbs in the US !
The Edelbrock Pro Flo 2 that was mentioned, again works well but we know of one manufacturer here in the UK that had major problems with the IVA emissions and gave up with the system. The Edelbrock is not self learning but the calibration capabilities are limited when it comes to fine tune, also it HAS to use 302 firing order, no 351 firing order roller cams etc. Both those kits are the four barrel throttle body types with multi port injection, come complete with distributor pumps etc. They take a standard air cleaner so look "vintage"
Holley are bringing out some new kits later this year, we have the demo software and it looks like it's aimed at late model US stuff. The old style Commander kits are now obsolete but some warehouses are still selling them, so look out.
We use the Accel DFI kits which, again, are complete and come with like the others, the manifold, distributor and ignition box etc, fully sequential, wide band and all the good stuff. It's far and away the most adaptable in terms of tune and we can guarantee to get even the most fruity of V8s through a CAT or regular emissions test. Prices have been mentioned on this thread for other kits so I wll say that the Accel kit for a 302 goes for arround the £2650 mark for the four barrel, depending on spec.
If you want the 8 stack look then we do the TWM,(
www.twminduction.com) and for the real "Webber look" have a look at
www.dynaformance.com The TWM we find is better for higher power engines as it comes with up to 50mm throttle bodies and are shorter, the Dynaformance has definately got the "look" but only comes in 48mm.
The Dynaformance electronics, as it comes, are awfull so we have had ours converted to Accel fully sequential. Accel did all the work and mapping on the Roush IR motors that use TWM so we know it works well and have adapted it for the UK regs. So there are no crazy theories on pricing, can I say that they both sell, complete, for arround £5000 depending on spec, the TWM a bit less.
If you want to go the four barrel carburretor route,Brett mentioned the Holley "Street Avenger", we have found these to be the cleanest four barrel arround so can recomend those from an IVA point of view.
Webbers, for IVA, it must be IDF but for pre '75 you will get away with IDA but for how much longer. To dispel the myth they go for about £2250 complete, both types. (by the way,all the above don't include any tax)
Hope this has been of help, Mike