Which EFI System to fit to a 3.5

[Skiboy]

I have 2 efi engines - 3.5 and a 3.9 with all the bits
I also have a better 3.5 holly carb motor - this is the best of the motors and I want to use this in a project.

My question is can I take the 3.9 injection system and throw it on the 3.5 carby (manifold and all its connections) and that is all I need?

Or am I better to use the 3.5 (more weathers and maybe dodgy) efi system?

Advice and questions from those out there in the know please.

[discowhite]

ive just bought a p6b 3.5 hi comp block fitted with 3.9 parts and efi, all the electricals are now haltec E6X.
3.9 efi to 3.5 carby should be a straight swap.

cheers phil

[PhilipA]

To be a purist you should just grind cutouts in the inlet ports where the cutout is in the gasket.
You can stuff each port with rags and seal the V and do it in situ. Use avacuum cleaner to get rid of the swarf.
Regards Philip A

[BigJon]

Logic dictates that the newest system should be the best. Having said that, my 3.9 14CUX uses HEAPS more fuel than my 3.5 flapper ever did.

Also, if you are fitting EFI onto a carburettor engine you will need to modify the intake ports on the heads. They have a little section ground out for the injectors to fire past.

Philip beat me to it!

[jazzaD1]

have you thought about megasquirt? i've changed the 14cux for a megasquirt system, it can be a headache at times, but the tuneability is amazing, i guess it depends on what mods you have planned for the future

[PhilipA]

My question is can I take the 3.9 injection system and throw it on the 3.5 carby (manifold and all its connections) and that is all I need?
Yes.
Except you need an efi fuel tank , pump and return.

You can make up an efi fuel system wiith an aftermarket Bosch injection pump. ( I used an SD1) , and a surge tank. I used the facet as a feeder pump, into a surge tank I had made from a approx 150MM length of 75MM exhaust , then into the bosch pump. I used the original fuel return hose .
The pump and high pressure pipes are an expensive part of the conversion so best if you can find an old efi tank and fuel lines.
Regards Philip A