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304 efi to 4 barrel carb or efi


New Member
Jan 27, 2009
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Stokes Valley, Wellington, New Zealand
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vn commodore
Hi guys.
Just picked myself up a vn executive thats been converted to a v8 using a crashed calais.
Am looking at loosing the factory injection manifold, have already got a redline hi winder manifold in the garage so am looking at either going carb or a 4barrel throttle body system.

Now if I am to go down the carb route I already have a quickfuel vac sec carby, what is the deal with the fuel pump, just a matter of fitting low pressure pump or what? Also whats the deal with the dizzy does an early 308 work or is there away to run the factory one or do I have to run a standalone ignition system?

Now if im to stick with efi how do I go about these efi throttle bodies, like what sort of size would I be looking for, would I get one with the injectors on the tb or be getting the manifold drilled for them . Also would the factory ecu be able to run this or would I need to get an aftermarket computer?

I will be doing all work myself and am in New Zealand so will not have any legal issues with going carb and dont want to go with any other styles of injection, will be 4 barrel regardless.

Cheers in advance.
Last edited:


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Feb 20, 2011
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Get a fuel pressure reg to suit carby, they are around, 4-7 psi from memory is all that is needed for a carb.

Early 253/308 dizzy will fit, but another option is to leave the ecu controlling the spark and getting all the afr and o2 error codes disable in the tune (jump 12 volts to the injector voltage monitor pin) and should do it.

Fuel doesn't mix with air very well, so if staying efi then have the injectors placed as close to the intake ports in the head as possible for the best performance, this is why it's not recommended to smooth the intake when porting to much as the rough edges help to keep the fuel suspended in the air better.

Factory ecu is more than capable, have a look at pcmhacking (formerly known as delcohacking) to see what the old vn/vp 808 can do.