Fuel Injection on a 305

[OJK001]

I have a 84 gmc sierra 305, I am looking into turning my carb set up into a fuel injection. Anybody with info or kit to use? just doing some research on what I need.thanks

[Pyrotechnic]

A TBI setup from a 305 will work, as will a TPI setup from a car. Good factory setups that can be had for cheap and will run as is with no tuning. The TBI is fairly simple and performs well. The TPI is more complicated but will most likely make more torque. Do some searching on "TBI swap" and "TPI swap"

[D13]

Buy used GM parts for an '87 TBI, or up to '91 Burb/Blazer/1 ton. The 305 throttle body is different than the 350. You will need an adaptor plate at the intake, or a FI intake (availble dirt cheap) with the matching heads (center 4 intake bolts are re-angled). Or go aftermarket. use an inline fuel pump.

Tuned port, easiest to swap complete motor, need a lot higher fuel pressure and more wiring.

[gchemist]

So you want fuel injection?
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[rfmaster]

Originally Posted by D13

Buy used GM parts for an '87 TBI, or up to '91 Burb/Blazer/1 ton. The 305 throttle body is different than the 350. You will need an adaptor plate at the intake, or a FI intake (availble dirt cheap) with the matching heads (center 4 intake bolts are re-angled). Or go aftermarket. use an inline fuel pump.

Tuned port, easiest to swap complete motor, need a lot higher fuel pressure and more wiring.

Throttle bodies TBs used for 305/350 are identical! Small block TB have 48mm bores, while 454 use 52mm bores. The difference between 305/350 is in injector lb/hr rating - 305 use 55 lb/hr while 350 use 62 lb/hr. 88-92 BBC injectors are rated around 90 lb at 13 psi. You can bolt up TB to your existing Q-jet manifold by buying adapter plate - available from many sources (Mr-Gasket, others), or alternatively using later manifold as outlined above. If you do not care for adapter plates or modifying later manifold Holley makes a TBI specific manifold for early heads - HLY 300-49.

TBI system requires 12 to 15 PSI to be happy while TPI needs 45PSI. High pressure fuel system require planning and careful fabrication. Successful, low cost FI swap needs a complete donor vehicle, otherwise piecing it all together takes time, effort and naturally money. But rewards are many!

//RF

[OJK001]

guys thanks for the info...will help me out alot thanks.

[gchemist]

TPI is the best FI for a 305. Other FI system work better on larger bore engines.