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305 to 400

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305 to 400

Jamie Erwin Jamie Erwin
New User | Posts: 1 | Joined: 11/13
Posted: 11/05/13
05:39 PM

305 tbi swap to 400 tbi. Will everything interchange?  

wayne712222 wayne712222
User | Posts: 198 | Joined: 10/13
Posted: 11/06/13
07:25 PM

yes. depending on the heads.. ..  

most TBI manifolds use the modified angles on the third and forth bolts of the six on the intake.. so.   on a carbed engine.. the six intake bolts stick out like this..

1-  2-  3-  4-  5- 6-     all at the same angle..

the TBI heads used raised center bolts..

1-  2-  3/  4/  5- 6-

you will have to change the injectors..   as 305 injectors DO NOT supply enough fuel for the system to properly work in open loop.. where it does not run on feedback from the oxygen sensor.

you will probably need a pair of the smaller of the 454 flow rate injectors.. i don't know if the 9C1 injectors would be close enough to make it run properly..

there is a bunch of stuff that needs to be talked about..

and you might actually depending on which heads...  run a conventional 4 barrel intake manifold with a TBI adaptor..