98 350 to 97 305

badshow · February 13, 2017

hey guys

i have a 98 1500 4x4 p/u and the head gasket blew in the 350 engine that was in it, so me thinking this would be a faster deal than re surfacing the head i put my 305 engine from my 97 4x4 p/u.

once it was installed i fired it up and it ran like shit.. then when u give full throttle it bogged out. hence flooded with gas.

i since have changed spider injection entire assembly with fuel pressure regulator. changed mass air flow sensor. blew out gas lines. blew out fuel filter. unplugged tps to see if it starts... and nothing ... it has gas washed itself and i drained oil, cleaned plugs and fired up, ran and did the same thing... not to sure but it seems to me like it floods when it shuts off.... question is wth is going on?!?!? and also i have the 350 fuel pump still in the tank could this be the cause? not a 305 fuel pump? and i have swapped out the computers from 305 to 350 made no difference.... only thing i did recognize is that the wiring on the truck is for the 350 computer which only has 4 connections. the 305 computer from old truck has the same 4 connections but also has one more connection in the middle.. what is it and could that cause a problem?

anything would help thanks guy

barry G · February 14, 2017

the fuel pumps are the same today as 1996.

55psi is the goal. Really simple 2 decades now.

In fact, that is the number 1 fix for the first vortecs. The original 55psi was bad in more than one way, including the gauge sender unit near the pump..

My own even sounds like an LS with the new pumps. I simply went with carter, the later-than-2008 version.

not sure what is up with wiring for you.

there is a static pressure for every engine, computers know it exists. the 350 is a borderline volcano compared to the 500k with no rebuild 305...

food for thought. computer may be burned into another ground signature.

sensitive stuff. Resort that for last, find obvious things before then.