Hey guys,
Looking at buying a cheap '97 ECSB with the 5.0L and then swapping in the L31 shortblock and some vortec heads. Are the intake manifolds and throttle bodies the same? I would also need to get an ECU for an L31 right? I'm thinking everything else can be transferred from the 305 to the 350. So the list of things I need would be:
L31 shortblock
vortec heads...the 305 uses smaller valves and combustion chamber
intake manifold and throttlebody unless it's the same as the 305
bigger (19#) fuel injectors?
stock L31 ECU
Let me know if I missed anything.
TIA!

 

I remember lookin around for l31 stuff back when i was doing the efi conversion on the dune buggy. I don't think the manifold/tb is the same, I could be wrong though. I'd just buy an aftermarket intake or maybe could you use an LT1 intake? what're your plans for the motor?

 

No plans for the motor really. I just want a reliable setup with the power of the 350. I figure I can get the truck cheap and then spend maybe $2K tops on the L31 swap and I'll basically have a new motor. Only mods I would do down the road are maybe CAI and a catback.

 

vortec heads require an intake made specifically for them.

 

Right but I heard the 305 has vortec heads on the later years...is that right?

 

It does, its a similar head with smaller valves, runners and chambers.

 

So is the intake manifold the same for both and how about the throttle body?

 

They're the same.

 

the 305 and 350 are very simaliar actually. the TB, and intake are the same i believe.

 

you could go to autozones website and plug in the year of the vehicle your looking at the look up the part number for the gasket for a 350 and 305 and see if they are the same.