305 TBI to 350 TBI - Your thoughts?
 

Ladies and gents,
So I got a good deal on a 350 from a friend of mine to replace my oil burning 305. I have a few questions and I couldn't find a good answer from searching so I hope some of you can help out.

The 350 is currently set up with a carb and has a mild cam yet I don't know the grind. Hasn't ran in years but we got it to fire and it ran pretty good when it did, didn't sound lopy.. It has stock type cylinder heads and I plan to swap my Trickflow cylinder heads over to this 350 and purchase holley's 350 TBI manifold and their throttle body to go with it along with new exhaust manifolds so I can keep fuel injection. I'm also going to be using it's trans since mine currently started leaking.. It has a 700R4 that I'm told is an aftermarket performance trans but since the engine is carb'd I'm assuming a lot will need to be swapped over from my trans so things like the speedometer work and it shifts and what not.

1) Do I need to swap my computer? (I heard people like the 350 computer off police pkg caprices.) If I do swap will I need to change wire harnesses or ends of the current ones going to stuff like the throttle body?

2) Will it be possible to keep my lock up torque converter and all the oem gages operational?

I'm not going to be doing the swap since I don't have the tools for the job so I gotta have the stuff needed when I drop off the car.

Thanks in advance,

Derek

No, but if you don't, you'll have to reprogram yours. Very likely anything you get with a factory tune wouldn't work quite right, anyway. So, plan on a custom tune.

There is nothing about a 350 that would affect those things.

Re: 305 TBI to 350 TBI - Your thoughts?
 

Thanks for the response five7.
I wasn't sure about the gages and also the electric fans since I don't think Caprices had either.. But I don't even know if the signal for the tach passes through the ecm or not as well as oil pressure and the electric fans...

In any event it's possible to have them just reprogram mine to support the 350? That's good news, I know there's that one guy a lot of people seem to like, I have his link on my desktop for that reason.

Thanks again for the advice,

Derek

Re: 305 TBI to 350 TBI - Your thoughts?
 

This is a popular and well documented swap
https://www.thirdgen.org/forums/tbi/...-350-swap.html
https://www.thirdgen.org/forums/tbi/...ck-sensor.html

1) - no, a chip with a coustom tune or the EBL flash upgrade will do the trick.
2) - the VSS is in the tail shaft and you will probably need to use yours anyway. Make sure the transmission has the factory working lock up wiring harnes, some "performance" builds have OD lock up only.