As many of you may know i am planning to swap my 4.3L for a 350 small block...

heres where the mind jarring comes in...

What car/truck should i pull this engine out of and will my stock tranny be able to take it. Should i take the tranny out of w/e car i get the engine out of...im new to the game, but im comin up on crunch time and need as much advice as possible.

 

i dont remember if tie 4.3 and 350 share the same bolt pattern or not...

whats your goal, just to put a 350 in it? looking for horespower or just daily driver? carbed or fuel injected? i'm assuming you want an auto, are you looking for overdrive?


if it were me i'd pull the old engine and trans out and put in whatever 350 i found, carb it, and back it up with a 700r4 (overdrive) transmission out of a camaro/firebird. the camaro trannies are simple and readily available since most people are more interested in putting a stick in the camaros. i think i have 2 or 3 kicking around here.

 

I wouldn't do anything with the trans now unless you are planning on wringing out tons of power from the v8. Then, the trans should be rebuilt (not just replaced) to v8 specs. With the newer aftermarket rebuild kits, the trans can be made many times stronger than even a stock v8 4L60E (same trans with more clutch disks in the clutch packs of certain gear sets). Tim (Hanr3) has rebuilt his trans in his Blazer and knows way more about the upgraded internals that I do.

I was going to grab myself a '98-'01 Vortec 350 and just drop it in, add the wiring for the 2 extra injectors, and have the PCM reprogrammed and call it good enough (until the bug bites me again). All accessories will transfer over to this motor as well as all of the sensors. Some wiring may need to be extended. The PCM is the same across the board for the fullsize pickups so only the engine management programming needs to be modified to control the extra 2 cylinders. Other things required would be a pusher electric fan kit for the front of the radiator, motor mounts, and a set of shorty headers. Crank up on the torsion bars a bit to level the truck back out right (if necessary) and you're done. If heat becomes an issue, a larger (more cores) radiator may be necessary.

 

To lunatic: My main goal is to show up the excessive amount of imports in my area. However you recommend i do that is what i plan to do. This is my first ever overhaul and will keep buggin the crap out of everyone here until i am satisfied that i have everything set. I live to do things right the first time.

To swart: i was thinkin of "downgrading" to an old engine with a carb. They're easier to work on and can be tuned a little more from what i have heard. If this isnt advisable please let me know. If it isnt a bad idea how the hell and is it really hard to go from FI to carb?

 

As far as carb retrofitting is concerned, that is a definite route to go, however, do not expect your vehicle to work like stock. For instance, you may end up having to change out the trans for a non-electronic control. Gauges may not work. etc...

Also, depending on where you live and the local emissions laws, you may not pass a safety/emissions inspection by doing this.

By reprogramming the PCM for the engine and modifications you have and using a compatable engine, you can retain all of the factory functionality of the vehicle.

You can make one heck of a vortec 350 that would roast most ricers (at the track ofcourse).

 

Don't have much to add to the post, but I do have a question. How much should you expect to pay for a 98-01 350 Vortec used with low miles? Oh and Swart when are you starting your V8 swap?

 

If I have the money, I'll be starting next summer and hope to be completing it in about 1 weekend. Ambitious, but I plan on having most everything ahead of time.

I can pick up a used Vortec 350 from the local junkyard for around $800-1000 depending on mileage and cheaper if its on sale that weekend.

 

in the end its up to you. i hate computers in cars and dont own a vehicle newer than 1988, so for me a carb is sthe simplest thing to use to accomplish what youre trying to do. the 700r4 is a non computer controlled overdrive transmission and would be my trans of choice for the application.
but whats swart says is correct, you will have emissions to deal with in most instances, as well as what to do for a speedo, gauges, etc etc. i cant deny that a fuel injected computer controlled setup will make more power and run more efficiently.


it shouldnt take too much effort to whup up on ricers though. seriously. whats the challenge in that? ive beaten up on hondas in an old vw beetle.

 

I never said i couldnt beat em, but most of the ricers around here have aftermarket forced induction...usually poorly installed turbos, but still enough boost to outdo my poorly tuned 4.3L

Im gonna keep pricing around...I found an '81 350 out of an old chevy van for $300, but we do have emissions now in all of NY so im gone need to pass that and if the carb is gona make that impossible, im gonna hae to find a cheap 350 vortec...grrrr to the extra money, but i gotta do what i gotta do...

And of course it would be only on the track....where else would people race???

 

If it's money you are concerned with, You should deffinitely go with the late model FI vortec. A beat up 1981 350 will run about as good as your 4.3 does now in stock form. You would have to overhaul and upgrade lots of engine components (cam, lifters,pistons valve-job, springs etc..) to get any real performance gains out of that. Not to mention a new carb, distributor, and fuel pump (you will also have to remove your existing fuel pump and add new fuel lines) All of this and you still need a transmission and you can figure on several other components like water pump, pulleys alternator etc. Yes all of this stuff from your 4.3 will bolt onto an old 350 but the water pump spins the oposite direction so none of it will work unless you use a Vortec 350 and then all of this stuff will work from yours. Just my opinion.