Hello Im new to the forum, so sorry if this is in the wrong section. First off I have a 1995 chevy blazer 4wd and Im looking to swap the stock 4.3 for a SBC carbed 350. I have read somewhat on this swap and I plain to read more so I was looking for some more info about it. Sence I am going with carbed do I have to change or reprogram the computer? Im guessing that my stock auto tranny wouldnt bolt up to a 350. So more info is greatly appriciated, thanks.

 

[sm=welcomesign.gif]to the Forum. If you haven't seen it yet, check this website.

 

The 4.3L is just a 5.7L (350) with two less cylinders. Bolt pattern is identical. The problem that you will run into is that the transmission is electronically controlled. It will not like losing input from the engine for configuring shifts. You can purchase a stand alone controller, but they are $$$.

And definitely check out JTR.com

 

hey swartlkk, in your opinion, what would be easier to swap in, a vortec 350 or the ls-lq9 6.0l? and, what will be easier to mod? both used and if need be, the trans come with for a little more.

 

Depends on the year of vehicle (what you are driving) and your definition of easy. For the 96 to mid-02, the SCFI Vortec 5.7L engines are by far the easiest of swaps as the PCMs are the same and only minor wiring changes are necessary. You can make it look stock and even pass a fairly stringent emissions test too.

The LQ9 was never offered in front of a 4L60E, only the 4L80E and then the Allison so transmission control may be difficult off of an LQ9 PCM.

 

Thanks for the help guys! So what you are saying swart is that the auto wont work but the 5 speed could? I could spend some more time into swapping out the computer and so forth to make it a 5 speed. Or what about the old turbo 400/700's transmissions, would those work?

 

Since they do not require electronics, they would definitely work. You would then have to possibly modify the driveshafts to get things to fit, but that work at least you can see what needs to be done. Electronics on the other hand...

 

so, if i were to bolt up my 4l60e to the lq9, i would have problems? and you say a 350 would be easier since i (my 98) has the same computer as the 350 and the 350 has been bolted to 4l60e. i thought the lq9's where, i mean, its a cast iron ls2 and ls2's are bolted up to a 4l60e.

 

Well, yes, the LS2s are practically the same. Just if you were sourcing all of your parts from one particular vehicle, the LQ9 being a truck motor, it gets put in front of the 4L80E or the Allison. You will probably need to have the PCM retuned anyway so you could have the tuner drop in the code for the transmission. Or you could source the PCM from a vehicle equiped with the proper combination (LS2/4L60E).

Before you do much of anything, you will want to take a look at the PCM pinouts to see how much needs to get swapped around.

 

ok, thanks, i read up on it and have more question later. lol