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3.1 MPFI to 3400 V6


CutlassSL91

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Do you think it would be worth it to switch a 3.1 MPFI to a 3400 185hp V6? Is this a pretty simple swap or a lot involved? would a 1991 4-T60 NON ELECTRONIC trans work with it? The 3.1 is a great smooth quiet running engine but it's too slow. A turbo would probably be more work that i'd like.

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i'd say it would be pretty easy but you'd have to run it with the 3.1 MPFI's electronics and a custom chip...not sure what the wiring difference would be though.

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It takes a bit of work on the older W-cars but if you can get the parts cheap from a junkyard and have the car hung up a few days, I say go for it.

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I should probably ask a bunch of questions about the 3400:

 

Does it have about the same sound as the 3.1 MPFI (good "dual" exhaust sound magnaflows?)

 

It it as smooth?

 

Reliable?

 

Will I notice a good amount of increase in performance?

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Most pushrod V6s have generally the same sound.. can be nice and deep in the lower rpms with the right (or lack of) exhaust, but it loses the deep tone once you get past 3300ish rpms.

 

And it's generally accepted that any GM 60* V6 is pretty damn smooth and reliable. and you'll DEFINETLY notice a boost in performance from a '91 3.1...

 

I'd go for it.

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very simple, the 4t60 will bolt to the 3400, u will need a chip from a 90 w-body (3.1 mpfi / 4t60 without a MAF sensor), and 2 rewire the SFI to run as MPFI, there is a very good writeup about how to do it if you use a search. I would suggest using a stronger transmission the the stock 4t60 from the 3.1, either a TGP 4t60HD or a 4t60E froma 3.4 car or converting to a manual transmission.

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Depending on what type of car your getting the engine from, a stock 3400 is rated anywhere from 170-180HP. I'm just being picky. :D

 

 

Aaron

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http://3100mpfi.com <- guy who put a 3100 in his car and used the 3.1 computer

 

Anyways I notice the 3400 is a pretty peppy engine. In the IMPALA, a big car, it feels faster than the 3100 in my GP.

 

As far as exhaust, nothing quite has the same sound as the 2.8/3.1. That's why I always loved flooring my 1988 GP so much, I really don't drive my current car that hard at all...

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you wount get more then a couple hundred for a 3.1/4t60, hard to sell. its a bolt in job but if patgizz says u need a custom chip, that will run ya some $$.

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Check out http://www.3400swap.com too.

 

The 3400 (LA1) is a pretty soild engine....it does have the intake leak problem like the 3100 and MPFIs do. Hell, intake leaks are pretty much known GM wide.

 

You can pick the engines up pretty cheap.....I paid $345 for a 3k mile off eBay.

 

I went from a 15.8 @ 87 to a 15.2 @ 90 mph....everything else being the same.

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