3.4l swap to lt1 how hard is it? And will my 5 speed hold up

**Tealcamaro** · 08-28-2012, 02:31 PM

So I have 95 3.4l and am going to swap to the lt1 that had an auto so will the computer from trans am work?

**cRacKy34610** · 08-28-2012, 07:18 PM

I haven't done it, but from what I've read unless you plan on putting some serious money into it going to a v-8 isn't a fun project. I have heard that going with a carb motor cuts down on the cost but you might want to look at some older posts about the 3.4L. There is one in particular, http://www.ls1.com/forums/f68/some-i...hv-motor-4706/ , that I am looking into just because it would be half the money if not less. The link provided above is one of the posts that I've read. I have a 94 with the 3.4L (second engine) with 91k on it and I'm researching the mods done in the link vs. doing an engine swap. But for what your asking, many others may agree, buy one that has the 8 and if it needs parts to make it nice, use yours or sell yours to buy it. You have more to worry about than just the computer and tranny, rear is gonna have to be changed along with suspension, radiator (I believe) , motor mounts have to be fabricated unless you find a kit. But if you go with it good luck and let me know what all had to be done.

**Smittro** · 08-29-2012, 02:47 AM

Refitting your 3.4 to an Lt1 will take a ton more than the "computer".

Everything will need changed, from the dash cluster and k-member, to the rear end, and drive shaft.

An Lt1 would be a down grade imho.

The after market and tech exsists now to biuld an N/A 3400 that will walk a lt1.

Not to mention it's about 100++ pounds lighter.

**Tealcamaro** · 08-29-2012, 09:56 AM

Well I have a whole parts car with everything I need. I was just wondering if the computer out of the parts work from it being an auto and me putting it behind my t5.and my car has a 2000 SS limted rear with 2000 SS driveline.
And I wanted to do the 99 grand am gt top end swap but it would be cheaper and more hp to just drop the lt1 in it.

I would really like to keep my 3.4l and build it but I have not seen a 500rwhp 3.4l.
But if u know of away to get 300hp out of my 3.4l for under a grand let me know thanks

**Smittro** · 08-30-2012, 05:05 AM

T5 setup for v6 won't hold 300hp or for long especially if you plan on any racing, (street or otherwise), and the bell housing won't match the LT1.

There was a reason all the T5's were only bolted to 305 v8, 3.1, and 2.8 in the previous gen f-body, and only the 3800 and 3.4l v6 4th gens.

The LT1 got the 6-spd in 93' and up, as well as the Ls1 cars getting the t-56.

It's going to be hard to build the Lt1 for 300hp and do the swap over with a $1k budget.

Not trying to discourage you though. You should be able to have the ECM changed if needed from auto to manual transmission.

But the v6 ECM will not work. You won't get 300 out of your 3.4 with grand am 3.4 high feature heads either (which you likely know already).

The 3.4 in your f-body is also slightly less displacement than the 3400 high feature for FWD applications.

IIRC 204cid for the RWD all iron motors, and 207cid for the high feature aluminum head.

**Tealcamaro** · 08-30-2012, 10:10 AM

Okay I am going to buy the top end of 99 grand am. Do I have to change my pistons? But other than pistons everything else on the grand am I just use there stock setup right?

I was also wondering about emisson stuff will I have to just rewire my current setup to the 3400 intake and heads?

**Smittro** · 08-30-2012, 04:27 PM

Should'nt have to if your cam is stock in the .40 lift range.

I'd only look at valve/piston issues if you use an after market cam that's going to be over .50.

You may have to lengthen some of the harness and/or change/mod it some.

You may even be able to just exchange some of your 3.4 RWD top end sensors over to the new top end..

**Tealcamaro** · 08-30-2012, 07:25 PM

Well im wanting to go with 262 crane cam. And also havin trouble finding headers for the 99 grand am. And is there a difference in heads from the 99 grand am and the 99 grand am gt?

**Smittro** · 08-31-2012, 06:13 AM

Not that I know of.. I don't think there's a big difference if any on the ram air cars either.

To make a correction GM is also listing the RWD engine as 207CID. I must have been thinking about the LHO RWD engines.

Headers,, good question,, I'll see what I can dig up on them.