so i have a 98 3.1L and i really want to put a L67 in but time and money and not having a car for that long just isnt going to work for me right know, so i have heard a little bit about a top swap. few questions about it
what is all intailed?
is it worth it?
does anything have to be done to my PCM?
will i be able to even tell a difference?
or is it pretty much a waste of time?
i read alittle bit about it awhile ago but just started looking back in to it, any help would be great thank you all for your time

 

Typically, when one talks about a "top swap" they mean that they want to put an L67 top end onto an L36 bottom end. However, in your case you have an L82 and want to install the top end of an LA1 (3400 v6).

What that means is that you're going to replace the heads on up of your L82 with the heads on up of an LA1.

If you can get the parts really cheap, then the top swap is worth it. It all depends on what the price is.

The PCM does not need to be tuned, but a tuned PCM will only give you more gains.

In my opinion, I would rather just swap out the L82 for an LA1. IIRC, even with the LA1 engine swap you won't have to swap PCMs or anything. Simply remove old engine and install new one.

 

Top swap from N/A to N/A? Sounds easy enough for all of the gains you get. 5% more hp then a 3400 swap.

 

ok than is that all i need is heads and intake? or do i need other stuff also, such a fuel rail, injectors, sensors, ext? thanks again

 

X2, I'd rephrase the title to say something like 3400 top end swap/conversion or something like that- 'top swap' has become the common name for putting an L67 top end on an L36, and you'll just get a lot of people thinking that's what the thread is about- especially people searching it later.

 

The N-body guys have done a lot with the 3100 and 3400 v6 lines. If you Google search, there is a guy who published a PDF of ALL the details to swap a 3400 into his '95 Grand Am (originally with a 3100).

Yes you will see gains from a top swap with 3400 donor parts. This starts with the simple fact the throttle body allows more air into the system and to make it worth while, you need the rest of the equation. But I side with Zipper, if you are going to mess with it, go for all the marbles on this one. Pulling a 3100 and popping in a 3400 is 99% a direct swap, no PCM change required. Keep the 3100 transmission. Then you have the full gains of a 3400 100%. You'll be faster and happier and I doubt a full 3400 v6 is too expensive these days.

Google search for that write up and read it. It's a lot of helpful info (your swap will differ due to differences in the years, but the guy did a fantastic job documenting the process to give any beginner an idea of what he went through and some things to expect, it will even help educate you to do a top swap).