Originally Posted by strutaeng

I don't know anything about the F body's, but I would think it would be a plug and play mostly swap, given how GM built vehicles on these generations with the different engine combinations. The LM7 would be very similar to the LS1.

I did a 1999 Silverado RCSB 2wd 4.3 to 5.3/4L80e swap about 3 years ago and everything was plug-and-play. Just got VATS deleted from the 5.3 ECU and reflashed for the transmission and the harness repin. The engine is bone stock and made the truck so much more enjoyable to drive. ☺️

You are going to love it!

Originally Posted by skl3t0r

I want to swap a 5.3l lm7 into my 1997 bird with a 3.8l v6. I'm looking for information on the swap- problems in compatibility/install/running, etc. From what I've read, The lm7 should just bolt straight on to ls1 mounts with no issues, and I'm assuming all other accessory components should fit as well? I know heads/intake go right on with no problems. Also, regarding the wiring harness, Is it worth it to grab a terminator X to avoid having to buy a new ECU, or is it a smarter choice to bite the bullet? What else should i know about the engine or the car before i make any final decisions and go through with it? If anyone has info on the swap it would be greatly appreciated!

Also, I don't want to sell it and buy a new one. It's Bright Purple Metallic.

Originally Posted by skl3t0r

Oh my lord. you don't know how much of a relief that is to hear. almost everywhere i've asked so far i get "buy another car" or something else that feels negative. I have the whole build priced out already. Got a spreadsheet going and everything. Just have to actually buy the parts LOL

Anyway, I really appreciate that! thank you for telling me.

Originally Posted by bleepster

Can I swap one of these engines into my V6 F-body?

While it can be done, installing a larger V8 engine into a car originally equipped with a lower output V6 is generally cost prohibitive and not recommended. Swapping to a LS based engine will typically require a new transmission, engine cradle, radiator, fuel pump assembly, gauge cluster, PCM and wiring harness, strengthened suspension components, and new throttle assembly. With the low cost of entry for these cars, it may be more financially solvent to sell your V6-powered F-Body and buy a V8-powered one to replace it.

Any additional components I may need for a swap?

When swapping in a new engine, be sure to have the correct oil pan and exhaust headers/manifolds needed to fit the F-body chassis. Using an intake and fuel injector setup other than the LS1 components will require a new wiring harness. Additionally, you will need the correct LS1 accessories/accessory brackets to properly fit everything in the engine bay.

taken from: Camaro and Firebird: Guide for Budget Engine Swap | Ls1tech

also a good read:
V6 to V8 swap thread | Firebird Nation

Originally Posted by Spamfritter

I'm not entirely sure how many things are different between the V6 and the V8 fourth generation F-bodies. The best thing you could do would be to get a running donor car and swap over everything you need, taking the time and spending the money to replace anything that is likely to fail anytime soon due to mileage, age or whatever. As far as the ECU and wiring hardness goes, I'd use a 2001 to 2002 V8 wiring harness and ECU for an LM7. Things you may have to contend with are motor mounts, front suspension springs, radiator, hoses, alternator, accessory drive, and I'm sure I've forgotten a couple of other things.



There are two sides to this coin. People telling you to sell your car and buy a different one are trying to save you some time, money and effort. The costs may or may not line up where it makes more sense to simply sell your car and buy another. If you want something like a specific color or other options then availability may simply not be there. The car being purple is pretty odd and finding an equivalent V8 car can be next to impossible. One often overlooked fact is that many of the V8 cars have lived hard lives. Unless they are relatively low mileage examples, most are ragged out and beaten pretty hard. This takes a toll in a lot of ways people don't seem to notice in the form of beat up and scratched up interior plastics, missing parts, paint damage, trashed under carriages, grenaded rear ends, and the list goes on.

A lot of the V6 cars aren't necessarily as ragged out as their V8 counterparts. Sometimes you will see absolutely gorgeous low mileage V6 cars that don't fetch a high price. Sure, its more work to swap a V8 in and there is definite cost increase that comes into play but at the age of these cars, a lot of things factor in. A lot of times you can buy a ultra-cheap V8 car that doesn't run but gives you what you need in terms of wiring harnesses, motor mount pedestals or other things. It can be potentially easier to handle as you could pay a lot less for a V6 car and build it over time versus dropping 20K+ for one of the better V8 cars.



While this can be true, it's not universally true. I've seen complete non-running V8 cars for pretty cheap. Some of the junk yard LSx's you can get can come with some of what you need or a lot of it for a really low price. Again, it also allows you to sometimes build something that's more unique. If I had a V6 car with perfect paint that was one of the rarer colors with a near perfect interior, I'd be looking more towards the swap versus selling my V6 car and then spending $20,000+ on an equally good example of V8 car. At one time this advice was pretty solid and nearly always true but after so many years, I think you have to take these things on a case by case basis. What does the OP have exactly? Why is he swapping it? What would he get for the V6 car versus what it would cost to do the swap, etc.?

Originally Posted by blackbyrd

Chassis is the same but K member has different mounting points. So you will need a v8 K memeber or an aftermarket one. Ive done the swap mine was an 01 v6 auto, now v8 manual.
I can assure you its not quite plug and play. as long as you stay within in years like swapping an 01 our to an 01 fbody v6 for v8. While its mostly stated that that 99+ engine harnesses differ from 98's and the ecms are different as well. You can make it all work, again though you arent going to unplug the harness and swap them over directly. Theres also some mechanical differences, like fuel lines, brakes, and power steering differences. suspension will also have to be addressed front springs differ slightly from v8 to v6 as well as sway bars front and rear.

When I did it I used a stand alone harness and guages and kind of ditched to stock stuff, though I dont think thats what you are going for.

I did this nearly 20 years ago now so I cant remember it all but what I found was on this site, there were several that did the same swap. So its all here just gotta search for it, you will likely see some of my posts and questions as you dig haha.

one thing I dont know is how much different the v6 systems were between the 95-97 3.8 and the 98+ 3.8? I know the electronics changed quite a bit from lt1 to ls1 so that may hurt you a bit, not sure.