Bought an 85 automatic, 3.07 gears, 111k on the c!ock. Runs strong, smokes a bit on startup (valve seals I'm assuming). Not a daily driver, just something for my wife and I to have fun with. Would like to get more power. No actual number goals, just want to make it sit us back in the seat more. Sooooo.......replace the heads with some smaller combustion chambers, cam, headers, Pro flow intake, bigger injectors, tune, etc, or just give in to the LS juggernaut....? Cost and reliability are top factors. I'd be doing the work, been a mechanic for 30 years, have my own shop with a lift to play in at home. Any and all advice is appreciated.

 

LS transplants are getting old to me imo.

 

I know. That's part of my hesitancy. But it sure seems like a great bang for your buck.....

 

LS! An LS3 with a cam and intake will be a treat. Larger displacement even more so.

 

I say build what you have.

 

If you go LS dont do a heavy iron truck motor

do an alum ls3 style

 

We’ve come full circle. I remember the days of an LS swapped C4 being so rare, only car mags tried it, and the consensus around here was, “just get a C5”. Then they were white hot in popularity once parts to do swaps became normalized. Now the car scene yawns at them, although I think they’re still nice to see. I hear the 5.3 motors with a cam, headers, and the right tune crank out 450+ hp.

The LS swap might be the way to go. If you keep it gen 1 and want big power, it’ll need a great tune. Unless you have a local tuner who works with the old fuel injection tech, a mail order tune will get you kind of close, but not perfect. LSx ECMs are a big step up in tuning and because they’re still so popular, the tunes are pretty on target. Pros and cons to both of routes. Next biggest pro to going LSx besides the reduced weight and power would be the convenience of a more modern ECM.

 

It's a catch 22. The bonuses to the LS is more hp under the curve, ease of working on it once it is in the car, parts availability, and massive power with oem parts.

If you just want more tq/hp well under 6k, then stick with the gen 1. If you want a big power curve to from 3k-7k, a gen 3/4 can easily do that with oem parts and the right cam/spring combo.

I think either way, you are looking at having to upgrade the trans and rear end at some point.

 

My personal opinion, there are so many options now, and a pre-OBD2 car has so much opportunity because the gauge cluster is not reliant on the ECM (for the most part)... meaning that it's powered by the sensors and only takes a few things from the ECM (if at all... like A/C fan control, shift light, etc.). So that means you can easily do an ECM swap from pretty much anything, or go aftermarket. You can basically drop anything SBC/related into this car... it just needs to fit under the hood. LS motor is a nice complete engine package with a lot of support, so why not. But, you can swap in anything else you want too.

 

I’m more of an old school SBC fan than an LS fan, but everyone has their preference.

would replace the iron heads with some AFR195 CNC though

 

LS3 is tough to beat. you will need one hell of a gen 1 motor to compete. and imho even then, it won't - bc fuel mileage, reliability & capability.

swaps aren't easy, but there is a ton of support & info on gen 3/4. you already know that doing anything right is not a casual relationship, no matter what engine you choose.

i will almost always vote engine swap. mainly bc its so difficult to get comparable power out of gen 1 motors.

if youre feeling frisky, try a gen v LT1 swap. i hear they will make some power with the right parts.

 

I'd agree... the only thing that makes me hesitate is the sound. My 84 Corvette, as shitty as it is right now (just got it a week ago and needs to be completely gone through), it sounds amazing. It's the CFI motor, so it shares a lot of the acoustic similarities to what you might hear from a carbureted or square bore fuel injection system. It has a very distinct sound that's different from say a TPI or LS motor. There's just nothing like that sound that a more open-element type of system has... it's fantastic.

 

I don't think LS engines sound as good as a properly built gen 1 small block (key word being "properly").
Beyond that, there are almost no other redeeming qualities for the gen 1 (especially the fuel injected ones) when compared to the gen 3 engines.

Most people overcomplicate their LS swaps and post about how expensive they are. A budget minded individual could do one on the cheap.
I've done a 5.3L/4l60e swap on a 69 Chevelle with a fuel injection conversion, rebuilt trans, and a handful of aftermarket goodies for $2500 all-in that made exactly 3 times the power at the wheels that the old tired 350/350 combo made (same car, same dyno).

If you're going to do the swap and you want it to be worth it over some aftermarket parts on your current engine, you're going to have to take some liberties.
If you're not willing to do that, you'll either need to spend a lot more money or stick with your current setup.

 

I spent several years contemplating this option for my 86 4+3. All of car buddies said to LS is the way to go.
In order to get all of the accessories under the hood the only option is a corvette engine from a C5 without spending $2500-3000 just on adapters and accessories.
Between the cost of the C5 engine and the mods required I gave up and purchased a Summit Racing 383. No mods, used the headers and accessories that were already in the car. Easy
I found it to be a wash in cost. Almost doubled my HP and a huge bump in torque.
I have to be careful with the gas pedal now since I don't have traction control.

 

Being that opinions are like bellybuttons and ******** (everyone has one) I'll give mine.

I have no clue why someone would build a SBC today for more power when LS engines are so prolific. Unless you wanted to keep the car stock then I completely understand doing a rebuild. You can go to the junkyard and grab any LS and put a cam in it and make 350 whp. No other mods just a $300 cam and a set of springs. Spend more and get ported heads and a good intake and you'll be closer to 500 hp. Then there's the possibility of a power adder like boost or nitrous.

In my area a good low milage LS from the wreaking yard will set you back around $350. A new stand alone harness with a fuse block is only $75. A cam with springs is $500. Then there's odds and ends like motor mounts and such. But for under $1200 you can have it done. You'll get better fuel economy and more power than the same money could get you with a SBC.

As to not using an iron LS I disagree. The LS3 is a waste of money. An iron LQ4 or LQ9 is only 100 pounds heavier than an LS3. I've weighed them personally in my freight scale. But the cost of the motor isn't worth the weight reduction. My LQ9 makes more than enough power. If I want to go faster I'll just add more nitrous.

Something else to consider in a LS swap is selling un-needed parts. So after the swap you can sell the old engine, ECU and whatever else you don't need. This seriously offsets the cost of the swap.

 

If budget and reliability are high priorities, probably better to go LS. The cost of all those mods adds up quick, and LS's are not that expensive. The wiring will probably be the hardest part, and even that won't be so bad once the old engine is out. I haven't done an LS swap though, so don't take my word for it.