They don't seem to have much hp stock.

 

they are the 2nd worst engine manufactured by gm or whoever for the camaros and firebirds in 3rd gens. Mine sucks Im thinking of getting a 350 L98 or jsut sticking with my pos and have a uniqly fast 305.

 

I put 267,000 miles on my LG4 in my 85'. I had good power...no cat, some free mods, shift kit. From 100K to the 267K I changed the oil about 3 times. It still runs and performs admirably...probably mid 15's at about 85+ mph. It would spin my tires and spin going into 2nd gear on 235/60/15 tires.
I quit driving it because it was beginning to use oil (about a quart for every 250-500 miles), and I was beginning to get worried about its dependability.

Let me say I did not baby this car. I drive it hard everyday. The car was very very good to me. So I think the LG4 is a good motor.

But if you want performance...it will take some major modifications, and you are better off getting something else.
My Lg4 had good power, though I always wanted more, and was very dependable, and economical.

 

I feel the LG4 was one of gm's best built engines. they don't have many problems aside from lack of hp. i once pulled one out of a plow truck that still ran, but had so much sludge in it that the a couple of the rocker arms wouldn't stay on the valve head. the sludge was pushing them off. they seem to take a beating and just keep going for more.

 

They're good for a rebuild. The stock cam, heads and exhaust are pathetic.

 

I agree with zippy, the 305 is a very reliable motor. It's reputation as a "piece of crap" is not deserved. The poor reputation results more from it's performance or should I say, it's limited ability - primarily due to it's narrow bore thus limiting your choice of heads (no 2.02 Intakes).

In spite of the 305s handicap in head selection (due to the narrow bore), good power can be obtained from a 305 if you chose your build carefully. The problem is, the cost of building a 305 (intake, heads and cam) is the same for a 350 and you are more limited than a 350 (again, primarily head selection).

As long as you realize the limitations of the 305 and have realistic power goals, the 305 can be made be made into a nice performing engine and be quite reliable. Just remember that the same mods on a 350 will result in 15% more (due to the larger displacement).

 

I have to agree the LG4 carbed is a well made engine in terms of quality.
They are also easier to make horsepower with than the TBI model.
Car craft(?) made 325 hp with one with head,cam,and intake changes.I have seen other LG4 articles where they made 400hp.

 

Heh, I also have an 85 Z28 auto though.
In stock form there fairly descent for power considering fuel economy 18+ city.
They just lack descent flowing heads and a cam.
If you were to change heads and cam maybe do some exhuast work you could really make that car fly.
SSC

 

Ok, maybe I'm reading this wrong but... are you saying you changed your oil 3 times in 167,000 miles? What the... were you using that redline or something!?!?!?!

 

mostly to sum it up as a reliable engine yes, its not bad, but as a power engine is the worst (probley second to the CFI)

 

Yeah, but does it ever respond to a few simple mods!

Headers and exhaust=30 hp
Intake=20 hp
Ignition tune up and carb tweak=10 hp

All of a sudden that little 305 is pushing an honest 200 hp net

A dual snorkle aircleaner=20 hp

Then build a set of heads and add a camshaft that will also work well on a 350 and you are heading for an easy 300 gross hp.

That will have running into the 14s, no problemos

 

I consider CFI an "Induction system" and the block family as the "engine". No disagreement that CFI has a lot of problems as an intake system. Though there are guys who have made CFI perform, especially now that people are adapting the 7747 TBI ECM to the CFI to allow tuning flexibility (the biggest issue with CFI).

IMO worst SBC (from a power perspective) would be the 267 V8 of the late 70s/early 80s, again, due to its extremely small bore. Again, this is strictly from a power perspective. I have seen some 267s hit some high mileage also, so they do seem to have the typical longevity that we expect from our SBCs.

 

You really think an intake on an LG4 produces 20 hp. I hope so, I'm using the stock intake from my LG4 on my 350 and I just got a new intake, waiting to be installed.

 

hrm, I think u guys are right about LG4 being a good engine as in durability, I meant a bad engine as in performance. I want to make my car a 400 hp beast, but thats gonna take a lot of money, tiem and effort. So Im prolly not goign to be able to do it, but I will be able to make 300 hp hopefully. then nos it or supercharge it :-) cheat to get tot he 400 hp range.

 

The LG4 wasn't good performance-wise because Gm made it that way. The carb 305 was a generic smog motor that didn't belong in the f-body with the POS heads, peanut cam, and manifolds it had. The 305 really gets an undeserved bad reputation because of that. When you bolt on decent parts just as gm should have all along, it definately responds well. On the other hand the LG4 is a very reliable long-lasting motor. I had 150K on my formula firebird when i sold and it didn't use any oil and ran strong. I know several people who have LG4 cars that have gone 250000 without removing the valve covers.

 

Yeah, it's been shown a number of times on dyno sheets in the mags that a Performer, for instance, will add 20 hp. Some claim a Performer RPM adds 40 hp.

 

IN response to Hg (cause I don't know how to insert someone else's remarks)...

Change oil 3 times (cheapest stuff)...of course at the end it was just adding oil as necessary. never changed trans fluid...except the time I mistakenly unbolted the trans cooler line and it went out everywhere. never changed rear end fluid.

The mechanic I and my father used never changed his oil in his trucks. My dad's trucks have lasted 30+ years and he only adds oil as necessary. He street raced a certain car over 400 times (327) without ever changing oil (just rearends). I have since broken that habit on my GTAs...
However, I abused the heck out of my 85 Trans Am...its a miracle it made it to 267K...I treated it like ****...gave it no slack.
A tribute to the LG4 in my opinion.

And the car still runs and drives today

 

I agree with everyone else with the durability factor from experience. I had an older Coupe with the lg4. At the time I knew nothing about cars or care for cars. That car literally was beat on daily,and had it's oil changed twice in 150,000 miles...no joke!
I thought it had good power back then,but understand the engine was rated at a pathetic 140 hp for a v8. I used to wonder why I could barely hang with the 85' 2.8 coupes. My carbed lg4 was alot bigger than the mpfi 2.8, yet my "big" v8 had only 5 hp more than the v6!

From my experience,the lg4 was a great,very durable and reliable block. That engine was obviously not designed with performance in mind,after owning a few Iroc's with the tpi lo3 or lb9...I see what a dog that lg4 was. The tpi lo3 or lb9's are monsters comparatively speaking,not only in hp but also in sotp torque...maybe not as reliable though.

 

Durable and reliable....yes.
Powerful...in stock form, not very. But they will respond well to small mods. The only mods I've done to mine are headers/catback and a small cam (.420" lift in/ex). I now have over 220,000 miles on mine; it starts easily, doesn't smoke since I've replaced the valve seals, still pulls down 24+mpg with a T5 and 3.42 gears.

Pete