chazman

iTrader: (4)

Why the 1987 LG4 is superior the previous LG4s:


1) Roller cam
2) 081 TPI heads
3) 9.3 to 1 compression
4) single main seal
5) center bolt valve covers
6) 170 hp @ 4400 RPM, 250 ft/lbs @ 2800 RPM.
7) 3.23 gears with manual trans.

chazman

iTrader: (4)

The '87 LG4 is exactly an '87 peanut cam LB9 with a carb and smaller exhaust - and better gears.

dmccain

iTrader: (2)

Never really seen the use in GM putting what seemed like a dozen different engines in these cars. In 93 all v8s were 350s and LSD rear ends. This is what they should have done years before. Like 1982 before

chazman

iTrader: (4)

Yes. The combinations of engines used on 3rd gens is mind boggling. Even when they used the same code.

The 1987 LG4 is a different engine than the 1982 LG4.

Fast355

iTrader: (2)

GM made like 5 different L05s as well. Changed depending on application.

dmccain

iTrader: (2)

Should have just made L98 longblocks to use in trucks and cars.Better roller cam design and a lil better heads. L98s work well with TBI just a lil more fuel and timing

skippermatt

and the 1985-1986 LG4, having flat tappet cams, and also flat top pistons, are different than the 1984 which has dished pistons, and 1987 with a roller cam. So many different engines in these cars.

chazman

iTrader: (4)

I guess you could say that 3rd gens had three LG4s. '82-'84, '85-'86, '87.

Fast355

iTrader: (2)

Roller cam yes, L98 heads, NOPE. The trucks were better off with the swirl ports. The swirl ports make more torque under 4,500 rpm using less fuel and less timing, allowing them to run on cheap 87 octane pump gas. Then again I would have used the aluminum L98 heads on the trucks. They allow for more timing and compression even on cheap fuel and they make more torque than TBI or Vortec heads.

Tom 400 CFI

I can't believe this is a topic worth talking about, but true, the late LG4 is...."better".


Saaaaay WHAT!?

Where did you locate that "data"??? Let's review:
L05 head more tq than L98, below 4500? Though, we know that L98 makes more HP (at and certainly right below) at 4000-4500.
L98 Vette heads make "more tq" than L05 heads (that I agree with!) or Vortec heads. (?) At which RPM?

So...the 113 head is the "king ****" of all junk yard gen I heads?? Why are so many people wasting their time with heavy, iron Vortecs, then!?

Tom 400 CFI

~$150 at the u-pull-it yards....

ENGINE (NO ACC) 208.99 Each 45.99
ENGINE BLOCK 114.33 Each 24.99
HEAD CASTIRON NO CAM 43.19 Each 5.99

TEAR-A-PART

Fast355

iTrader: (2)

Through dyno testing, having an 8.75:1 1-ton TBI 350 Goodwrench crate engine, the 8,600+ GVW one thats part number ended in 20270 that is no longer made. Started out with 810 swirl ports. Then moved to 113 heads. Then moved to 906 Vortecs. Up to about 4,500 rpm the 113s and 810s had more torque than the 906 Vortecs, all 3 setups running a ZZ3/ZZ4 cam at the time. Those were the good Canadian OE Vortecs off the 350 in my 97 van that grenaded at 57K from hydraulic lock too. I had the heads gone through and they eventually went on that engine. The crappy Mexican 062s that came on the Goodwrench replacement engine in the 97 van made that engine a complete and total dog. Not even kidding when I say that engine was down 40 hp compared to the 57K mile OE engine that hydraulic locked from bad intake gaskets. The 906s flowed 242 @ 0.500, increasing throughout the lift curve to 0.530. The Mexican 062s peaked 218 @ 0.450 then fell to 210 @ 0.500. The Mexican heads cracked in less than 30K, at which point I put Etec170s on it. That engine had a mild cam and headers by that point. The Etec swap gained ~40 hp at the tires compared to the 062s. That was with the OE L31 truck manifold which I later replaced with a L31 marine manifold. I ported that L31 marine manifold and it currently resides on the 210cc aluminum heads on the 11:1 383 I replaced the 350 with. That engine makes ~550 ft/lbs @ 3,500 on E85. I would not put a penny in a Vortec head now. I used the last good set I had that were actually thicker deck aftermarket Vortecs on a L31 I recently built with a LT1 rotating assembly. I had already fitted those with LS6 springs and Comp 787 retainers 5 or so years ago. I recently shoved that L31 into a 1987 G20 van to replace a LQ4 with Lloyd Elliot ported 862s and about the smallest truck cam made. The 6.0L was more gutless than a stock TBI 350 with headers and tuning under 4,000 rpm. With a TH400 and 3.08 gears the LQ4 was always dropping to 2nd gear to climb even a small grade. The wimpy 6.0L could not push 4,500 lbs up a 6% grade at 2,500 rpm. The TBI 350 even with the stock cam in my heavier 1983 with a 700r4 and later on 4L60E had no problem making it up the same grade and held overdrive all but a steep 1/4 mile long section, where it would briefly pop down into 3rd. Then it would shift back into 4th and keep on going. 1983 had the same 3.08 gear and same size tires. My 97 at 7,000 lbs does not even unlock the converter going up that grade with the 383 chugging along at 2,200 rpm. 4L85E + 3.73 gear in the 97.

QwkTrip

iTrader: (22)

I see Tom and Fast355 showed up to yell at each other, it's the spiral of death for this thread.

Fast355

iTrader: (2)

Not my intent at all. If I had one of those later 87 LG4 cars, I would throw 113s on it using the GM 0.028" compressed L31 head gaskets after sending them to Lloyd Elliot, put the ZZ4 cam in it, Dyno Dons headers and keep the CCC Q-Jet on an Edelbrock Performer RPM Q-Jet manifold. I would put a set of DR metering rods in it maybe even CEs, then experiment with the base timing up from 6° to about 10-14°. It would be a fun car especially with a 5spd or a S10 converter and 3.42s or 3.73s behind the 700r4. That would be a solid 325-350 hp 305 that still ripped in the midrange.

chazman

iTrader: (4)

Actually, I enjoy reading both of their posts.

Tom 400 CFI

You should post those dyno graphs. Where are they?

dmccain

iTrader: (2)

I am still in firm belief Vortecs are far far better than swirlport heads, 113 L98 heads, 083 heads... Watever stock head period.

chazman

iTrader: (4)

I'd bet adding HO exhaust manifolds, N10 exhaust and L69 aircleaner, would add 35 horsepower to an '87 LG4.

MY87LT

iTrader: (2)

I installed SLP headers with A.I.R. tubes, a single 3 inch catalytic converter with a 3" intermediate pipe with a dual 2.5" exhaust. I also have installed the L69 air cleaner with the taller Monte Carlo lid for a larger air filter. How much power did I gain? Who knows. Never took it to a dyno. But...it does perform better than it once did when I first got the car. I've read so many articles and people with guesses on these particular upgrades. Some say I went from 165 hp to anywhere between 190 to 210. Just the way it is without better valve train I would guess 185 to 190.

skippermatt

I did a similar exhaust system with a cam, intake manifold, and carb to one of my cars when it had a lg4, great little engine, didn’t feel like a race car or anything but at the same time didn’t feel slow. was great when that car was my daily at the time.

87WS6

iTrader: (1)

I think the TPI system would have been better in the trucks than TBI from a performance standpoint. Low end torque is what you want in a truck. The toilet bowl only won out because it was cheaper to produce.

On the topic of the LG4, I had a 1987 LG4 car and its by far the most reliable and least problematic thirdgen I've ever owned.

dmccain

iTrader: (2)

I had an LG4 in an 87 Formula. Ran 15.8s stock. We put full 3 in exhaust, a mild cam, edelbrock intake and holley carb on it. It mustered a 14.8, not as good as i thought it should do but definitely 60-70hp upgrade.

chazman

iTrader: (4)

Auto or stick?

dmccain

iTrader: (2)

Auto and very sucky 2.73 gears i suppose

chazman

iTrader: (4)

That's actually pretty good. My SOP, (seat of the pants) meter says that my '87 LG4 Formula, 5 speed, 3.23, "feels" like a mid-high 15 second car.

dmccain

iTrader: (2)

At the time I thought it was OK but then i bought a 91 Z28 Auto 5.0 TPI car and bone stock except 3 in exhaust and cat delete it tripped 14.76. Bone stock 305 so then I was like wow, all that work and the stock TPI car was faster..

MY87LT

iTrader: (2)

Yes and Yes. The LT V-8 package didn't allow for manual shift. The only thing I could never confirm was the availability of limited slip for the LT specific.

I'm still keeping the automatic but going with a monster transmission instead of rebuilding my own. And dropping in 3.42 gears.

dmccain

iTrader: (2)

3.42s will be perfect! A 2500 or so stall would be a great addition. I have an S10 TC and it really made a difference. About 2400 stall

BBCSwap

You might want to read the reviews.

Tom 400 CFI

If that is what actually happened, I'd suggest that the "more tq" from the 113's came from?....more compression. Change the piston for an apples comparison and I think you'd see different results. No way any stock swirl port made more anything, than any Vortec above 3.5k. By 4500?? Not happenin'.


The rest of this thread is fun reading...makes me recall my LG4 days and improvements that were made. We didn't know squat back then, and good heads didn't really exist....so it's fun to look at it again from today's perspective and it's pretty obvious what needs to be done, and where the value is.

Fast355

iTrader: (2)

113s added torque is from compression and from port velocity. Those 163cc intake ports are efficient at lower engine speeds.

The Vortecs were down till 4,500 compared to swirl ports. I really do not understand why so many people knock swirl ports, never have and never will. I have gotten over 320 hp without porting them multiple times with relatively mild cams. It is easy to make over 400 ft/lbs of torque at 3,000 rpm with swirl ports. Vortecs take a bit more engine speed to make up for their slower burn rate. TBI heads only need 26-29° total timing, which means that there is less negative work on the crankshaft at low rpm. The improved breathing of the Vortecs does not come into play until the 4,000+ rpm range. My stock swirl port head, stock cam 350 TBI made peak hp at 4,600 rpm and carried good power to 5,200.

chazman

iTrader: (4)

Exhaust and air cleaner easily brought it up to L69 power.

Tom 400 CFI

Compression.

So let me understand this. GM made a 350 that made power until about 4000 - 4500. 230-250 hp. That would be the L98. They ended the L98 in '93, and did a revised truck engine in '96 with different heads and intake and a smaller cam....basically. That would be the 255 hp, L31 with new/updated cylinder heads. THAT engine also made it's peak HP at 4500 RPM.

It sounds like you're telling us that GM replaced a shitty head, with a head that makes less tq (and power) from 0-4500 RPM. That's what you're telling us? Does that make any sense at all? No, it doesn't...and that's because that isn't what happened. GM came out with a head that makes more tq (and thus, power) from ~ idle, to 4500 RPM.





Help me understand this. GM made a 350 that made power until about 4000. 190-210hp. That would be the L05. They upgraded the engine in '96 with heads and intake....basically. That would be the 255 hp, L31 with new/updated cylinder heads. THAT engine made it's peak HP at 4500 RPM. Right? Right.

So....you're telling us, that GM replaced a shitty head, with a head that makes less tq (and power) from 0-4500 RPM. For and engine(s) that operate from 0-4500 RPM? That's what you're telling us?? Does that make any sense at all? No, it doesn't...and that's because that isn't what happened. GM came out with a head that makes more tq (and thus, power) from ~idle, to 4500 RPM....and that is why that head, is so universally praised and sought after for Gen I engines. Say anything otherwise is ridiculous.


To be clear, then, you're telling us that GM made three, 350 engines that made peak hp at ~4500 or less; the L05, L98 and the L31. Your claim is that the older of these engines, had heads that "made more tq up to 4500", than the newer of the three designs....but somehow, these same older engines had a lower hp rating at 4500! How does that work? How does an engine make the same tq at 4500 as another engine, but have a different hp rating, at 4500? Can you jot down some math to show us how this works in Fast355 world?



I'd like to hear more about this too...please. The L31 head is a "fast burn" combustion chamber...the L05 head is not. More engine speed on a "slow burn" head would equal less tq...not more. Talk about this....would you?

This stuff is rich.

Fast355

iTrader: (2)

The L31 has a fast burn chamber, however the TBI heads have an even faster burn speed than the Vortecs. I add timing to every Vortec head TBI that I have ever tuned, not take away timing. The Vortec head swap still has a low-midrange torque loss. Anybody that has ever run both heads on the same vehicle after tuning both for maximum output knows this. It took me adding a GM 6395 camshaft to a L31 to get as much torque as a stock cam L05. Both made a touch over 300 ft/lbs at the tires with headers and tuning. The stone stock L31 made 250 ft/lbs at the tires. Cam, 1.6 rockers, Tri-Y headers and tuning added 54 ft/lbs for 304 rwtq @ 3,400 rpm. Stone stock L05 long block with 1.6 rockers, performer rpm manifold, 454 TBI unit and tri-Y headers made 308 tq at 2,800 rpm. HP was 229 and 208 respectfully. L31 peaked at 5,100 and the L05 peaked at 4,600. I put a 96 LT4 cam in both at one point as well. The TBI made 250 hp @ 5,000 with the LT4 cam. The L31 made about 280 hp @ 5,500.

GM revised much more than the cylinder head on the vortecs. The camshaft is smaller, the exhaust is higher flowing and the port fuel injection flows better than a standard SBC TBI unit.

If you noticed, I never said any of these setups were stock either. When you start changing things like the intake manifold, switch to headers, open up the exhaust and tune them, that is when power curves start to exceed the OE rated numbers and RPMs.

For a more direct comparison, I also did a TBI head to Vortec head swap on a TBI 350 in a truck. This is nothing new, I documented it years ago. From memory I kept the 350 TBI unit, stayed with the same style GM TBI intake manifold (stock TBI manifold with TBI heads and a stock 96 van TBI manifold with Vortecs) kept the same shorty headers, kept the stock cam, kept the 1.6 roller rockers, kept the same exhaust. All I did was tune each for maximum power. The L05 TBI heads made more torque on less timing than the L31 heads. The crossover point was right at 4,500 rpm. The TBI heads made more torque until 4,500 rpm, then the vortecs walked away and made about 20 more hp up at 5,500. I would say more than half of the Vortecs rated power difference and ALL the added torque in stock configuration comes from the better EFI setup, sequential port fuel injection, cam timing changes and exhaust changes. The head flow change only really benifits higher RPM. Dewey316 made a similar test with his TBI 305 around the same time. His 187 TBI heads outperformed a set of nicely ported 416s until ~4,500 rpm as well. L31 vortec heads on that combination would have caused him even greater torque loss.

The 4.3Ls got weaker when they went to the 96+ vortec configuration. The earlier 92-95 CPI engines wiped the floor with the later Vortecs. They had more torque, more hp and better fuel mileage in the CPI configuration. I have owned an Astro van with both engines.

Fast355

iTrader: (2)

Since some people believe they do not exist as well, this is a 96 G30 and Marine style factory GM TBI L31 manifold. They both used 2" bore TBI units from the factory. The vans that I have seen with these had the fold forward style hoods. Basically a P30 chassis with a van cab. The G30 van setups all had the RPM governed throttle bodies like the 366 and 427 tall deck TBI engines.



Governed 2" TBI for reference

Fast355

iTrader: (2)

As far as where are the old charts and what not. I lost something like 700 pictures and loads of videos from that time period when Photobucket axed my account because I did not feel like paying their extorsion to download or keep them in place. When they put bandwitch limits on old established free accounts, blocked access to remove the files, and wanted to start charging relatively large sums of $ for me to keep my account open, I basically made the decision to let them close the account. I lost even more data and information when the old Car Domain site folded as well.

Tom 400 CFI

Three posts of BFS.

Fine job avoiding the crux of my question about your bogus claims, but I'm still left wanting: How do three engines make the same tq at 4500, but have different HP ratings at that same RPM??

This is dumb and I can't believe I'm wasting my time with all of the Gwhatever van-story bullshit that isn't accurate, no data....all stories, ....but think about this:

Paraphrasing, you said that 113's and Swirl ports make more tq than Vortecs, up to 4500. Right? Right. That would imply that Vortecs make more tq above 4500....right? Yep. From that, one can deduce that 4500 is the crossing point where the tq from a Vortec passes the tq from the 113's and the Swirl Ports....thus, they're all making the same tq at 4500 RPM. According you what you posted. THEREFORE, since we know that hp is a mathematical function of tq and speed, if we're making the same tq at the same RPM....we're making the same hp. Right? That's right!

Unfortunately, in this discussion, we're talking about three engines that actually make different hp at 4500 RPM....so, it's also mathematically impossible for them to be making the same tq at that RPM. So based on that alone, it's very easy to see that you're spouting BFS. Beyond that, there is so much more that makes no sense (the part about GM make a less powerful/tq head for a later engine that makes more power at and below 4500??) So, the claim that you made is bunk, on it's face, and a pretty untenable position to take over all. Van stories and pictures of boat parts don't make story-time, any more believable. Sorry.

Fast355

iTrader: (2)

Apparantly you are just dense. As I said the crossover point is 4,500 rpm. Below 4,500 rpm the swirl ports make more torque. After 4,500 the Vortecs make more torque. Obviously at 4,500 rpm they made the same tq and same power. You are comparing 3 different OE engine configurations rather than looking at what you can get out of the same long block and combination changing only the heads. In your scenario, all 3 setups have different cams, different intake setups and different exhaust. If you took the same 350, put the same style dual plane intake, same camshaft and same exhaust system on them the comparison I posted is valid. As I said before swapping the cylinder heads only was my comparison. I also gave you two other combinations as a reference points. I even went into great detail on how the cams, intake setups and exhaust were different between a L05, L98 and L31. In fact you fail to even realize that in the way you are looking at the comparison a L98 makes more torque than a L31. Put a TPI intake on a L05, open up the exhaust and it is going to make more midrange torque. Put a TPI intake on a L31 and it too will make more midrange torque. If you could bolt a LT1 intake to both, they will trade torque for more RPM. Dual plane intake is going to do what a dual plane intake does. Single plane is going to act how a single plane does, etx.

Fast355

iTrader: (2)

Tom,
I have a legitimate question for you as well. If newer supposedly means better in every way from a GM casting, why is it that your 113 heads kick a 2001 LS1 to the curb in terms of torque? Your Vette Kart is making within 10 hp of a vastly superior on paper LS1 with a factory LS6 intake manifold. It is making its peak power earlier and making far more low-midrange torque. Even with a torque less mini-ram intake manifold your L98 was making more torque than a 2001 LS1 Corvette. This is a typical LS6 intake manifold equipped LS1/T56 Vette.



Your own dyno results for comparison, yet the 113s are garbage in your own words because they are far inferior to Vortec heads. Therefore, I also deduce by your own logic that Vortec heads are far inferior to LS1 heads. It seems to me that the 113 heads have a pretty good handle on making great low-midrange torque.

T-Ram vs. TPI, Dyno Results.... - Page 2 - Third Generation F-Body Message Boards

Tom 400 CFI

Yeah....that's the "problem" in this discussion. I'm the "dense" one, here. Right.

They don't.

But you should definitely keep telling yourself that! Try not to contaminate the rest of this forum with this dog-****, though.

Fast355

iTrader: (2)

They absolutely DO and the only one putting BS in this post is YOU!

I have built and tuned enough combinations to understand what does and what does not work for various goals.

An LQ9 6.0L does not make as much peak torque as you saw from your L98 with an intake swap.

dmccain

iTrader: (2)

Ive seen several stock Vortec engines with nothing more than a spring kit, a mild cam swap, and carb put thirdgens in the high 12s. Same thing done to an L98 would be mid 13s at best. The 113s arent much better than the 083s. A bit better on exhaust side and lighter but not a great head like the Vortec.

Fast355

iTrader: (2)

I have plenty of ZZ3/ZZ4 swaps put these cars in the mid-high 12s as well. The old emissions legal ZZ3 swap put a car I know of to a very low 13 (13.08 IIRC at like 103 or 104 mph) with the CCC Q-Jet and factory exhaust manifolds. GMs own test car ran a 13.83 with no chassis/traction/gearing change modifications as well. That car was begging for more traction and 3.73 gears.

The 113s used on the ZZ4 outflow the Vortec heads. Especially the Mexican garbage ones. GM made some improvements on the ZZ4 version of the 113s. I did a little more work to a set and made 423 hp from a 305 with them.

Back to the same comment I said before. The L98 production heads make more torque while the production Vortecs make a bit more power talking factory production units. The mexican vortecs, Hecho en Mexico 062s also sold over the counter by GM Performance suck, they peak at 218 cfm @ 0.450 and fall to 210 cfm @ 0.500. Comparing the GMPP Vortecs to the GMPP ZZ4 113s, the 113s are a better head. Lingenfelters ported 113s flow in the 270 cfm range.

Tom 400 CFI

Sure thing bud. Still waiting on that Math, from ya. You know what math is....right? :bigears

Tom 400 CFI

YEP!


My god, the rubbish. I can't believe this forum tolerates it.

How do two motors make the same tq at 4500 but have different hp at 4500? Come on, man. Math it out for us!

Fast355

iTrader: (2)

Where did I ever claim that? Please provide the actual quote where I said that, because I did not. You seriously have a reading comprehension problem!!! That or you keep comparing GM SAE power ratings vs the results of an actual head swap that I actually performed. You cannot compare SAE power ratings of a L05 vs L31 and get the power change from swapping heads alone. Nobody ever said either engine had peak power at 4,500 rpm. Nobody ever said either engine made more HP at 4,500. That was the crossover point where the Vortec heads started performing a bit better than TBI heads on the specific engine I tuned and dyno'd. The only one this forum does not need in rubbish is you. You want to argue for the sake of arguing. Even though I even used your own dyno results comparing 113s against a stock LS1. Please explain that one as well. Your in your own words garbage 113s are handily handing a stock LS1 its butt in torque.

Airwolfe

iTrader: (1)

Wow you all sure ruined a thread about the 1987 LG4 engine.

B*tch about this Sh*t in PMs to each other. No one here gives a flying F*ck about who has the biggest E peen or is the biggest *****.

Tom 400 CFI

Thread was ruined when someone started a thread about the most "superior" LG4.

Got worse when someone started in with the BFS and made-up "math".

chazman

iTrader: (4)

Yeah, but that IS the thread. And generally an interesting topic worthy of discussion - especially on a 3rd gen site. All those 1987 changes added up to a better performing base V8 than the top of the line performance V8, 5 years earlier.

chazman

iTrader: (4)

Yes....imagine a 1987 LG4 in an '82 Z28. It would have killed the Mustang GT in it's crib.