They can be a fun driver, they make a good amount of low-midrange torque with nearly no changes and still run pretty good for what they are.

The TPI exhaust bit depends on which TPI exhaust you use. Some of the LB9 305 cars had the same LG4/L03 exhaust manifolds and exhaust as a TBI car.

 

I think you would like the way it ran after I got my hands on it. Especially with some chip rework.

 

Right, I thought of that as I wrote it.

The 2.25" exhaust manifolds going into a 3" exhaust or the N10.

 

I would think that setup would run pretty well. The factory 93-95 G-vans had a 2.25 to 3" Y-pipe and slightly less restrictive exhaust manifolds. Despite using a non roller cam and turning a power robbing clutch fan while being tuned less aggressively (less timing/richer mixture) it was rated at 175 HP @ 4,200 and 265 TQ @ 2,400..

 

A neighbor has had an L03 Formula just sitting in the front yard for years now. This thread makes me want to knock on their door and see what plans they have for it.

 

That's a healthy sounding van!

 

I will definitely be checking to see if I have the 369 ICM and if I don't I will be purchasing one. See if that don't help it a lil.

 

So if a guy walks into a parts store (that's not the beginning of a joke), what do you ask for to make sure you get a 369 ICM? And, how can you tell that you DID get one? Is it stamped on the part?

Chazman...if I'm taking your thread too far off topic, tell me to take a hike, and I'll start a new one.

 

From what ive gathered AC DELCO part#10482827. It replaced #19179578 or vice versa..

 

If it is a factory module the numbers are stamped/highlighted in white on the face.

That being said the parts house junk ones are anybodies guess. I have tested a few and they are all over the board.

The one aftermarket I have had good luck with is the Davis Unified Ignition one. I had a good discussion one day with Tom aka Haulin@$$ and he also mentioned that he liked them as well. The latency was pretty darn close to a 369 module, except the dwell changes in the circuitry create alot more spark energy higher up in the rev range. I have turned a couple of engines 6,500 rpm without any noticeable misfiring with the DUI module and coil.

http://www.summitracing.com/parts/dui-000444/overview/

 

The easiest way to find a good 369 module is look in a late 80s/early 90s G-van.

 

Thanks Fast!

 

Also there is gold in this thread

https://www.thirdgen.org/forums/diy-...ncy-table.html

Particularly RBob's post and testing....Found similar results in my testing as well.

https://www.thirdgen.org/forums/diy-...ml#post3775917

More info
https://www.thirdgen.org/forums/diy-...n-modules.html

This was a testimonial reply I found in the above long forgotten thread.

 

Thanks! It ran great, I loved mashing on the go pedal in it.

It was really fun after I put a Vortec head TPI engine with a nice little Reeds custom grind cam in it. The engine was healthier than the pro "built" 700r4 that was in it. Couldn't keep one in it.

http://vid243.photobucket.com/albums...m/101_1468.mp4

 

No way, Dave. These are EXACTLY the kinds of nuggets I was hoping this thread would uncover.

 

I wonder how many L03 members were searching last night for "369 ignition"? I know I certainly was. First I have ever heard of that mod. Thanks, Fast!

 

Ha! Probably everyone who read the thread!

 

The 369 vs 048 ignition control module can be found in numerous applications other than a L03. Even the last of the LG4s had them. The TPI engines had them. TBI trucks and vans as well a Caprices and other B-cars. The biggest performance gain I have seen putting a 369 module in place of an 048 was in a 91 454 SS truck that had many bolt-ons and a hot spark advance curve in the chip. It felt like it had a small shot of nitrous added at about 4,000 rpm.

 

I could live with that. Well, that and an extra 149 cubes.

 

This has turned out to be an awesome thread!

 

Yea it has, alot better than what muffler or open element to put on my L03!

As irony would have it, I spent my Sunday working on the L03s younger, more powerful brother, the L30. Sorry for drifting off on a tangent but, a used L30 or L31 for that matter would make a great project to replace a high mileage L03.

What I found inside of this engine is typical of a well maintained L30 or L31 even at high mileage. With the sequential injection, modern oils, and relatively low cruising rpm they all seem to live very well.

I mocked it up in its new home, prior to tearing the shortblock apart.



250K on this engine, 200K in the the 96 G1500 Express it was born in and another 50K in my buddies lifted 98 K1500 truck that is rolling on 44s. He built a 383 and I got the 305 in exchange for a little tune work on his 383 build. I will have about $300 in it from intake to oil pan, water pump to flexplate and only have about $450 in the Astro and still have the rebuilt 4.3 that had never run that came out of it.

The L30 is getting a Lunati flat tappet cam because I had it.

268/268 @ .006
218/218 @ .050
.457/.457" lift
110* LSA
106* ICL

The stock L30 makes 220 HP and 280 TQ. I think the cam, exhaust, and tuning changes will put it up around 280 HP at 5,200 rpm and 330 TQ @ 3,500 rpm. It will probably only idle with about 12 in/hg of vacuum in gear at 550 rpm but the recipient vehicle has hydroboost and electronically controlled HVAC.

Block cleaned/honed with the 250K mile polished crank and new main bearings. If you look closely the cam is already installed and lobes coated in assembly lube.



New timing chain set and the original L30 reluctor installed for the crank sensor. I was going to change the freeze/core plugs but the factory ones appear to be brass and I feel they will last as long if not longer than the steel replacements I had. Also I keep hearing about how these "vortec" blocks lack a water pump coolant bypass port when every block I have had has had one. Its clearly present on this block. This block also has a mechanical fuel pump boss that was drilled and tapped and covered with a block off-plate, identical to my 97 L31 in my Express built in the end of 96. Building this engine or my L31 to replace a LG4 would be equally as easy.



Even at 250K the bores were still nice and round, with nearly zero taper. A quick hone has them ready for cleaned original pistons and new rings.



For 250K she cleaned up nicely with a little degreaser, elbow grease, and a trip into the jet washer. I am sure you guys can tell what is getting a L30 swapped in place of the original L35 4.3 V6.

 

I have talked to people that have put a Vortec in an astro and really liked the conversion, the one guy said he had to move his radiator forward a little to get it all in there tho..

 

Sure you are not talking about a S10?? Never heard of having to move a radiator forward in an Astro/Safari but I suppose anything is possible. The older body style I helped work on years ago we cut down the fan shroud, bent an a/c line a little for clearance and bolted a set of 2nd generation F-car headers on it and fabricated a 2.5" dual exhaust. It was a TBI 350 from a 9C1 and that thing would run.

 

Yesterday I checked out an '89 IROC-Z convertible with an L03, 5 speed, 3.08 gear. It drove so much better than the last L03 I drove, which was a '91 RS with an L03, auto, 2.73. In the IROC it revved smoothly to 5000 RPM and was actually fun to drive. I acknowledge that it had better gearing and a stick - but it was more than that, the motor had a different personality. Maybe it had the better ignition module or something?

BTW, here's the IROC's motor. I post this because I've never seen an L03 with the silver gray valve covers and intake before. I'm assuming the previous owner painted them, unless someone here tells me differently.

 

I've never seen an L03 in anything other than all black. What it does appear to have is a truck air cleaner lid....taller, allowing a larger filter.

 

Dave, you are right! I thought there was something different about the air cleaner, but I couldn't put my finger on it.

 

That engine appears to be OMC gray!

Also 2nd on the truck air cleaner lid.

 

The whole engine was painted the Gray... Or at least the intake was...

I wonder if it was a 350... I bet that would make for a nice driving vehicle, a stock Vortec motor...

 

GM actually made a variety of TBI fuel injected marine engines even prior to vortecs and the OMC marinized version was painted gray. Could have been a 305 or 350. The 305 version often had a flat tappet cam around 200/210 @ .050 and .400/.410" lift with the TPI 081 heads. The 350 version often had a roller cam around 196/206 @ .050 and .431/.451" lift. One version had cast iron 083/217 heads on it and the other L98 aluminum heads. The engine in the picture has pre-vortec heads on it as the vortecs 8 intake bolts are vertical.

 

The block and heads were black.

 

 

Do the L03 powered IROC's have speed limiters like the LO3 powered RS cars?

 

I believe so.

In contrast, I do not think (if it does not sure how it would work) the LG4 had a speed limiter. I suppose they could turn off the electric fuel pump. (My 87 LG4 had the tank FP and the mech FP.

John

 

I didn't think the LG4 had a speed limiter on it, at least I've never heard of that. I never did understand why they put the speed limiters in the higher performance cars with the LO3. I thought when they were new the cars with L03's came with Eagle GT tires just like the LG4 cars did so there shouldn't need to be a speed limiter.

 

I always assumed it had to do with the police... Didn't want the hoi-pelloi to outrun the poe-poe you know...

John

 

While I've never tested the top speed of my L03 powered cars, I'm fairly certain they are capable of high enough sustained speeds to exceed T or S speed rated tires.

 

My 1987 LG4 doesn't have a speed limiter and I know that for a fact.