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I understand that it is underpowered. I knew it was unnderpowered when i bought mine i had a 92 before the 92 i have now and i knew it was weak. I searched for a year for my car and had to fly up to ohio from nebraska to get it.It was the perfect color and had t-tops and it only has 26000 miles it ahd 22000 when i bought it. I bought it because i love the car they look awsome and are neat cars. So why not just be happy you don't have a v6 and build it up a little and when the motor goes drop in a 350
Good point, at least we have v8's. Look at the 4th geners. So many of em have v6's. They make more hp than our cars but not tq. Ide rather have a weak v8 in a camaro than a nice 3800 v6.
This has become just another one of "those" threads. Nobody is talking about Artic Whites dyno pulls anymore.
I think i can sum this all up.
LO3 is a weak motor.
Mod whatever the hell you want.
scott i completly got ur point. U where trying to make the L03 sound bad by saying that todays 6 cyls have compareable #s. I countered that by saying the 6 cyls have compareable #s to todays V8s. So whats that have n e thing to do with n e thing. one is a 6 and one is an 8. compare the #s between the 2 all u want but i would be able to do the same so that was a sencless point. what about the the 542 hp V6 found in the jaguar XJ220. Becouse that makes more power than the lamborghini V12 (497hp) does that mean the V12 is crap?? no i didnt think so. U see where i am coming from dont u?
But like Kevin said, in the 80's nothing had great power like today.
Well, my 89 Taurus SHO put out 191whp at the wheels with a KNN and Dynomax Exhaust. 184fwhp bone stock. That's a 181 cubic inch 6 cylinder.
BTW, I think modding an LO3 is cool. These 305's can perform if your willing to spend the time and money to do it.
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1998 Z28
12.79 @ 110.29 - With no muffler, Drag Radials, and free mods (That's all!)
SAE Corrected 346rwhp 354rwtq with Mac Headers, UD Pulleys, B&B Triflow Catback, and Direct Flo Airlid
one other thing to consider is a new timing chain. they do stretch over time which retards the cam timing and costs you power. they are pretty cheap and esy enough to do in your driveway with instructions from any chiltons type book.
lata
tim
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91 Camaro RS-LO3,Auto.
14.390 @ 94.99mph
Edlebrock TES Headers, Cat Eliminator Pipe, Borla Adjustable Cat Back,Marche Pulleys, HyperTech Chip,Transgo Shift Kit,B&M Convertor(2000stall), 36mm Front 25mm Rear Sway Bars, Eibach Pro Kit Springs, Bilstein Shocks and Struts, Steve Spohn Rear Rig( all rod ends), Poly Front Bushings, Baer Track Kit Front Brakes W/ Baer Disc Rears, 17x9 4th Gen SS Wheels, Ported TB, Edlebrock Performer TBI Intake, Performer Heads, 1.6 Roller Tipped Rockers
How can you run that hypertech chip with those mods. I tried a chip from the TBI guy and ran like **** and my hypertech barely ran too
The car has Bosch +4 in with about 16,000 miles on them.
Gimmicky junk. If they're working, I wouldn't scrap them...but I'd not buy another set of 'em.
Originally Posted by Arctic White 91 RS
Do copper plugs make a better/hotter spark?
Not much difference. Very minor.
Originally Posted by Arctic White 91 RS
Should I try a set of AC Delco RapidFire 44's or 45's? At what gap?
Whatever plug you select, make sure it can be gapped at .040--.045. Not more than that. The side electrode is sized for a limited gap range, plugs intended for .080 will not work well with the gap crushed down to .045.
"I" would be unlikely to spend extra for "Rapidfire" plugs. I would install whatever GM specified, or the NGK or Autolite equivalent--or the variation of that plug that allows a .045 gap.
Originally Posted by Arctic White 91 RS
The Dyno operator said usually Autolites (Ford plugs) are worth a few horsepower over AC Delco's. Any thoughs on this?
Autolite hasn't been owned by Ford since Fido was a pup. Ford plugs are "Motorcraft". Which, by the way, used to be a Chrysler brand. Ever heard of Chryslers being called "Mopars"? MOtorcraft PARts = MOPAR.
I've liked Autolite plugs. Nice hard, long-wearing electrodes, unlike, for example, Champion's soft, fast-wearing electrodes and brittle porcelain. But then the folks who own the Autolite brand moved production to China, so I started buying NGKs, mostly.[/QUOTE]
If this were me--and it isn't--before I blew another fifty bucks for a dyno trip, I'd check cranking compression on all eight. I'd verify that cap, rotor, and plug wires were all in good condition, AND THAT THE PLUG WIRES ARE ROUTED THE WAY GM INTENDED paying special attention to numbers 5 and 7. Yes, this is a real pain in the ***. Yes, you may save yourself (and the engine) because #5 and #7 can inductively cross-fire, which will spark #7 90 degrees advanced--and that will ruin your day.
I'd verify fuel pressure UNDER LOAD. I'd verify that the throttle opens fully--misadjusted throttles are surprisingly common, in part due to the gas pedal lever bending.
I'd connect a scan tool, and take a heavy-throttle test drive, looking for any anomalies in the data stream, paying particular attention to short- and long-term fuel trim, O2 readings, cross-counts, and knock-sensor activity. Depending on how adventurous you are, you could try advancing the timing if the knock sensor doesn't object. Don't go overboard. Two degrees at a time, probably not more than six degrees total. And of course, you'll burn "premium" fuel during the tuning and during the dyno test to keep the knock sensor happy.
I'd drizzle a "urine-stream" of water--about a gallon altogether--back-and-forth between the two throttle plates of the TBI unit, with the engine running at 2000 rpm and fully warmed-up. This should remove all soft carbon in the combustion chamber, and maybe some of the harder deposits. May want to change oil afterward, but at minimum assure that the PCV system is working properly to draw the moisture out of the crankcase.
Disconnect and plug the vacuum source for the heated air intake in the air cleaner snorkel (if using a stock air cleaner assy., and assure that the heat riser valve in the exhaust manifold opens fully.
Trick Flow super 23 175cc heads, race level .600 lift roller cam, roller lifters, shorty headers, and a high rise 4bbl intake system = about 365hp at the crank. Add some dome pistons and shorter head gaskets (mind your dynamic compression ratio with your chosen cam), you can get up into the 400's. Higher and youll need forced induction, unfortunately. I think Super Chevy even has an article on either an LB9 or LO3 block bluid with dyno sheet numbers in the article. By far, the worst power killer on the 305 is those damn spiral port heads. It cant breathe with all the emissions ****, and the stock cam isnt helping things. They do however make a nasty 334 stroker engine. Some have done a 349 with an 3.875 crank and .030 bore, but you have a ton of grinding and clearance issues to go that high on them. Unlike the 5.7 block, the 349 strokers make huge torque but not as high on the horsepower. For a 334, you do a 030 bore and a 3.75 inch crank. Add some dome pistons, a cam to match and keep the dynamic compression at 8.5:1 (usually comes out roughly to 11:1 static, but dont look at the static and think that indicates a given dynamic compression, as that takes math with the cam, and it changes based on your engine config), some 195 CNC port and chamber heads with something close to .650 or .680 lift and good flowing ports, silicon aluminium bearings with an anti friction pro-plasma nitride coating, lightened rods, as small diameter of a balancer as you can get away with on your rotational balance (good balance pays off in a few extra horsepower up top because its not fighting itself or having to turn a heavy 8 inch balancer), long tube headers (if you can fit them), a billet aluminium flywheel, high pressure high volume pump, and batch port injection with tall runners that has injectors rated at 650-750hp, and you can get to a 600 crank hp, naturally aspirated. I built one in highschool for my Formula with my old LO3 block with the help of a retired builder that made engines for the local sprint cars at the dirt track. It did 596hp at 5800rpm. this was 17 years ago and I dont remember the RPM on the torque, but it was at 535tq at some point along the graph. 600 is about as high as we were comfortable going, so no forced induction, because this was a 2 bolt block and even with ARP studs on the mains, thats really starting to push your luck if youre doing launches on a prepped track with slicks. They can be mean blocks if you build them properly. However, the same level build on a 350/383 4 bolt (with bigger heads obviously, and slightly higher compression with 110 octane to support it - good E85, or oxygenated 110 race fuel) these guys are 750hp out there, naturally aspirated, at pretty much the same cost. So if you have a 305 and want matching numbers block in the car, or its sentimental, then build it. Otherwise just get a 5.7 block somewhere and you'll have more fun. If you don't want the 305 block and the engine still spins, send it to me, I'll give it a good home
Well seems like ~ 21 years later it's time for an update being that I'm the OP.
Never made it back to the dyno with the L03. The car did get a tune up and ran a bit better. Later an SLP Dual/Dual catback was installed. Apparently it sounded better as someone at AutoZone heard the exhaust and wanted to know what all had been done to the 350...lol
The original 305 LO3 TBI proved bullet proof. When the RS was LS swapped in 2015, the L03 had ~389,500 miles on it. Drove the RS 800 miles to Hawk's Motorsports for the restoration and swap. The RS averaged it's normal 30+ mpg for the whole 800 miles It's still my understanding it's the highest mile 3rd Gen that's ever driven into Hawk's Motorsports for restoration with an entirely original drive line without any rebuilds.
In 2012 or so the LO3 got a set of valve cover gaskets and that fixed the only oil leak. Mechanic was positive it was a ~40,000 mile crate motor based on condition...lol. He even argued with me the motor had to have been recently replaced given its overall condition. If not by me then by prior owner. He was speechless when I explained I'm the original owner, bought the RS with 9 miles on the odometer.
Ended up keeping the old L03 and it sits on an engine stand in my garage. Several friends have 3rd Gens so my old LO3 serves as our back up motor...it's still leak free.
The white RS dyno 465 whp & 442 wtq after the LS swap and now has a T-56 & 8.8 rear end.
I'm happy with the now 400,000+ mile RS 😀
For a while I had another 3rd Gen...Black Echo that's also in the picture. Also a LO3 A4 2.73 gear car....after tune up...Black Echo dyno'd 125 whp and 200 wtq.
The 72 Vette mentioned, ended up with a Dart 400 and hopefully will see the paint shop soon.
Last edited by Arctic White 91 RS; Nov 4, 2021 at 08:05 AM.
It's still my understanding it's the highest mile 3rd Gen that's ever driven into Hawk's Motorsports for restoration with an entirely original drive line without any rebuilds.
