What the heck is the difference between these 305's?

Why does the LG4 suck sooooo much,
why is the LO3 not as good as the LB9??

I know that the TPI has a little something to do with the LB9's advantage.
Is is cam profiles? Heads? All of the above?

Any info would be greatly appreciated!

(looking into finding a motor for the RS)

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http://kiztope.50megs.com

92 Rs 3.1/T-5
Its slowly but surely coming along....

AIM : Theonekiztope
ICQ: 8787542
Planetarion: 3GFB kiztope of kiztopia-Camera-92RS-A (33:6:14)

"If it can be better than it is, make it so!" Leon Calrinsky (00)

 

Don't know much about the LG4, but the difference between the LO3 and LB9 is mostly due to fuel delivery (TBI vs TPI)...maybe slight differences in exhaust manifolds and cam

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92 Camaro RS LO3, 5-spd, T-tops
Performance:
SLP 1 3/4" Headers (Coated by Paul Barry Motorsports), Flowmaster Catback Exhaust, Fastchip Performance PROM, Centerforce Dual Friction Clutch, Xact 8mm wires, Open Air Element w/K&N Filter, Z28 Grille w/aftmkt fog lamps
Electronics:
Alpine 8030 Alarm System, Valentine One Radar Detector (How did I ever drive without one?), Pioneer DEH 7450 Head Unit w/6-pack CD changer, Pioneer DEQ 7600 Sound Processor, 2 Kenwood KAC-846 Amps powering 2 12" Pro Red subs, 2 Pioneer 6x9 and 2 MTX 4x6 speakers.
NEXT UP: TBI mods, Edelbrock performer intake

 

the Lg4 is only rated at 145 hp i believe becuase of these reasons, very restrictive air intake, small camshaft, 8.5 to 1 compression, very small exhaust manifolds.
I think it was designed more for economy than performance.

 

'86-'87 LG4 had the higher compression and put out 155 hp.

You left out L69.

LG4: carb, low compression, restrictive exhaust and air cleaner, lame cam, low hp.

L69: carb, higher compression less restrictive exhaust and air cleaner, better cam, higher hp.

LO3: LG4 w/TBI (basically).

LB9: L69 w/TPI (basically). T5 LB9's had a better cam than automatic LB9's.

Heads the same on all, except some LO3's have swirl port heads (yuck). '87-later have center-two intake manifold bolts at a different angle.

But, you said it from the beginning - all of the above. Then some.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat).
57 Bel Air, my 1st car. 0.030 over 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlock header mufflers, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere w/open diff & slipping tranny.

 

The cheapest 305 to buy, and the easiest to put in and get good hp out of is actually the boat anchor of the group, the LG4. With a good aftermarket intake, mild cam, and headers the LG4 will put out around 240-250 hp easy and the cash outlay will be minimal. Not a bad choice if you are on the cheap and have to get a 305. I would definitely try to steer you toward getting a 350 though, even if it is relatively mild for now. Because you're switching engines anyway and you'll be much happier in the long run w/ a 350...

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Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

 

Its all about the LG4 baby.

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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver
Reader's ride -> My Ride

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

Seriously man do not mess around with a 305. A 350 is simply a superior motor in every way. 'Rebuilding a 305' should be an oxymoron.

That being said... the later LG4s and the L03 are roughly equal in performance. Low 16s in the T5 cars, mid 16s in the 700R4 cars.

The better LB9s (87-89 T5 cars and all 90-92 cars) are closer in capability to the 350 TPI than the other 305s. The small cammed 86-89 305 TPI auto cars are high 15/16 flat cars. The difference in performance vs the TBI and LG4 cars is due to better cam profiles in the 305 TPI, better heads, and (usually) a better exhaust, as well as the better flowing TPI unit itself.

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91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

Built on Wednesday

[This message has been edited by MrJ (edited May 01, 2001).]

 

<font face="Jester" size="+2" color="blue">LG4's rule!!</font>

Pete

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Pete's Place
HiOutput Tech Page

<a href="http://www.hioutput.com/pete/garage/83SC/83sc.html" TARGET=_blank><IMG SRC="http://www.hioutput.com/pics/SC.gif" TITLE="Pete's 83 SC" border="1"></a>
My 83 SC...(originally V6) 206,500 mile LG4/5-speed from an 84 Z28, 3.42 one-tire-fryer, T-tops, PW, PH, boxed LCA's, Hedman Hedders and y-pipe, Dynomax cat-back, .420" lift cam, custom air induction .....best ET is 14.935@94.14</P>

</P>Success means you got up one more time than you fell....

 

Don't forget the '87 LG4. 170hp, roller cam, one piece rear main seal, last year for the Rochester Q-jet. A very nice little reliable motor!

 

The LO3 and LB9 heads are acctually quite different.

 

The LO3 and LB9 heads are acctually quite different.

I have 2 friends, one has an 88 IROC LB9 the other an 89 RS LO3, both manuals. My friend with the 89 RS converted it to TPI, has full exhaust, SLP cam and 3.73 gears. The one with the LB9 88 IROC has full exhaust, 3.70 gears, and a ROD 6 speed. The LB9 IROC can wipe the floor with the RS, and both are TPI and modded closely. Now, I know the 6 speed in the 88 IROC helps out, but the heads on the RS have to be different. The IROC runs high 14s and the RS runs mid 15s, both up here at 6000 feet of course. So, the LO3 heads have to be a good deal worse than the IROC heads.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

Soon to Come: 7.625" 10 Bolt with 3.42s and Accel TPI Intake Base

 

Yeah I gotta say I believe the 305 TPI would run way better than high 15's/flat 16's. Probably high 14's/low 15's. I know Monte Carlo SS's had 305 HO's with carbs and they run mid 15's stock.