are they any good, can they keep up with 350s if not what mods can you do to 86 lg4 to keep up with some fast cars.

 

Without tearing into the short block, you can add anything: cams, W/P 305 torquer heads, intakes, headers, mod the E4ME, K&N, advance timing (the lower CR keeps things from knockin'), etc ...

I seriously believe, with a proper setup, the LG4 short block can see 13s NA.

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George P. Lara
1994 Z28 LT1 T56
1984 Z28 High Output
Member: SCCA, SCFB, SC3GFB
Chevy Info --> MadMike's

 

With the mods in my sig, I have gotten my 86 LG4 powered 86 Trans Am to run in the upper 14's. This is a motor with 133K miles on it without a rebuild.

I have a pic of my slip at my website, http://www.leannrimes.cz28.com

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Zepher
'86 Pontiac Trans Am WS6, 5 Speed:
Edelbrock 1406 Carb, Edelbrock Performer RPM 7101 Intake Manifold.
Edelbrock Open Element Air Cleaner: Flowmaster Exhaust, 160* Thermostat,
Grant GT Steering Wheel, MSD HEI Coil, Taylor 8mm Wires, Recaro Seats,
Alpine CD+Changer,Rockford & Soundstream Amps, Premier TS-1040C Subs, Polk Audio highs/mids.

WS6 Trans Am

 

I converted my LG4 to TPI, and the heads, bottom end, and exhaust manifolds go untouched, and I turned a best of 14.97 @ 94.9, so the base engine is capable of putting out, you just need to work on intake/exhaust mods. The Q-Jet probably won't get you there, you will probably have to step up to a better carb, and a matched intake.

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If you live in Southeastern US, check us out!
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ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
JET AFPR,
Ported Plenum,
TB Coolant Bypass,
SSM SFC,
Boxed LCAs,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
KYB Shocks
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

The LG-4 suffers from the same basic, inherent problems as the later cars with the TBI "low output" 305. Those problems are:

1. Low compression ratio (8.5 or thereabouts)
2. Weak cam. REALLY REALLY weak.
3. Choked up exhaust system. 2" outlet manifolds and 2 1/4" exhaust from the cat all the way back.

All fixable, but not with just a few quick bolt-on parts.

Fortunately, with the LG-4 the carb is NOT a big restriction (unlike the TBI motors that DON'T have a good flowing intake).

 

The stock lg4 is rated at 145hp and the HO is about 190 I think. With bolt on mods on my old lg4, I almost broke 15 seconds. It is really a weak and pathatic motor for a v8. Go for the 350. Besides, a new 250hp 350 is cheaper than the new lg4.

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1983 Camaro Z28
Goodwrench 350ci V8, Edelbrock TES Headers, Flowmaster Catback, MSD 6al and Blaster 2 coil, Edelbrock Performer intake, Edelbrock Performer 600cfm carb. T5, 373 rear, Eibach springs, Cervin Vega speakers, Rock. Fos. Sub, Pioneer CD,
email-chris4421@hotmail.com
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"I used to be a Mustang Guy! I didn't know the power of the dark side!!"