Well, the time has come. I'm getting all my motor work done this week. Edelbrock Performer intake, Holley #1850 600 cfm. carb, and a vacuum advance dist.(to replace the computer controlled one). After that, I'm gonna remove the entire pollution control system, and the A/C, which has'nt worked since the early 90's. Anybody got some words of wisdom or advice? Oh and I'll be getting some Heddman headers in a few weeks. So any tricks or tips would be appreciated.

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---Grady---
1984 Berlinetta.
LG4 305, 150 hp.
Rochester Quadrajet(Comp. Controlled)
TH-700R4.
Flowmaster 80 series/ 3" cat-back pipe.
Accel Superstock Coil.
7.5 10-bolt rear/ 3.08's.
Edelbrock signature series air cleaner -w- K&N Filtercharger.
Pioneer head unit, Pioneer front 4X6's, Cerwin Vega rear 6x9's.
Daily Driver.

Personal Quote: "The Rice-Boys all tremble with fear when the old American V8 draws near."

 

Save the AC and fix it. You will be glad you did once it is hot in the car and besides, it uses very little horsepower when not engaged.

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1986 Camaro Sports Coupe
T-tops, power hatch, third brake light
LG4 305 V8, Q-Jet 4bbl
TH700R4 transmission
Air, pw, pl, pb, ps
Kenwood cassette, Pioneer component front speakers
Rockford Fosgate 6x9 Punch rear speakers
Aluminum slots and Goodyear 225x60R15 Eagle HP tires

 

Im used to it not working, so all its doing is adding weight, and cluttering up my engine compartment.

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---Grady---
1984 Berlinetta.
LG4 305, 150 hp.
Rochester Quadrajet(Comp. Controlled)
TH-700R4.
Flowmaster 80 series/ 3" cat-back pipe.
Accel Superstock Coil.
7.5 10-bolt rear/ 3.08's.
Edelbrock signature series air cleaner -w- K&N Filtercharger.
Pioneer head unit, Pioneer front 4X6's, Cerwin Vega rear 6x9's.
Daily Driver.

Personal Quote: "The Rice-Boys all tremble with fear when the old American V8 draws near."

 

Yeah, instead of wasting money on a new carb and distributor get a cam, you will see 10x the gain from a cam. The stock carb/computer isn't that bad for performance, and will slaughter the holley for economy. Even the intake is useless until you get at least headers and really won't do much until you get a cam in it. You wanted words of wsidowm, there they are. You are modding your car in the wrong order and you won't be happy with the gain (or lack thereof) if you do it the way you are planning.
...ed

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Ed Maher - Moderator @ The Carb Board
92 Z28 Convertible - Quasar blue / Tan top
LB9 4L60 GU2 G80 - stock, soon to be sleeper
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

Well, i am gonna do headers, but im really not wanting to do a cam swap on a motor with 130,000 miles on it. I think that will just be too much.

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---Grady---
1984 Berlinetta.
LG4 305, 150 hp.
Rochester Quadrajet(Comp. Controlled)
TH-700R4.
Flowmaster 80 series/ 3" cat-back pipe.
Accel Superstock Coil.
7.5 10-bolt rear/ 3.08's.
Edelbrock signature series air cleaner -w- K&N Filtercharger.
Pioneer head unit, Pioneer front 4X6's, Cerwin Vega rear 6x9's.
Daily Driver.

Personal Quote: "The Rice-Boys all tremble with fear when the old American V8 draws near."

 

The carb, dist, & intake are almost entirely a waste of effort until several other things are done first. Attack the actual deficiencies of the motor, rather than throwing away $500 by just bolting on easy-to-get-at popular replacement parts.

The LG4's first bottleneck is the exhaust system, all the way from the heads to the street. Absolutely nothing else you do will have anywhere near its full effect as long as any of that is still there. Put a set of headers on it first, preferably NOT ones that will bolt to the LG4 exhaust, because it's so tiny. Get ones for a L69 or TPI car if you get any that are made to fit a particular application. Again, unless you enjoy giving away money and getting less than it's worth in return, DO NOT buy any exhaust parts that are specifically for the LG4. Replace the whole thing all the way from end to end with 3" stuff if possible.

Next, that engine has the lamest, weeniest excuse for a cam that GM has ever come up with. It's even worse than the one that made 350s in the 70s only put out 165 HP. Put a good modern one in it, I would suggest either the Comp XE256H or XE262H, with the valve springs to match.

Next, port the heads. If you take one of those bare castings and look at the bowl right behind the valve, you will wonder how the motor ever even runs beyond 3000 RPM. You'll wonder even more how the L69 got 190 HP compared to the LG4's 145 (not 150) using the exact same castings.

Once you've done all those things, you might notice a difference from changing the intake and carb and dist. But even then you won't get the full benefit of whatever you do because you'll still only have 8.5:1 compression. The next logical mod would be to replace the pistons with flat-tops, but that's not cost-effective either. Basically if you do the above 3 things and it's not enough, you need to start looking for some other motor.

130,000 miles is nothing if the motor has been taken care of. That's not a good excuse for throwing away money on bolt-on stuff that will have little or no effect, and leaving the things that are the real obstacles to performance untouched.

BTW just to put the exhaust and cam thing into perspective, the differences between the L69 and LG4 are: L69 has 2¾" exhaust with 2¼" head pipes, LG4 has 2¼" exhaust with 2" headpipes; L69 has a cam with 15° more duration at .050" and about .030" more lift; L69 has flat-top pistons and therefore 9.3:1 compression, LG4 has dish pistons and 8.5:1; L69 has electric fan and dual-snorkel cold-air breather, LG4 has clutch fan and single snorkel breather that draws in hot under-hood air. The 2 engines have the same heads, intake, and distributor, and only minor carb differences.

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited July 03, 2001).]

 

I have an LG4 and I can assure you that changing the Qjet's rods and hangar had a very profound effect on the engine's performance! It is MUCH stronger now!

Likewise, adding the Crane vacuum advance and spring kit to my HEI ignition has given it another real kick in the rump. I'd be surprised if these two changes alone didn't shave 1 to 1.5 seconds off its 1/4 mile time.

Also, my 86 LG4 has an electric fan/rad setup from the factory.

And finally, the single snorkel does come out the front of the engine compartment, and thus does not simply suck in hot engine air.


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1986 Camaro Sports Coupe
T-tops, power hatch, third brake light
LG4 305 V8, Q-Jet 4bbl
TH700R4 transmission
Air, pw, pl, pb, ps
Kenwood cassette, Pioneer component front speakers
Rockford Fosgate 6x9 Punch rear speakers
Aluminum slots and Goodyear 225x60R15 Eagle HP tires

 

SB, I'd be surprised if they do. 1 second is a BIG change in power, not just a SOTP change. Doing all the things Ed & RB suggest might get that 1-1.5 sec reduction, though.

Trigger, you've been given sound advice here. Don't waste your money on the Holley & distributor. Do the real things first.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 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 & 3" cat-back).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).