[PetesPonies]

its a carb engine. I'm not familar with these engines or these cars at all. What are the problems to look for on these cars? What are good mods for these engines.

[77Y82W72]

Pete,

Since it's a carb engine, you can do pretty much any type of SBC you wish if you delete the computer-controlled Q-jet. I've always considered the carb cars prime candiates for a Pontiac V8 swap. With any engine, a true dual exhaust requires a lot of extra effort due to the rear torque arm arrangement. Early transmissions and rears are pretty fragile (later ones are a little better). The 3rd Gens are good handlers (later ones are better with WS6, 16" wheels, etc.). A front brake upgrade should be at the top of your list of to-dos.

Look for rust in the lower fenders, rockers, door bottoms, & lower quarters (especially if it has GFX). Front shock towers & underside of rear hatch around spoiler mounting holes can rust out too (just like a Mustang). Since they're unibodies, look for cracks in the roof/B-pillar at the rear top corner of the side windows. Most have them, sub-frame connectors can solve this. Essential if it has t-tops.

The best place on the web for 3rd Gen specific information is:

http://www.thirdgen.org/techboard/?

Best thing about 3rd Gens is that everyone thinks they are slugs. If you make one fast, you have an instant sleeper that every import in town (and alot of older American iron too) will go out of their way to pick on. Both my Formula and GTA are magnets for Hondas with coffee can exhausts and nothing else. Truely the Rodney Dangerfield of "collectable" cars. I've never raced mine against each other, but stock-for-stock I think both of my 89s could run with or maybe take out my 68.

Good Luck, Have Fun

[Dens71TA]

There where two carb engines offered in 1983. The base 150HP LG4 and a High Output 190HP L69 became available around March 1983. The 8th digit in the VIN will tell what engine it originally had(H=LG4, 7=L69, S=LU5 Crossfire) The '83 L69 engine came only with a 5-speed manual and had higher compression, high lift camshaft, larger exhaust, 3.73 axle ratio, revised PROM calibration and Electronic Spark Control, and electric cooling fan.

The drivetrains are pretty reliable. Common rust problems are in the lower cowl and inner rocker panels. The floor boards can rust out at the front seam where the cowl and main floor panels meet. The frame rails are pretty good on these cars. The strut towers can rust out but the rest of the car will have to be already very rusty before that happens. The rear hatches typically leak at the sides and the spare tire well can rust out in the back.

A stock LG4 will benefit greatly with an upgrade to L69 or mild aftermarket parts. The biggest thing choking down the LG4 is the "peanut camshaft" and small exhaust. Upgrading to a stock L69 or computer friendly camshaft will make a pretty big difference. The stock LG4 cam makes it hit a brick wall at 4000 RPM. Installing L69/TPI large outlet exhaust manifolds and 3" Y-pipe or headers along with a good 2.5"-3" exhaust system will help it breath much better. Modifying the carb with richer secondary metering rods and filing the secondary air flap stop so it opens all the way will net a noticable boost on the top end even with the stock LG4 cam still installed. A performance PROM will do away with the ridiculously conservative distributor timing table in the stock LG4 PROM. This may not allow you to run 87 octane fuel anymore since the LG4 computer and wiring harness doesn't allow the addition of the ESC and knock sensor that the higher compression L69 has. Installing an electric fan will free up about 10HP and net about a 1MPG gain but will require a higher amp alternator.

If its one of the rare '83 L69 cars its pretty maxed out the way it is. In stock form the L69 cars are surpisingly quick and were still faster than the early TPI cars that replaced them. About the only upgrade to do would be headers and a slightly better camshaft. The PROM could probably be worked over a little bit too.

If this is a LG4 car without WS6/WS7 its going to have something like a 2.73 axle and most likely not be posi. Swaping in a 3.23-3.73 ratio axle from another 3rd-gen will greatly improve accelleration just by itself.

Resist the urge to DEEP SIX the computer carb and distributor system. The only thing the computer controls is the primary metering rods and distributor timing. With the secondary system richened up and some performance minded timing table settings in the PROM there is no reason you couldn't be putting out around 220-250HP and getting 25MPG going down the highway.

[PetesPonies]

sounds very good guys. Unfortunately the car I'm looking at is a lowly LG4 engine, but has only 46K miles. Its been garage kept, pretty clean car. Thanks

[77Y82W72]

Originally Posted by Dens71TA

In stock form the L69 cars are surpisingly quick and were still faster than the early TPI cars that replaced them. About the only upgrade to do would be headers and a slightly better camshaft. The PROM could probably be worked over a little bit too.

I think this is very true. Back in the day, a co-worker of my dad's at the local Chevy dealer had a brand-new white '83 MCSS factory freak. That stock L69 ran with and often beat early TPI F-bodies and carbed 5.0 Mustangs even while carrying around the extra weight. Usually wasn't even close against other (and newer) MCSSs. Car was a "lightweight" with practically no options.

Upgrading the LG4 to lightly-modded L69 specs should give you a fun driver, especially if it's a stick.

Basic differences between LG4 vs. L69:

http://www.chevyasylum.com/tech/L69vsLG4.html

If you can get it for a reasonable price, grab it!

[PetesPonies]

back in the summer of '83, I was working for a rental car company ( new teacher ). I went and picked up some new cars, a few were LG4 Camaros. I drove one that was fast. It just moved like the others didn't. It even barked as it shifted from 1-2 and if I remember right, I got a slight bark at the 2-3 shift once. But the 1-2 was consistant. Not being a GM person, I always remembered that car )

[1968_Catalina]

i had a 86 iroc camaro before my catalina , make sure that the floors aren't rusted out . my car was a t top car and i could touch the carpet from the underside