L-69 305

[Copdogcorvettes]

I'm not sure if this is the right forum or not, but here is what I'm looking for: I has reading about RPO's and there was mention of the L-69 305 from Chevy. This is one that I have never heard before. My first Vette was an '80 with the 305 and I really like it; great mileage on the highway and still preformed very well.

I'm looking to build a new motor for my current vette; and I just happen to have a spare 305 setting in the corner. So, after seeing this L-69 thing I started thinking 200+ HP 305 may be fun. :L

So, does anyone have any information on this motor and if so what are the specs. I know I'm going to take a few hits on the idea of a 305 over the 350. But, an '80 305 was 180 HP and the '78 350 was only 185 rated.
Let the fun begin, I hope someone has something on the L-69.

Thank everyone for any help.

Gary

 

[Hib Halverson]

The L69 was a "high-performance" option in the mid-80s on Camaro and Monte Carlo. It was a computer controlled engine but could be converted to non-computer. It was rated at 190-hp, I believe.

It was never offered in the Vette.

 

[Copdogcorvettes]

Thanks Hib, At least I have a place to start looking for specs. Do you know anything on the heads or cam that was used?

Gary

 

[KANE]

I'm not sure if this is the right forum or not, but here is what I'm looking for: I has reading about RPO's and there was mention of the L-69 305 from Chevy. This is one that I have never heard before. My first Vette was an '80 with the 305 and I really like it; great mileage on the highway and still preformed very well.

I'm looking to build a new motor for my current vette; and I just happen to have a spare 305 setting in the corner. So, after seeing this L-69 thing I started thinking 200+ HP 305 may be fun. :L

So, does anyone have any information on this motor and if so what are the specs. I know I'm going to take a few hits on the idea of a 305 over the 350. But, an '80 305 was 180 HP and the '78 350 was only 185 rated.
Let the fun begin, I hope someone has something on the L-69.

Thank everyone for any help.

Gary

L69 cam data-

GM P/N 12523897

I- 294 @ Lash Point
E- 294

I- 202 @ .050
E- 206

I- 403 Max lift @ 1.5 rockers
E- 415

Lobe Center line 115


Technically, the L69 cam is better than the GM Goodwrench replacement cam. So it is also a bigger cam than the OEM LG4 cam.

From the specs I've seen so far, the L69 cam is identical in terms of design to the TPI cam. The only difference is the L69 is designed for flat tappets and the TPI cam is designed for rollers.

 

[Copdogcorvettes]

Darkshark thanks for the cam data on the L-69. In a way you are right on the LG4. I liked that motor and thinking of building a 305 by using the L-69 & LG4 parts to come up with around 200 or so HP. Should be able to mate MPG, HP and driveability in a C3 4speed package.

Gary

 

[Hib Halverson]

(snip)

L69 cam data-

GM P/N Crankshaft Duration at lash Crankshaft Duration at .050 Max lift w/1.5 rockers Valve lash Lobe centerline 12523897 I- 294
E- 294 I- 202
E- 206 I- 403
E- 415 Zero Lash 115

Translated that's
294°/294° intake/exhaust duration at .006-in lift
202°/206° duration at .050-in lift
.403/.415-in lift at zero lash
Intake center line is at 115°.

In short, it's a pretty mild cam, but typical of mid-80s 305 stuff.

I'm not sure what cylinder head was used on the engines but it's gotta be something pretty mild, in fact, it wouldn't surprise me if it was the same head used on LG4s.

 

[topless82vette]

L-69 aka 5.0 h.o ... 416 heads, flatops, 9.5:1 compression, 3 inch exhaust, 3 inch high flow cat, electric cooling fan, richer secondary metering rods, 36 degree total advance verses LG-4's 32 degrees, I think the performance difference between the two engine was more related to the L-69 getting 3.73 gears verses the base 2.73/3.08.

now as for economy you are barking up wrong tree my old 84 t/a with that combination was good for maybe 16 city 23 highway.

now my 1990 TBI ex L-98 engine easily gets that and runs circles around a H.O. This 90 engine was a 1990 vette shortblock with 89 f-body 350 TPI heads, stock vette cam. It's mated to a T-5 with 3.73 gears, in short more power and better economy.

and a L-69 only made 190hp. But I would say that was over rated because I once raced a 1985 mustang GT with the 210hp 5speed and that car slaughtered my 84 trans am. I bought this 84 t/a brand new and it was a turd so don't have any high hopes for economy or performance from building a 305 like it.

 

[Copdogcorvettes]

Well as normal I'm getting a lot of good information from everyone. To give a little more info. : My '78 vette is a L-48 4speed with 3:73 rear gears. The motor is stock from the factory w/except for Holley 650 spreadbore and '69 style sidepipes. The MPG is 12 - 15. The only options are A/C and 9 leaf rear spring w/rear sway bar; there's no power anything. It just handles and sounds great. It's just a nice driver with '91 cloth seats and an '80 style rear bumper. I just want a good drivers that looks & sound good. With the stock 350 only rated at 185 hp 180 t0 200 hp 305 should be easy to do and get hopefully 15 - 20 mph. That why I'm looking into the 305 HO specs.

gary

 

[topless82vette]

Well as normal I'm getting a lot of good information from everyone. To give a little more info. : My '78 vette is a L-48 4speed with 3:73 rear gears. The motor is stock from the factory w/except for Holley 650 spreadbore and '69 style sidepipes. The MPG is 12 - 15. The only options are A/C and 9 leaf rear spring w/rear sway bar; there's no power anything. It just handles and sounds great. It's just a nice driver with '91 cloth seats and an '80 style rear bumper. I just want a good drivers that looks & sound good. With the stock 350 only rated at 185 hp 180 t0 200 hp 305 should be easy to do and get hopefully 15 - 20 mph. That why I'm looking into the 305 HO specs.

gary

what about going with a hopped up LO-3 TBI 305. The swirl ports would give you nice lowend torque and wiring up tbi wouldn't be that hard. Or why not run later TBI on your L-48?

 

[mcditalia]

My first car was a 1984 Z-28 5.0 H.O "L-69". While the car brings back great memories, the thought of 190 hp seems weak by todays standards . Although it did have 240 lb ft torque at low revs.

The motor had a lot of parts that were directly lifted off the Corvette parts bin. With some tinkering you shouldn't have any problems reaching your goal. Although you could probably get better results from a 350 TPI of the same era and get the same gas mileage.

 

[yenkoguy]

I just noticed this thread so I'll a comment. The L69 became the optional "hi-po" engine in the 1983 Z28. I bought one brand new from Burt Chevrolet in Denver. It was definitely faster than the base model, or the "tuned port" option cars then available. It was more than competitive with the Mustang GT's until 1986 I believe. Then it was blown away by the much lighter car. The "computer controlled" carburetor was nearly impossible to deal with especially with the high altitude emission package from Colorado. I solved my performance needs by trading it in on a Buick GN....end of Mustang competition.