Can ya guys help me out here?

Can someone tell me what the differences are between these two?

I know they are both 305 and the L69 is carbed, LO3 TBI'ed.

Other than that, what's the difference?

TIA,



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Tommy Raia
1988 Formula 305 TBI/WS6/A4
Third Gen Haven | My Mods

~Your stupidest thing for Y2K: Giving everything to someone who is not what they say~ - ¤Actual horoscope¤

 

The L69 has a much better cam, a better exhaust, and its not TBI
Compression ratio might be different, I'm not positive.

 

The L69 has better heads and came with 3.73 gears, in addition to the other things.

The L69 was the top-of-the-line performance motor of its day, whereas the TBI was the base-model V8, hardly more than a grocery-cart setup. It was not intended by the factory to be a performance setup at all, even though it can be made to be better than they made it. TBI motors came with a whole host of actually performance-hostile features.

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

 

I'm just talking strictly about the engine here..

So it came with better heads and a better cam, that's it?

As far as the exhaust goes, it would be an aftermarket set-up, so I'm not worried about that.

How hard would it be to mimmick an L69 using an LO3 block then?

(I'm home on Workers Comp and bored. Too much time on my hands.)

 

I think it's gone around that the 305 HO heads were a myth, ad that L69 heads are the same as Lg4 heads, leaving the main differences to simply be a better cam, air cleaner, and bigger cat/exhaust. It also had a hotter ignition curve in the 'puter than an LG4 and i'm sure an LO3, As well as the 3.73s.
The problem you;ll have in trying to duplicate it is teh same one that everybody with a TBI is fighting around here. In general TBI just doesn't want to go faster.
ed

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Ed Maher - Moderator @ the Carb Board
85 Z28 - 357c.i. - stolen 12/24
Click Here for the Rest
'83 Grand Prix - low miles
Only mods...Homemade open element, 2.5" cat and exhaust, CK-B metering
and the way out ******* style in effect
stock 14" wheels w/ wire hubcaps in front
snowflake 15" alloys in the back

 

Well, if and when my financial situation gets better, the ol TBI is going out the window.

My baby will be sporting a carb sooner or later.

Thanks for the replies.

 

L69/LG4 heads are not the same as TBI. TBI heads are "swirl port", the others are not. L69 and LG4 do have the same (416) heads.

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

 

Ed, if I may expand on your post about the heads (you are correct). In the 3rd gen F-bodies, the LG4s and L69s had 416 castings. But back before the 3rd gens (pre-'82, maybe '83, dunno exactly), the LG4s did in fact have smaller intake and exhaust valves (1.74,1.4?). This of course would cause some confusion.

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George P. Lara
1984 Z28 High Output
Proud Member of SCFB
V6 T5 For Sale

 

hey tommy..you responded to my hood article with the scoop. i appreciate the picture. i am located in great kills on staten island. and also where did you get that metal fencing for your hood?? i like that....and also do you ever have a problem now that it is opened when it rains??,,,respond under one of my posts in here or e mail me at caizzo44@aol.com......thanx tommy

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88 Firebird Formula WS6
305 TPI 5 speed
B&m Ripper shifter
MSD Blaster coil
TPIS airfoil
Hypertech fam switch
TPIS 170 degree thermostat
15.5@91.18

 

Has anyone seen a dyno for a stock/near stock L69? Because I have a hard time believing the cam, compression, exhaust, and heads are only worth 20 hp. In the TPI cars going from the same cam as the L69 to the the peanut cam (also in the L03) cost 25 hp by itself w/ nothing else different. Doesn't seem to add up. So you take a cam worth at least 20+hp, throw in more compression, better exhaust, etc, and the engine output is only 20 hp over the TBI? I don't think so.

Besides that I've heard people state the L69 was underrated, which wouldn't surprise me as the TPI engine needed to be a big enough step up, at least in the ratings (215hp at introduction), to get people to be enthusiastic about it.

Even more, I've heard from a few people who hit mid to high 14s in stock L69 cars (given it was a 5spd 3.73 car). And I don't see anyway a stockish TBI even w/ the 5spd and say adding 3.73s would run that or really even close to it. Anyway, something there doesn't add up...

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

 

TBI was the base-model V8, hardly more than a grocery-cart setup.

as a matter of fact i have the grocery car setup, and i live in memphis as well, so you name a place and i will show your ol heap a good time.

 

I guess I am one of the L69 examples - see
signature.
When I back calculated RWHP from the dragstrip data and car weight it came out to 215 (rear wheel!)

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Tom K.
84 z-28 M5 305 HO
pulleys,coil,3:73(stock)
Jet StageII, fan switch
14.55 @ 95.02 2.15 60ft

 

"as a matter of fact i have the grocery car setup, and i live in memphis as well, so you name a place and i will show your ol heap a good time."

As a newbie, you should be a bit more careful. RB wouldnt even bother racing your TBI car, its not worth the effort with a no contest race like that.

 

Lets see...I also used to have an L69 in my Z. The 215 RWHP that was quoted is correct from the factory. It is under rated though, due to easily obtainable HP with little or no money involved. You can do some "cheap" tricks to the carb to get some WOT HP. I had a 5 speed, and could take most 350's with just a K&N, and some carb mods. As a 305, it is a great performing engine with reasonable gas mileage too. The heads are the same as the LG4, but are better both intake and exhaust port wise than the LO3 TBI heads. The cam for the L69 had a higher duration and lift than the others for those years. Can't remember the compression ratio off hand though??? I have seen time slips of stock L69's running a high 14, to a low 15 1/4 mile at the track with a 5 speed, and having owned one...I believe it. I swapped mine out with 200K on it before I made it to the track. It is still running in an SS Monte in Nebraska.

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1984 L69 Z28 with 350 H.O., Hypertech ThermoMaster Chip w/ 160* PowerStat, Stock L69 Dual Air Intake w/ K&N, L69 Dual Plane Intake Manifold, Modified Q-Jet, 350 4 bolt main w/ Crane Energizer Cam & 1.5 Roller Rockers, Lunati Drop Forged Crank and Rods, 23 Degree Trick Flow Heads, Hooker Comp Headers, 3:73 Posi, T-5 (Soon to be a T56!), 4-wheel disc brakes, 3" Catback Exhaust...etc.

Wise man say....Man who jump on bedspring this spring....have offspring next spring!

 

Hey bubbz,

Thanks for the invite, we may get the chance some day. I seriously doubt you'd like the outcome, except that it's always fun to race whether you win or lose. I don't generally lose much, especially not to 302 Mustangs or 305 F-cars, but I've had some good times losing to a couple of race cars and bikes.

What part of town are you in? What does your car look like? I live near Summer & Graham, my car is a silver (fairly good paint, not original) 83 HO Z28 with 87 16" IROC wheels. If you're ever around there maybe we'll see each other.

If you ever get around to learning how to build motors (not just rebuild stock ones) you'll know exactly why I feel as I do toward TBI, regardless of its theoretical possibilities.

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

 

Tommy, don't bother trying to mimic an L69. Just get World 305's, better cam, better exhaust, and you'll be miles ahead.

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82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 3.08 open, cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress.
57 Bel Air, my 1st car. Currently 396 .030 over, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.