I bought an '86 trans am (really rough, but I have good plans for it) that had an LG4 stock, but I'm doubting that the original engine is in this car. Anyway, can anyone tell me if the LG4's had black valve covers and aluminum intakes?

I tried to get the number on the back of the block, the one thats below the wiper motor on that little ledge, but I can only come up with a "5". There doesn't seem to be a "0" or a "7" to go with it. Any ideas on other accessible casting number locations?

Thanks everyone
Rex

 

An Lg4 car has an H encoded in the 8th letter of the vin. They had perimeter style valve covers that were usually black, and a low rise aluminum intake. I dont know anything about their block casting numbers tho. But other than that, I cant really make too much sense out of of Your question. What exactly are Your goals and what are You trying to accomplish here?

 

It looks a lot like every other small block with a carb on top. The casting numbers are the same as every other 305 of the same year, too.

 

According to the small block giude the only blocks with a 5 as a casting # for 1986 are as follows #366245 (350) #14088548 (350) #14088551 (305) and thats it if you want more info on casting #'s for small blocks (heads, cranks, pistons and blocks trywww.nastyz28.com/sbchevy/sblock.html

 

It's hard to even see the LG4 in my '85 IROC. It's covered with stuff!

 

"What does an LG4 look like?" A big black worthless pile of poop! Sorry, had to chime in, lol

 

the transition from blue to black was right about 82/83 year

in 85 86 black is correct though definitely

and 84 too

aluminum 4bbl spreadbore intake was correct on them all too,



what i think he means by the 5 and 0 or 7 is the 5.0 or 5.7 that they started casting on the bellhousing ledge later on

i dont think an 86 would have this, but some late ones might, ive never noticed it on any 86 engines ive had, including the 305 4bbl out of an 86 pickup i had not too long ago and snagged the 4416 heads and intake from


good luck

 

Correct. The 1982 engines were blue, while the 1983 and newer were painted black.

 

On my '85 LG4, you'd be hard pressed to even tell if the engine block is blue or black ... It's covered with hoses and things.

 

Remove the alternator and check the casting number on the block in front of the passengers side head. Decode the casting numbers at MorTec, Inc. Home Page. There will be two different sequences of numbers, one will tell you what the engine is, the other will have a partial vin with the production sequence number, if it matches your vin you have the original engine.

Carb cleaner, a fine wire brush, and a little patience goes a long way...

 

If you have the LG4, the best mods you can do are carb, intake, air cleaner.
this is what my 86 Trans Am LG4 looked like after I added those parts,


Car ran a best of 14.94 @ 93mph with these parts.

 

Wow, that's lightly modded TPI range... I didn't realize LG4s had any potential at all. What's the compression ratio?

 

Not to rain on your parade, but theres no reason to change the carb if its working properly, and changing the intake isn't worth it untill you do some other work first. The stock intake is quite good, and isn't any kind of bottle neck untill you change the exhaust system and cam first.

 

I wouldn't say best. Easiest, maybe.

 

Well, I swapped teh carb since it was the same price to rebuild the Q-jet, $219 for the Edelbrock 1406 carb.
I swapped the intake since it was only $100, Edelbrock 7101 Dual Plane Hi-Rise, and it allowed me to get rid of the square bore to spread bore adaptor plate.
Distributor was $60 I think, and air cleaner/filter was $70.

compression ratio on my 86 LG4 was 9.5:1 and was rated at 165hp. (according to the DATA on this site)

How fast does a stock LG4 run? Mine had 113K miles on it when I took it to the track.
this is the best ET, don't have the slip with the best MPH scanned,

 

Not shooting down what you did with your car Zepher, just saying that assuming everything is working as it should, most of those parts won't give much gain untill you change the cam and exhaust first.

 

Reminds me of the carb'ed 5.0 that I had in my '86 Monte Carlo SS. It really came to life when I yanked it and put a nitrous-fed 383 under the hood :-)

 

so, what you are saying is that if my motor was bone stock and running great, it would post the same times???
I had stock cam and exhaust on my car still.

also, my Formula with all the mods it has (minues the headers) can only muster up a 15.2@92mph.
I'll be taking the Formula to the track next month when it cools down a bit to see what the headers did for me.

 

Probably pretty similar, provided the stock parts were working correctly. You could have had some gain over tired, worn out stock parts, though.

 

I am with Zephyr on this one... There is no way even a healthy, low mileage, stock LG4 will run under 15 seconds. That intake and carb matched with a non cc distributor probably made a substansial power increase over stock, across the rpm range. Although it would probably take dead on timing and tuning combined with an ok gear ratio and sticky tires to accomplish that kind of et.

 

Not really. Recurving the advance would probably provide more benefit than the intake and carb. It's like widening your driveway because it takes you an hour to commute to work.

 

It surely didn't hurt its performance, but it wouldn't substantially help it either. The timing advance (assuming you have good gasoline) is easily the best bang-for-the-buck thing you can do under that hood.

I recall the shock on my buddy's face when I finally pulled him by a couple of car lengths, after losing to him for nearly six months. We had near identical '79 Z28s, but his was an Auto to my 4-speed.

A friend of dad's was a mechanic, and he introduced me to the wonder that is that little package of springs and weights. You could FEEL the difference in the way the car ran ...

Mike M

 

I had an 86 LG4 from a Monte Carlo in my 84 Z28... Edelbrock 1406 carb, Performer RPM intake, headers, 3" exhaust, no computer, etc... I ran 16's. No idea what was wrong. Maybe it was my 3:23 gears? I dunno. All I know is I got a TPI and never looked back! haha

Anyways, anyone could have changed parts on your engine. There is one way and one way only to see what it is, and that is the cast number under the wiper motor on the back of the block. Anything else is just speculating. And you can't go by the number stamped on the front, as people change those. I had a 69 350 that was stamped as a 65 327 on the front <rolls eyes>

 

That would match the LG4's redline of 4200rpm perfectly LOL!!!! TPI is garbage in my opinion. And by the way, I had an 83 TA with an LG4/auto, and 3.42 gears, TES, and a catback...and it ran consistent 14.9x at 91mph. Thats all that was done to it, stock CCC setup and all. All with a 3500lb race weight.

 

I'm not sure how you can say the TPI was junk... with all the extra torque and HP... not to mention way quicker throttle response and better gas mileage.

The LG4 is junk. Not worth putting money into, unless you don't want to pull the engine. Some people will say otherwise... but the majority will agree that putting bolt-ons on a crappy engine is futile.

 

If your goal is 14's, then the LG4 is fine. I would never settle for 14's. Im not saying youre going to run 10's NA. Its a good starting point for a mild street car if thats what youre lookng for. And TPI is junk. Yeah, they make good low end TQ, but I dont know where youre getting this extra HP crap from. NONE of my L69's ever lost to an LB9...ever. And they stuck with if not beat a lot of L98's. Sorry, I like to have a motor I can wind past 4,500 rpm without it falling on its face. TPI was decent I guess, but the design was all wrong. Replace it with a miniram, HSR, or ASR, do some tuning, then yeah...good to go. But in stock form, TPI is garbage, no matter how much you port the plenum, no matter what runners you use, no matter what base you use...its still garbage.

 

I don't see a problem with the carbed 305 engines, LG4 or L69. This is a LE9 305 truck engine, 175 FWHP/255 FWTQ, very similar to the L69. It was converted to TBI and had headers and exhaust. This is the stock 3.08 gears and P255/70/R15s.

YouTube - Van Burnout

 

Well, correct me if im wrong, but isnt the only real difference between the L69 and the LE9 the cam? Both have 9.5:1, same intake manifold...the LE9 has "601" heads, while the L69 had "416" heads?

 

Uh.. what?

 

Uh, what??? Im talking about MAJOR diffences between the L69 and LE9. The cam seems to be the only MAJOR difference between the 2 engines. The "601" heads and the "416" heads seem to flow about the same amount, with the 601's edging out the 416's ever so slightly. So let me rephrase that....The only major, measurable, obvious difference between the L69 and LE9 is the cam. Uh, what???

 

I consider heads a major difference... regardless of flow. That's like saying a Chevy head is a minor difference than a Ford head... if they flow the same.

No need to be a **** because you fear fuel injection

 

I dont fear fuel injection. I want you to tell me when I said that. I am a very big fan of fuel injection. But TPI is absolute garbage. Your comment about the head differences made absolutely no sense. The 2 heads listed flow the same, have the same valve sizes, same combustion chamber sizes, and are both perimeter style valve cover heads.

 

LE9 has 9.5:1 compression, although I calculated to be 9.8:1 compression (flattops 4 valve reliefs, 53 cc heads, steel shim style head gasket) 601 heads and "929" cam along with a different exhaust (2 1/4" exit manifolds, 3" Y pipe, 3" pellet box cat, 3" single in dual 2" out muffler.

The 601 heads flow about 5-7% better than the 416s, have a 462 style chamber that is 53cc and different spark plug placement. To get power out of either head requires some port work, larger valves, and some chamber unshrouding.

This is a picture of replacing the head gaskets on a 200,000 mile LE9 that had been converted to TBI about 50,000 miles before.



These pictures are what happens when you work in a machine shop and the boss and yourself get bored on a slow day. The final specs were 55cc chambers, 1.94"Intake 1.60" exhaust, 173 CC intake ports, guideplates, and .550" lift capability. All I can say is that with the Federal Mogul CS1014R that was in it, it ran great. It eventually layed down 198 RWHP with an untouched 454 TBI unit, 55lb/hr 305 injectors, and 305 prom chip in it. After tuning it with larger 61 lb/hr 350 injectors, it was 248 RWHP. I put these heads and the same used cam in a 355 TBI shortblock (10.3:1 compression calculated) and pulled 265 RWHP @ 4,600 with 340 RWTQ @ 2,800.

 

Fast355; Thats some good info you have listed there. I have 601's on my 84 MSE and was actually weighing out my options as im preparing for a rebuild. Id like to keep the numbers matching short block, but what are your suggestions as far as heads go? Would you say go aftermarket or work with what I have? Jusging by what you were laying down, im sure you know your 305's. Any pointers?

 

Very few aftermarket heads have ever been made for the 305. Most are out of production now. AFR at one point in time made a 190 head for the 305 that had the valves closer togather for the 305s smaller bore. I believe Trickflow makes a head for the 305 or atleast did at some point in time.

601s make great heads for a 305 when they are worked over. Another great pair of heads come on the ZZ4 crate engine. They are basically re-cast Aluminum TPI corvette heads that flow the better than the stock TPI L98 aluminum vette heads do. The ZZ4 heads have some material left for port work, although not alot.

23 Degree 175 Aluminum Cylinder Heads for Small Block Chevrolet

23 Degree 175 Airflow Chart, 3.766" Bore

Lift Value: Intake Flow
(CFM): Exhaust Flow
(CFM):

--------------------------------------------------------------------------------


0.100 61 53
0.200 127 105
0.300 180 142
0.400 216 160
0.500 242 172
0.600 242 180

NOTE: Tests conducted at 28" of water (pressure); exhaust with 2' pipe.

 

Thats kinda funny that you mention that. I have a picture somewhere of my stock 1983 LE9 (produced in 10/82). The engine was painted black over blue. It was originally blue, but repainted black, the black started to peel off and blue began to show through.

 

Thats interesting. Maybe it only pertains to thirdgens. But every 82 I ever owned was GM blue, while every 83 and newer was black. Kinda puzzling. Unless maybe some of the early 83's were still blue...I dont have the build dates for a lot of my early thirdgens handy anymore.