Alright, heres my problem.. Its really starting to bother me by geting left behind by the 4th gens (v6 even..). So what can I do to tune and mod my sleeping beast? I've got a new 305 with an Edelbrock Performer intake and stock q-jet. I've got an edelbrock 650 cfm carb laying around that I'm going to try and put on there this weekend. Please help, I don't like seeing tail lights..

 

Edel makes a 650?????

I'd get full exhaust first, headers and a cat-back. What cam is in the "new" 305?

 

yea i think ive heard of them making a 650 not sure though.... it might be older.

 

now that i think about it, i'm not to sure if its a 650, could be a 600.. i pulled it off a second gen in the junkyard, so i have no papers for it.. i don't even know how to tune the thing are there some kinda id #'s on it somewhere? i'm not sure what kinda cam is in the motor, i'll look in the paper work in a few min and see if i can find anything. as for the exhaust i'm saving up for some super comp headers and duel 3" pipes that dump just before the rear axle, cut outs just after the headers and no cats (i know its overboard for a 305 but i plan on droping in a blown 427 in around 3-5 years)

 

On the front left of the carb there should be 4 #s.

My 600 has 1406 on it, I think that's the #s.

 

i've got 1405 then just to the right of that (about a 1/4" to the right) there are more numbers 0275

 

this thread depresses me

 

why's that?

 

I assume 3rd gen V8 losin to a 4th Gen V6.

 

oh, yeah... well, hopfully if won't be that way for long

 

i doint know if its that depressing about him getting smacked down by a 3.8, especially if its been modded. Those 3.8's could give any stock 305 a run for its money. Whats been done to fully utilize those 305 cubic inches? if you dont have many mods and you have the stock heads it came with, youll continue to get shot down. If you do have some mods, then its an issue of getting it all to work together properly.

 

What rear gears do you have in you Z28? Reguardless of headders, cam, carb and other performance stuff a good gear ratio will beat those mods hands down.

 

as far as i know the rear end is stock, and so are those v6 4th gens i was up against (figured i'd add that for anyone that was woundering)

 

I hate to be the bearer of bad tidings, but I guess I have to.

You're going to continue to get "smoked" by V-6s of all varieties until you start to do something about it. Bolting on more or different parts isn't the thing that you need to do, or at least not yet. The first thing you should do is to get in, under, and around your car with a notepad, and start getting some information about it. Record all the RPO codes. Those will yield data about the engine, axle, springs, etc. Get the casting numbers from the engine case and heads. While you can't immediately change the parts, you'll know a little more about them, the most imortant of which is what you have to work with. The head casting numbers are important enough to spend time removing a rocker cover. If you've never changed the camshaft, chances are that no one else has either, so we can presume it is stock for whatever engine code you have.

And it doesn't matter whose carburetor is bolted to the intake. A well tuned Rochester 4M will flow up to 850 SCFM, so changing brands isn't the answer. Moreover, the Rochester will be a better street carb, since the primaries are much smaller and metering is more controlled in most normal driving.

Put down the wrench and pick up a pencil.

 

I have an 84 Z in the driveway covered with snow, why? Because I did the same thing. Here's what I have:
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350
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Edelbrock Performer RPM intake
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Edelbrock 1406 600cfm carb
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Milodon hi-flow water pump with 4 core radiator
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Vacuum advance distributor
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MSD wires with Bosch plugs
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The list goes on. I still have no clue why the thing ran 17 seconds at the track, maybe it's due to the T5 or the 3:23 in the rear?
Ahh well, moved it aside for a tuned port, what a difference!
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Wish you luck on it, possibly try to swap out the rear?

 

Vader got there first, I'll just restate that the carb isn't the performance problem. Putting an Edelbrock on would be a very poor decision from a $'s/performance standpoint.

Aaron, as for your 350 running 17's, there's a problem somewhere. You didn't mention cam, heads, or exhaust, but I suspect all three are contributing to a bad mismatch. The RPM intake is one hint of a mismatch. My little ol' 305 runs 15's at 5800' elevation (actual density altitude was over 8000' when I ran it). So, a 350 with better gears and manual tranny should do much better than that (at what I assume is a lower elevation).

 

I have an 84 Z with an L69, 3.73 gears.

Now I've added a few things, but not added exhaust of heads and my car is pretty respectable.

I did slap a 600 cfm edelcrap on there, but only 'cause my stock carb crapped out on me. Not to mention I upgraded the ignition system got rid of all of the emissions stuff (it was that or replace it all) and added a cam.

The 305 gets a bad rap, but I don't know that it deserves ALL of it.

I found that in my 84 Z, I am out of room, so a large dual plane intake won't fit. The stock intake manifold isn't so bad, in fact I've heard that the Edelbrock performer is a step down.....but talk is talk.

I'd do like they said, get in there, figure out what you have, check the condition of things and replace (upgrade) as needed.

That's what I've done. I didn't break the bank in the process either.

305
Comp Cams XE-262
Roller Tip Rockers
Weiand Action Plus Intake (got it CHEAP)
Edelbrock 600 cfm (rebuilt)
Jacob's Pro Street Ignition (used)
Open Element K&N Filter
Flowmaster 80 Series muffler
Custom instrument cluster from an 87 IROC

Soon to be Hooker Supercompetition shorties and 2 1/2 duals.

 

The way to approach modding a car (note I said car, not motor) is to identify its weakest link, and deal with it in a manner consistent with the rest of the car. It is not effective to simply throw a bunch of romantic-sounding, chrome, sexy-looking stuff at the top of the engine where everybody can see it when you open the hood.

This topic ("What do I do to my bone-stock LG4 car to make it less painfully slow?") has been hashed to death, and gets a post every week or 2.

The first weak point about that setup is the exhaust. Every single piece of it needs to go in the trash, from the heads to the street. It needs to be replaced with application-specific parts for some other car, NOT for the LG4. Any part that fits the stock LG4 exhasut will retain the bottleneck, and is therefore useless. Get the entire thing - headers, cat, & cat-back - for L69 or L98.

The next weak point in that setup is the cam. It is the tiniest, weeniest cam Chevrolet ever put in one of these motors. A good replacement is either the Comp XE262 if you have either a 5-speed or a 2400 RPM or higher converter, and you either have or intend to put in some 3.42 or 3.73 gears; or a XE256 if you intend to run 3.23 or lower number gears or a stock converter.

After that, you need gears. They put grocery cart gears in most of those, to help out with CAFE. AFAIK the best gears they ever got was 3.23, and most of them are worse than that. 3.42 or 3.73 make a world of difference, but only in conjunction with allowing the motor to breathe. The worst combination you could have would be a stock automatic, stock exhaust and cam, and 3.73 gears; this will pull hard up to about 5 mph, and have nothing above that, then the trans will take so long to shift that the RPMs will just hang at 4500 or so for a few seconds, then it will finally shift, then do it all over again in 2nd at about 12 mph, etc.

Then, they need head work. The heads that are on there totally suck in stock form but have reasonable potential when opened up. A good time to do that would be while you have the motor apart for the cam; pop the heads off at the same time and work them over with a die grinder, and have them fitted with positive seals to kill the puff of smoke at startup.

After all of those things are done that you can't see and nobody will oooh and aaaah over when you open your hood, you'll find that you now have a low-mid 14s car, and that the stock carb and intake and distributor are only now becoming the bottleneck. If you haven't done the other things mentioned above, all of that is a waste. You won't get anywhere near the full benefit of them, if any benefit at all, and you may even go backwards - like putting a Performer RPM intake on an otherwise stock LG4. That probably cost you a second right there, from the mismatch of the huge intake (kills low-end torque) to the rest of the motor (no top end whatsoever). Mismatches like that don't somehow "make up for" each other: each part costs you whatever sacrifice it's designed to make, and the other parts cost you their sacrifices, and in the end, you're on the losing end of both compromises without the benefits of either. Net net, you go slower.

Again, resist the temptation to just unbolt and re-bolt easy to get to stuff on top of the motor and replace it with the latest buzzword or the cheeeepest thing that calls itself "high performance". Spend your money on stuff that actually does something: for instance, avoid chrome water pumps, alternators and valve covers.... those types of playpretties just kill your budget and don't give you one millisecond in the 1320 or one single HP or ft-lb. Doing what you see others around you doing to their cars is the straightest path I know of to an expensive disappointment.

 

OBTW - I have a 83 L69, 3.73s, 5-speed. It has a Comp XR264HR-12 cam, 1.6 rockers, flat-top pistons, a set of old double-hump heads, Edlebrock TES, stock cat, stock L69 exhaust, stock carb, stock intake, stock distributor, stock air cleaner, stock cooling system except for a Stewart water pump, stock valve covers, stock every single piece of emissions everything including AIR, EGR, EFE, etc. to pass California emissions. Did I say "stock" enough times?

This car does 214 RW HP and 282 RW ft-lbs on the dyno, in this condition. That's considerably more crank HP, like about 35 more, than a stock 350 TPI, and equal to or better than alot of the modded 350 TPIs on this board. If I had a set of heads laying around when I built this with the flow of the double-humps and the right chamber size for a 305 to keep the compression up where it needs to be, it would probably have another 10-15 or so HP. Unfortunately though, I didn't, and this was just a scrape the stuff off the garage floor and slap it together kind of a deal. Rmember it has the same carb, intake & distributor that it came with. Those aren't where the power you are looking for is hiding.

 

:hail: RB83L69

's good to see someone pimp out the L69. Or any 305 for that matter....

 

We went over this in the carb board a few times. The 1406 and whatever the other "600 cfm" number flows more that listed. It does flow more like 650 CFM.

Like what RB83L69 was saying....
My personal results with the LG4 in my car were great the engine just couldent stay togather well enough with my lead foot and 80K.

This combo hauld @ss and dusted modded Rustangs like nothing. Action+ intake, 1460 Holley 600cfm, stock type pre cc distributor, melling MTC-1 cam with stock springs, added a 700R4 and 3.42 rear end. I would guess this combo would run low 14's easy even at this altitude but I'll never know. Note modded 350's found in street cars here usually run 14's-16's.

 

thanks for all the advice guys, looks like i've got a bit reserch to do before i break out the tools.. and where would i find these RPO codes?

 

under the console lid, if not their check inside the trunk storage comparment.