Got a friend who has an 86 Z with the standard LG4 305. Yeah, I know not the best by far. For someone with an eye towards my first Third Gen, how much does a 350 in good, used condition typically run?

Buddy of mine doesn't think its feasble to switch from the 305 to the 350 as of it, because he'd have to take the car somewhere to get it professional switched as he's no clue about engine swaps.

At the moment he's looking to drop 700-800 dollars into his dependable, solid (though somewhat underpowered) 305 to elk out some more HP

 

There's not really a "usual" cost; every one is different. After all, they come out of wrecked cars; have different miles on them, and so forth.

He's not going to do an engine swap for $700, if he has to include buying a ready-to-run engine. That's pretty much a pipe dream.

Meanwhile, there are ALOT of things that make LG4 CARS slow, besides the ENGINE. Everybody (especially people with little to no experience) wants to think that if the CAR is slow, it must be because the ENGINE is inadequate. That just isn't so.

The best way to improve a car, is to find the ONE THING, whatever it might be, that's acting as the limit to its performance; and upgrade it in a sensible, rational way, that's compatible with the rest of the CAR. That ONE THING might or might not be under the hood, and in fact, usually isn't.

In the case of the LG4, the FIRST THING that needs to go, is the exhaust. Every single piece, starting at the heads and working toward the back bumper. It should be replaced with a chassis-specific (NOT "universal") set of headers; a high flow cat such as a Catco; and the cat-back of your choice. All of these parts should be specifically for 82-92 Camaro/Firebird V8, but not for LG4. ANY piece that fits the existing LG4 exhaust will PRESERVE THE BOTTLENECk, which is of course exactly what you DON'T want to do. I'd recomend getting the whole shooting match for about a 89 TPI 350. Don't futz around with "true duals", muffler shops, "custom" systems, etc. There are many well-engineered systems on the market, from Flowmaster, Edelbrock, Hooker, Dynomax, Borla, etc. etc. etc. Get one of those that suits your taste. For headers, look at Edelbrock and Hooker. SLP used to make them but has discontinued them; they are VERY good however, and still show up used from time to time, and are worth investigating. Also, Dyno Don on this board, has started making some, and his may be worth taking a look at. A complete exhaust sysem like that will run about $700. Keep in mind, that a 350 needs the same thing, EXCEPT WORSE; putting a 350 in the car but keeping that coffee-stirrer sized exhaust will prevent the 350 from really making any difference at all.

The next thing that slows the car down is the rear gears. If it's an auto car, it probably has 2.73s. A set of 3.23 or 3.42 will totally revolutionize the car's acceleration; 3.73s also, but those are borderline too much. To have a shop do that will be around $600. Again, a 350 will benefit just as much, if not more, from that, as the LG4; and they will prevent a 350 from doing much good.

Start with exhaust, and see where that takes it. It is the foundation for everything else.

Other things he can do that will make the car BETTER, if not faster, include subframe connectors; a "wonder bar"; new sway bar bushings and end links, which the Energy Suspension ones hanging in the "performance" aisle at AutoZone and such places are PERFECT for; changing the rear end fluid and putting in synthetic (improves gas mileage a bit, as well as reducing power loss in the drive train); and better tires.

 

I'd add air cleaner to that list. There is a tech article linked from the thirdgen.org homepage about converting a stock single snorkel air cleaner to dual. That also makes a big difference for the 305, and even more with a 350.

But, I totally agree that the first $700 should go to exhaust. Unless you do that, nothing else you do will matter. It's exactly what is said in the thread on the FAQ forum about the differences between 305's and what to do for performance improvements.

 

Thanks for all the info.

(No, he isn't trying to get an engine swap for 700 dollars. lol, thats all he has to work with on his current set-up)

I never really realized exhaust made that big of a difference. Of course, I've only worked with Jeeps during my younger days and we never really tried to max out the HP...

How much additional HP would a good exhaust system like you mentioned create on a LG4?

Also, when you get new rear-end gears you need to get a matching speedo, correct?

 

I agree with most of that...revamp the exhaust and get some gears in that car. I went from 2.73 to 3.23 and that was a huge difference. It was too much for the 200 tranny, though.

I'd throw in this tidbit: Swap the anchor OEM intake for a new intake manifold...be careful of emission laws, though. I went with the performer, and that made a profound difference--as much as the gears. Alabama is relaxed...I ditched the computer years ago.

I have a 305, but have been preparing for some more serious horsepower. I've tried to make sure that each upgrade put me in that direction if possible. The 3.23 was the most I could stand with the 305/200 combo. The suspension has been beefed up as they mentioned above. Adding the sub-frame connectors helped a lot. I found a quick-ratio steering box and added it, and Eibach & I lowered the car (many say lower is the wrong direction) and I refurbished the front end with MOOG's best. If you lower the car, make sure you use the relocation brackets on the rear. If not, those 3.23 gears will have you peeling out in shifts. I don't want to burnout (at least...prematurely)...I want as much traction as possible to keep the advance on the poor guy melting his tires behind me.

 

By itself, not a whole lot, maybe 5-15%. Noticeable, for sure. The main thing is it also allows other HP mods to work.

No, you need to match the speedometer drive gears. Located in the transmission tailshaft. There is a calculator on tciauto.com (there are others, I like theirs the best). With a big gear change, you'll have to change both the drive gear on the output shaft, and the driven gear that the speedometer cable attaches to.