ll-84camaro-ll

ok guys i need an engine that has a good bit of horsepower and is a good platform block to build up because right now my 305 is reaching the end of its days (204k miles) also i dont have alot of cash right now so the cheapest engine with horsepower and gas milage is what im looking for if you guys can help me out in my search for an engine i would greatly appriciate it

Air_Adam

Start with a 350.

ll-84camaro-ll

i was thinking abouta 350 but that wouldnt help my gas milage situation my car is a daily driver and cant afford to decrease my gas milage any more than what its at(lg4 305)

Stekman

A 350 can be made as mild or as wild as you want. I doubt you will see too much of a difference.

Any time you increase power output (natural aspiration, conventional methods)), you decrease economy. It's a rule. Breaking that rule is breaking how the engine works. So, which do you want? Economy or power?

ShiftyCapone

iTrader: (7)

Correct. However, with todays multi port set-ups you can have great economy during part throttle and cruising situations with the right gearing. Plenty of LT1 and LS1 cars running 12's and 13's all the while netting 25 to 30 mpg going down the highway.

StreetRCR

Those cars generally have six speeds. If you want economy AND power you will have to look into a power adder such as Nitrous or a blower. The economy will then depend on you foot to floor ratio.

Air_Adam

Not true. Proper parts selection and good tuning can make lots of power AND good gas mileage.

There are lots of guys on this board with yerbasic 4bbl 350 making 300hp or better and at the same time getting 20+mpg.

five7kid

iTrader: (14)

Looks like part of it has already been decided https://www.thirdgen.org/techbb2/sho...13#post2014213 .

A Crane 2040 Compucam or Comp equivalent would yield good power and maintain good manners and economy. Take your 305 heads, have the intake seats opened up for 1.94" valves, clean up the bowls and ports ( http://www.sa-motorsports.com/diyport.shtm ), use pistons with a slight dish, and follow the intake and exhaust recommendations in the other post. Oh, you've got to ditch that single snorkel air cleaner, either with a factory dual or one you fabricate (see tech articles on the TGO home page). You'll have a setup with good power, good daily driver manners, and decent mileage. I've done all of the above except 2050 Compucam, ZZ4 intake (it was cheap, bud's take-off), ported World 305 heads, and it's still a 305. I drive it to work daily year round, average about 16-17 MPG commuting (would be better if I could resist putting my foot in it for a complete tank - rare), and I record & track my mileage each fill-up. I don't do much highway driving, but have gotten 21 MPG on the rare occasions when most of the tank was highway. A 350 would do just as well as long as you don't get in it all the time.

StreetRCR

True BUT 300 hp isn't a lot of power. 300 horse is less than stock on most vehicles. When I was saying a lot of power, I was thinking 450 hp and up. It's all relative when you are talking about cars with hp #'s like ours came with from the factory.

I street drive a 500+ horse motor and it would be hard to tune for economy.

DENN_SHAH

iTrader: (1)

ll-84camaro-ll, on my monte carlo i went from the stock 305 4 barrel carb motor to a flat topped .030 over 350 with a mild cam & a elbrock dual plane intake & went from 16 to 17 miles a gallon in town, plus it towed my bike trailer much better. i used the carb, ECM, & full exhaust from the 305. a bigger engine doesn't necessarily mean a drop in mileage, as long as you keep your foot out of it.
with the TPI 350, now im getting around 20-21 in town.

Rembrandt

not driveability with respect to HP...

drivability with respect to HP per liter. the more extreme the build, the more horsepower you want, the more you want torque at higher revs, the more compromise with the rest of the RPM range.

You could have a mild build 5 liter making 300 or an equivalent mild build 10 liter making 600.

But I figure since you care about gas mileage then you don't want at 610 cid engine.

when you say drivability do you mean more like "something not impractical for daily driving" or "has a broad, usable power band."??
Both I guess.

A 350 is fine. for power and gas mileage an LS1 would be the ideal lower-cost prebuilt package but it sounds like that is out as well.

Kingtal0n

In any naturally aspirated situation your economy to power ratio is going to be drastically effected by your actual power output VS engine displacement. In other words, a small N/A motor will not make big power numbers without a huge sacrifice to economy. A large V8 motor N/A can have better N/A numbers than a smaller motor and still maintain economy. Until you step up the power : engine displacement ratio. then you have a large motor making lots of power but again, economy is drastically effected.
Example: 2.4 liter motor: 150 horsepower @ 6500RPM. Economy is maintained in this stock example of the KA24DE motor installed to Nissan vehicles.
Same 2.4 Motor, 220 Horsepower @ 6900RPM: You have raised the VE of the motor drastically at higher RPMS by Head/cam/Intake modifications, the result is a motor that makes plenty more power but the sacrifice is low-end torque (streetability) and economy (as in how fast can you go from gas station to gas station)

Example2: 5.7 Liter motor LS-1: 300 Horsepower @ 5800RPM. Economy maintained, streetability maintained, economy maintained.
Same 5.7L motor LS-1: 470 Horsepower @ 6400 RPM. You have modified the intake/heads/cam to provide a higher VE (volmetric Efficiency) at a much higher RPM. the result is a loss in low-end torque (read: streetability) and fuel economy.

Some people can live with the loss, some can't.

However, there is an alternate solution. that same 150 Horsepower 2.4 Liter motor can be left alone, stock, with its full economy and streetability intact, and with the addition of nitrous, supercharger, or turbocharger it can become a 300+ horsepower motor and still net the same factory programmed fuel economy.
As for the 5.7 Liter (350) motor, an addition of super/turbo charger can net you even 500,600, and with heavy mods, 900-1200 Horsepower with near-factory fuel economy.

Keep in mind, because of friction loss and reciprocating mass the smaller motors will typically enjoy a higher RPM cutoff and less low end torque than your typical V8. the car must be geared shorter and lower to maintain a higher RPM to keep the drivability intact. Also keep in mind that the smaller motors, are typically installed in lighter vehicles.
To give you an idea of how big a difference that makes, my 2600Lb. 240SX with 250 Horsepower can beat your 3400Lb. camaro with 380Horsepower. Gearing and weight and powerband play a huge role in how the vehicle moves down the road and if it feels "right".

TexasLT1

I've got a 400 horse LT1 with a 5 speed pulling almost 30 mpg on the highway at 65-70 mph. 85 mph = 23-25 mpg with 3.42 gears

Kingtal0n

And now just imagine bumping it up to 550RWHP, N/A and keeping those economy figures.

but with the addition of a supercharger (a a bit less compression) you could net that 550RWHP, and keep that 28MPG highway. I beleive this is the point that was being made, originally right?

paul_huryk

Mileage has to do with efficiency, but don't forget a lot of tricks to make cars faster also decreases economy. For example you will lose a few MPG going from 3.23 to 3.73 gears in 99% of cars (OD or not). You will lose a few MPG if you run a 2800rpm TQ converter vs a 1600rpm stock one. Adding weight (such as stereo equipment) will decrease your mileage also. But you can take a stock car and add power into it by increasing efficiency and still get better mileage - headers and low restriction exhaust (LG4 is the perfect example); underdrive pulleys; lose some weight in the car (100+lbs); use low friction lubrication in motor, trans, and rear; inflate tires to 34psi instead of 32psi..... the list can go on and on.

89FormulaLS2

"MOST" vehicles come from the factory with a LOT less than 300 horsepower, even @ FLYWHEEL horsepower. There are NO 3rd Gen F-bodies that came with that kind of power, you've got to get into 4th gen cars (LT1, LS1) for that. Even now, in 2004, there are not a lot of factory cars (or SUVs or Sport trucks) that are coming off the lots with 300+ hp. Gotta have a V8, and the vast majority of cars are using 4 bangers and V6's. Not counting trucks, please list the # of cars other than the 'Vette and the GTO that are going to come off the line in 2005 with STOCK 300+ RWHP!!

89FormulaLS2

Actually, there are plenty of guys with LS1 engines running that kind of power N/A that are still getting high 20's for mileage with 5 or 6 speed manual transmissions. Pedal-to-floor ratio has to do with everything.

Remember, we are talking PEAK horsepower here, and at those kinds of numbers (500+) you are running at 5000-7000 rpm with wide open throttle, attaining your peak hp for a brief period.

These same engines can be running around town at 1500-2000 rpms with just an extremely light touch on the throttle, using a FRACTION of their potential power, and get great gas mileage all day long. Even city driving they can be making mid 20's. It's only when you push that pedal to the floor that you shove all your mileage out your exhaust.......................

89FormulaLS2

My opinion:

You probably want to go with an LT1 and a 6 speed. The increased gas mileage with the T56 will pay for the cost of the trans many times over, especially if you do a lot of trips. The LT1 can be had for a pretty reasonable price, parts are plenty and cheap, and there are plenty of guys making 400-500 hp with that engine that still have excellent street manners.

If you can go the extra mile on cost right now (especially if your state is easy on emissions requirements) then the long term best platform for BOTH economy and power is going to be the LS1. 450+ rear-wheel hp N/A is EASILY obtainable with head/cam/exhaust package, and with power-adders there are 800+ rwhp cars driving around that run as good as stock, STILL getting great gas mileage all day long.

Kingtal0n

if you are running a serious head/cam combo to make 550RWHP in N/A format from a 347~CID Motor, it doesnt matter how many gears or how high your gearing is, your low-rpm fuel economy is going to suck absolute $#!T compared to stock, Ls-1 or no Ls-1, simply by virtue of overlap and low port velocity generated by the larger runners in the heads. Fuel distribution and sequential EFI go a LONG way for fuel economy in those situations, but the bottom line is in such a radical (and yes an Ls-1 running 550RWHP N/A is radical) format the motors low-end is ALWAYS going to suffer (thus most people in those instances run 4.11's and rely on the .5:1 OD to make up for it..) no matter what.

I Promise you, there is not an Ls-1 guy out there making 550RWHP to the wheels on the stock internals N/A and getting near stock fuel economy around town. it just doesnt happen. Highway is another story, there are alot of other factors involved with a happy highway motor. Typically port velocities are way up because cruise RPM is decent and vacuum is high. overlap still nails you but it isnt as bad because cylinder filling is down. but around town? those guys are lucky to get 11MPG city, if that. Not saying impossible, just extremelly unlikelly.

The main idea of my post was to point out something that everyone should know, if they dont already. In your typical situation, small block chevy, N/A motor, 300-400CID, in your typical 3400-3800Lb. Camaro F-body (any gen), for most 95% of us out there, as peak horsepower goes up beyond 6000RPM and 400RWHP in this typical situation because of head/cam/intake/exhaust modification, your drivability/fuel economy will go DOWN. the post I replied to was <b>I've got a 400 horse LT1 with a 5 speed pulling almost 30 mpg on the highway at 65-70 mph. 85 mph = 23-25 mpg with 3.42 gears</b> I Was pointing out the fact that if he threw some AFR 220CC heads and a Solid roller 244/254 @ .050 cam and ported his intake to death, spun the motor to 7,200 RPM and made this 550RWHP, his drivability and fuel economy WOULD suffer drastically from before. In the same instance, he could leave his stock heads/cam/intake and KEEP his fuel economy numbers, add on a procharger or the like and nail the 550RWHP bracket way before 7,200 RPMS and maintain drivability. this is your typical situation, and its why we are seeing more and more power-adder cars out there making these numbers without the lopey idles that everyone seems to like.

My car is a near-stock sounding camaro, great fuel economy and drivability, even has factory 2.73 gearing. but under the hood? Http://www.geocities.com/kingtaling/turbo