I know that this question probably has been beaten to death in this board. But after hours of searching and no resluts I have to ask. What is the max. HP/TQ/RPM that a 305 can punch out. All naturally aspirated. No power adders just motor. I'm not looking to do anything radical to mine, just wondering today. Thanks

J

 

I would like to know to, desktop dyno shows like 400 hp with just messin aorund on it, wh knows how accurate that is though...

 

I built my motor based off a Car Craft build up. They got 325 horse @ 5800 and 317 lb ft. @ 3800.

The differences with my motor are: 1/2 point more compression, I used a different intake, they used a victor jr. I used a performer rpm.

The reason why i went with the rpm was because a car with peak torque @ 3800 rpm is a waste of time with an auto on the street. They also went from stock to a perfromer rpm and got an increse of 20 hp. When they switched from that setup to a victor jr.....( minus the cam and heads) they got no increase whatsoever...but they lost about 6 lb ft and with the perfromer rpm intake, the peak torque was @ around 2900 I believe.

I also put 1.6 rockers on it for a bit more power.

I estimate my engine to be pushing 330hp/maybe 315-340 lb ft @ about 3000/3100 rpm.



I know you guys want e.t.'s but let's put it this way:

No $ for suspension right now.
1st gear= a major traction problem with 275's out back
I still have the original T.C.= If the car hooks it has no torque..if it launches, the tires are gravy....

The top end is incredible...and I know one thing for sure, it's faster than my 84' ( quite a bit ) and that runs low/mid 14's.

Look in sig for the mods on the 91'

Soon to come in the 91' = fully built 425 hp 355 c.i. motor.

 

Hot rod did a build up and got 400hp! I'll post the article.

 

Hot Rod article:

Deadly Lessons...
Hot Rod Magazine builds a 400hp 305

The process began with an ordinary 9.5:1 short-block (L69) as delivered from Chevrolet. To this package they added a hydraulic camshaft from Competition Cams' High Energy Magnum series and the attending valve springs and retainers. The cam is a CS292-H-10 that features 244° duration at .050" lift, 110° lobe centers, and .501" net lift on each valve. Crane Cams made up some .100" shorter pushrods to correct a slight rocker arm geometry problem; however, they probably wouldn't be necessary in every case. The cylinder heads are from RHS (Racing Head Service)and they sport Manley Pro Flo valves and a mild porting job.

Exhaust Ports
Intake Ports
Chambers
Pistons
Valves


Then they added an Edelbrock Victor,Jr. intake manifold and a modified 650-cfm Holley double-pumper carb. Hooker's 1¾" primary tubes headers were connected to a pair of Supreme Super C turbo mufflers. They already had an MSD-6A ignition amplifier in the car, and it was wired into one of Autotronic Controls' new MSD Extra Duty distributors. A 4" tall K&N air filter was attached to the carburetor. Everyone involved was surprised at the amount of power and the degree of driveability the package displayed.

Manifold
Headers
Exhaust System
Dyno Test Results


All of these modifications can be made to your stock 305 without ever removing it from your car, and they will provide similiar, but somewhat lesser, results when applied to the more common 8.6:1 LG4 305, 4-barrel combination. The compression ratio on this engine approached 10.6:1 when actually measured, and while we haven't physically checked an LG4 engine, we feel safe in saying that similiar modifications would yield a very driveable engine with better than 9.0:1 compression. This may seem like a bit too much cam for a small engine, and a Victor,Jr. intake manifold also seems out of line, but the engine is really responsive to the combination.

The best thing is that you can approach it in stages; each step adding a little more power without compromising the overall package. We suggest you work with the exhaust system first and then move on to the head work before installing the camshaft and manifold combination. But you can really do it any way you like and still get impressive results.

In early testing, the Z28 has already run 106 mph in the 13 second bracket, and we look forward to plenty more before we're finished. Now, of course, all these modifications are totally illegal if you drive your Camaro on the street, but they're the only things that make sense.

Miscellaneous

Con Rods
Oil Pump
Rear Main
Windage Tray
Parts List



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Dyno chart:

Engine Dyno Test

RPM Horsepower Torque BSFC
3500 210 314 .398
4000 243 319 .394
4500 270 320 .411
5000 316 331 .417
5500 361 344 .419
6000 376 335 .444
6500 378 305 .451
6850 386 296 .464
7200 402 287 .479

 

Here:

 

Are you planning on sticking with the TPI? If so, that's a severe limitation, especially the '86 version (MAF limits power because of the max flow it will sense). A SD TPI has more power potential, but you'll be spending some hefty bucks.

For what it's worth, DD2000 says mine puts 362 HP @ 6000 gross to the flywheel. Real-world, using altitude correction factors and 1/4 mile MPH conversion formulas, I'm putting 250 HP to the wheels (around 300 net at the flyweel). It would probably have better 1/4 mile numbers if the 2-3 shift worked at WOT, and I had gears (although that isn't supposed to affect MPH - we all know it does).

Mine is very well mannered. The 400 HP ones are not.

 

Your are talking about your Lg4 with world heads I assume.
Why are you only running 14.4?
I run that/faster with stock heads on my L69 and a little less than 300 horse.

edit: I would say it's your gears....but with all that jazz you should be faster.

Also...as far as the 400 horse motors being bad-mannered..they said the car was much more responsive than you would think...and that the Z-28 was running in the 13's @ 106.

 

http://www.wildgooseperformance.com/

Look down the page to the Monte Carlo

thats powered by a 305. with 305 heads and a Q-Jet carb.
( highly modified)

runs 10.99 in the quarter mile.

making over 500 hp

 

Never seen a wheel standing 305 before!!!

He must have some major power adding going on there.

 

Look at his SIG. He runs at Banidmer up in the mountains 900ft higher then the track I run at. No air means slower times and NHRA correction factors are sketchy at best considering air density changes constantly. If you can lay down 12's up here in a street car your damn quick, at sea level 12's arent jack. 15's and 16's are what most strong 350's run around here so for a 305 thats very good, oh course thats way too slow for me

 

I'm sure there is a lot more in there. The tranny not shifting 2-3 means I'm going through the traps at 6200 RPM (when I shift a 5500). Gears are great for the street but not for the track, same for the converter (a few hundred higher stall would help it get off the line better). Then I'd need traction. Plus, I've only taken it out there a couple of times to see what it would do, not to race it on a regular basis and tweak it out.

FWIW, my best time at Bandimere in the '57 corrected to 13.54 at sea level. In Topeka, it ran 13.44 for our one time trial at 7 a.m. when it was about 50 degrees, then ran low/mid-13.50's for the rest of the runs in the afternoon when the temp was closer to "normal".

 

Nope all motor Legal Super Stock car.

 

Looked at his sig= 14.56 corrected...I run a 14.41 uncorrected at 1,100 ft.

Look at my sig at my mods. Performer intake ( crap w/ egr blocked off), no traction, stock heads, and a fairly wimpy cam .420/.442 lift. Since I re-did my suspension I am faster because I am getting better traction. Although I lowered the car... I'm sure a set of relocation brackets will take care of that and I'll have even better launches.

 

FWIW, NHRA doesn't do altitude correction below 1200'.

But, you're right: I'm slow. You win.

 

I never said you were slow...but I do think your combo can be tuned to be stronger.

The correction factor for my elevation at 1,100 ft is ETx .9861.

I can't remember the mph but it's around MPH x 1.072 or something.

So I guess 14.42 x .9861 = 14.21

I don't really care. Mid- Low 14's are good enough for my combo right now.

edit: just re-did the entire suspension...but my clutch is gone...after I launch every powershift slips like a bastard. I ran it last night and with the clutch slipping like hell...the tires hooked but the powershifts were terrible...it still ran a 14.67 which corrected is a 14.5 or so.

 

i would like to see more of this car :hail:

 

I got that article too, from a very old issue of Hot Rod. Of course you forgot to mention that they blew the engine at the track (thats why the article was titled 'Deadly Lessons'.)

 

www.goingfaster.com has a lot of info on hot rodding the 305. It also has a links to where people have gotten up to 400 hp and with tbi.

 

OK How much HP can you push on a stock bottom end 305???

If you build it up but keep stock pistons, rods, crank???

Can you push it to 400 RWHP without destroying these items?

 

thats what u get when u spin a sh!tty cast crank to 7200

 

So what is the limit?

 

well mine took 230 horse before it blew..

id say 400 crank is about as far as u want you reliably
you could run 500 down the track a few times..
CHP? did an artice using an old junkyard 350 put a cam in it and ran it either 599 or 699 horse before they blew it up purging the nitrous at idle

(edit)..305 and 350 cranks and rods are the same..the piston is different and the weight is different..the 305 rotating assembly is actually closer in weight to a LT1 the a l98 is..

max rpm is 6034 before damaging harmonics occur

 

I thought that they were different?? Cause you have to modify the crank to get it to work in a 305 when making a 305 stroker. I dunno thats what I have heard.

Well I think I should back to my orginal question and clear something up....

I just wanted to know if you put all the best High Performance parts in that made the motor basiclly bullit proof, like the rotating assembly, heads, intakes, carbs etc. w/o using a supercharger or nitrous or even a turbo.

 

you have to use a 400 crank to get a 335 stroker..
so the block has to be machined for the longer stroke
the cranks and rods are the same, just differnt weight

 

sure u can,
you can use a forged crank and rods in a 305 that are made for a 350..u just have to balance them to lighter pistons

i think vader posted a while back. that the theoretical max hp from a 305 was like 1,400 or somthing, but thats like $47,867 bucks

 

http://www.goingfaster.com/spo/spo_t...y_central.html
This is the actual place you want to go to This site in general has a lot of content not all of it car related. This link will take you straight to his 3rd Gen info including how to get much power from an L03