Not enough power!!!

ppguzy · 06-21-2009

Ok guy's I'm new at this hole forums stuff so bare with me. I got a 302 bored 30 over. The only thing in this engine that is stock is the crank and pistons. i got a holley 600cfm, edelbrocks timing chain part #7820,Edelbrock Torker-Plus Cam and Lifter Kit, and edelbrocks air gap intake. I also have their E-street cylinder heads with summits roller rocker arms. with all this i dyno'd in only 220 hp and 245 of torque at the wheels. I was expecting way more!! Did i do something wrong?

PaulS · 06-22-2009

What do you have for exhaust and transmission?

ppguzy · 06-22-2009

I got tri-y's and the stock allison c-4. I heard something about not enough back pressure? could that be right?

Keving · 06-22-2009

What gear ratio are you running? What type pistons do you have? Flat or stock?

ppguzy · 06-22-2009

i got the stock ratio which i believe its 2.79 and my pistons are also stock. I'm gonna check my compression ratio.

cindys_sn95 · 06-22-2009

with your combo thats about right. probably needs a little more compression. to late for that now. get a little more gear, 3.55s-3.73s that will wake it up.

69moneypit · 06-22-2009

I feel your pain. I have the 302, bored 30 over, TRW forged pistons that are dished, stock iron 2bbl heads with mild porting, comp cam, edelbrock performer, 670 street avenger, headers, and C-4 auto. Dyno'ed at 218 rwhp. With your Edelbrock heads, i would have thought you'd make at least 40 more horses than you did. I changed out my 3:00 rear ration for a 3:55 posi. Its more spunky for sure but it still wont spin the tires from launch. I'm adding an AOD and AFR heads shortly.

PaulS · 06-23-2009

Allison didn't make the C4 - that is a Ford automatic.
If it is slipping at all it will affect your HP readings on the chassis dyno. That is why I prefer engine dynos.
Has it been rebuilt or had a shift kit installed? if not I would start by installing a TransGo shift reprogramming kit in the valve body. The part number depends on the year of your transmission.

ppguzy · 06-23-2009

so should i go with a more aggressive cam you guys think? thanks for all the info again guys. I'm deffinitly gonna rebuild my transmission. i still don't know what to really do. should i just take it out and go to a machine shop and tellm...Here figure it out!!! lol. or can i just do most of the stuff myself?

v8only · 06-23-2009

that's about right....those #'s are good. I assume that's 220 at the wheels, which is 260ish at the flywheel. Great #'s.

Remember, the vintage 289/302 cars only had 140-150 real world HP when tested by todays standards. You've essentially added another 100 hp to the factory amount just with h/c/i combo.

If you want serious hp, then you need to run a real unfriendly cam and a lot of compression.

My best advice is to yank the motor and start with a late 87+ 5.0 roller block. The 5.0 roller blocks with good aluminum heads and a good cam usually make 300-325 at the wheels. (assuming a stock bottom end with a cam and your typical mild alum heads) You "could" do the same with your vintage motor, but you're not going to like it's street manners when it's done.

Keving · 06-23-2009

You need gears man. Gears... 3.55 if you are going to run on the highway a lot. 3.70s if you are on the highway for short distances every now and then, 3.90 if you are never going to see the highway. That's what you need to wake it up.

Player · 06-23-2009

Quote:

Originally Posted by v8only

that's about right....those #'s are good. I assume that's 220 at the wheels, which is 260ish at the flywheel. Great #'s.

Remember, the vintage 289/302 cars only had 140-150 real world HP when tested by todays standards. You've essentially added another 100 hp to the factory amount just with h/c/i combo.

If you want serious hp, then you need to run a real unfriendly cam and a lot of compression.

My best advice is to yank the motor and start with a late 87+ 5.0 roller block. The 5.0 roller blocks with good aluminum heads and a good cam usually make 300-325 at the wheels. (assuming a stock bottom end with a cam and your typical mild alum heads) You "could" do the same with your vintage motor, but you're not going to like it's street manners when it's done.

Why would the stock engine have bad street manners as opposed to the newer 5.0 block?

v8only · 06-23-2009

the mustang 5.0 from 85-93 is putting out around 225 horse when rated by todays standards 1972+

When rating the 289 by the exact same standards, the 289 is putting out about 150hp.

You've got a 75 horse deficit to overcome just to get to the stock levels of the later 5.0 engines.

In a vintage flat tappet 289/302, the only way to make a lot of HP is going to be with a lot of compression and a wicked cam....this is the same combo that unfortunately makes for an unstreetable car. Of course, by the time you overcome the power deficit in the older motors, it's not a stock short block any longer.

If you're running a stock 289/302 flat tappet motor, you can never expect to make the same power levels of the later 5.0's. (STOCK shortblock for STOCK shortblock)

That's not to say that 289/302's can't be made to have some serious power. They CAN. I know of two vintage mustangs local to me with seriously wicked 289's. However, these are hardcore engines, built from the ground up. For a street machine, the 5.0 engines produce a lot more power without having to touch the short block except to swap in a mild cam.

it's just a matter of technology that's surpassed the early years.

The same thing has happened to the late model 5.0 block. While the 5.0 engines make 225-300 horse at the flywheel stock (the explorer motors will make about 300 flywheel horse), compare that to the modern gm and chrysler motors....the gm ls engines are making 400-550 N/A out of just 50 cubes more, and the chrysler hemi's put out 400 hp on average.

It's difficult to compare vintage muscle/engines with today's vehicles. This is why I suggested to the original poster that he be happy with his end results, and instead spend more time fine tuning what he has, rather than compare the power levels to newer engines.

alpha male 67 · 06-23-2009

"Why would the stock engine have bad street manners as opposed to the newer 5.0 block?"

i'm sure he means that to get those kind of numbers on a older 302 with the flat cam the 350 horses are much harder to reach
i was in his same shoes and i ended up pulling my 302 and dropping in a 91 5.0 just so i could have the roller cam to make those nice HP numbers , it was the best thing i did
but it is a double edge sword , you have to rebuild your tranny
to handle the hp or get a new one, i went with a TCI "streetfighter" and your 8" rear end with those 2.70 have to go! i went with 3.55 and track-loc and i cant imagine going back ,my 8" is holding up fine so far -- its alot of work and money , one thing i have learned is that HP is not cheap

65redcoupe · 06-24-2009

ya early cars without huge big blocks just cant put up the power our cars do today just the difference in frictional horsepower in the last 40 years is absoloutely astonishing!.....cars today are so much more efficient in every way and back then they just didnt have the same technology like all the computers and such.....the really fast cars back in the day were the big block 428s and 429s....now today we see cars easily drivable on the road with over 500 horsepower without 5 mpg and a cloud of exhaust behind you....we now see 283s with stock 310 horsepower!!!...its astonishing when you look at it