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Top HP for 283

justchilln1424's Avatar
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October 25th, 2009, 6:47 PM   #1  
Top HP for 283

Has anyone ever tryed to beef up a 283 v8 sb before and if so whats to most hp you can get out of it wt all the top proformence parts, (Hyd. lifts, Pistons, cam, rockers, oil pump, etc, etc) but just straight engine no supercharger or turbo? Cause im thinking of doing it to mine.

MixedBag75's Avatar
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November 18th, 2009, 10:26 PM   #2  
I have a 283 that I just had built, I just got it from the shop yesterday. I had it bored 0.030, put a cam in it, an Edlebrock Performer intake manifold (#2101), and have a 500cfm Edlebrock Performer carb that is going to ride on top. It's going to be a while before it gets fired but here's a few questions about my build, that I have.

According to my research using the driver side head casting number and the block cast number it is a 1966 model 283. I have been told that I have the Power Pack heads. Can someone explain the significance of these heads to me?

Now my real question, I have the cam specs and would like to know what I can expect out of this enige once running.

Here are the numbers at 0.050 duration:
intake - 204, exhaust - 214
The lobe centers are:
intake - 107, exhaust - 117

SAE duration:
Intake - 278, exhaust - 288
Valve lift:
Intake - 421, exhaust - 444
Cam lift:
Intake - 281, exhaust - 296

This engine is going in a 4x4 with 4.88 gears and planned 37"-38" tires. I left the cam selection up to the builder but I am looking for low end torque and not sure what to expect here. Any help or incite will be appreciated.

Sorry for such a long first post.

mudmaniac's Avatar
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November 20th, 2009, 4:25 AM   #3  
MB75, I think you will need a little more carb than what you have.

desrtrat's Avatar
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Daggett CA

November 20th, 2009, 4:25 PM   #4  
if i remember..the power pack heads were from the 55-57 265, and 283 motors. they were used until 67. a med. performance head with 1.92 intake valves, small ports. if you are going to use these heads make sure the valve seats have been replaced with harden seats. those heads were meant to be used with leaded gas.
the next big question is what compression ratio are you going to be running? when the 283/327 were making real good power, factory compression ratio was 11.1 + with 100 octane pump gas. back in the day we could get over 525 hp out of 327s but we were running 13.1 pistons. hogged out fuelie heads and 120 octane gas..i would sell/keep the 283 and go 350/383/400

good luck

rubrhammer's Avatar
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November 20th, 2009, 8:28 PM   #5  
With the duration of that cam I would not expect a lot of low end TQ. If you know much about your heads, go to the Comp Cams web site and download CAMQuest6.
With that free program you can get very close to what you can expect from your set up.
Are your heads 461 castins? You can find what your heads are from here:

MrChevy's Avatar
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December 29th, 2009, 8:27 AM   #6  
Numbers, give me NUMBERS!

Heads and what valve sizes came in them and other small items of interest.

PowerPak heads were in use until 1967 on the 283, the last year of the 283. The only difference between those and the "regular" heads on the 283 was they had a little more spring rate (stronger spring) and a damper in them.
ALL of those heads had 1.72" intake valves and 1.5" exhaust valves.
They never made a bigger head until the 327 came out in 1962. Then they made the "fuelie" heads with 1.94" intake valves. They had 461 and 461x castings and had the double camel hump on the ends for the HP heads then, the 250HP 327 still used the PowePak heads that were on the HP 283's. The 2.02" intake valve didn't come out until 1964. Thus my 1963 Fuel Injected Corvette had 1.94" intake valves which I switched out for 2.02 angle plug heads.
With the cam shown, from personal experience, a 283 with that cam should be able to rev (with the correct valve springs) 5,500 easily, Pretty much a little bit up from a stock replacement cam and it is a low end torque cam, good from idle to 5,500 Edelbrock says. It is the cam that comes in the Performer Plus kit where you choose cam, manifold and carb.

rubrhammer is correct, click on that Comp Cams link he gave you and find the correct cam for more torque. Downloading their software, I must say, they sure have their site throttled down. The highest download speed I received was 82KB/sec. 1,000KB is MUCH better, the 20MB download would take about 20 seconds instead of close to 6 minutes.

A 650 or 700 CFM carb would be better suited so it didn't starve for fuel when you had it in low range and wide open throttle.

Some headers with 1 tubes running into some Flowmasters would probably help a little on the torque too.

About your gears/tires. If your rig came with freeway gears in it, say 3.73's and 29" tall tires, you wouldn't even have to change your speedometer gear because 4.88's with 38" tall tires is the SAME ratio.
That means:
If you are driving down the highway with the stock 3.73 gears and 29" tall tires and you are going 60MPH, your tach will be reading 2,594RPM.
If you change your rearend to 4.88's and put 38" tall tires on it, then at 60MPH your engine will be turning 2,590RPM. Really, really close to the same, don't have to worry about your speedometer being off at all.

The formula I made for that is: RearRatio/TireDiameter=NewRearRatio/NewTireDiameter.

Thus, doing it on a calculator: 3.73/29=.1286 and 4.88/38=.1284 Real close.

You can use the numbers like so: 3.73/29=.1286 and then take that number x your new tire diameter and it will tell you the REAREND RATIO you need.

3.73/29=.1286x38=4.88 Simple little formula, but handy to have.
OR, if you have new gears and wonder what tire they would match, use the numbers this way:
3.73/29=.1286 and then put in 4.88/.1286 and it = 37.95 tire size.

For the parts you have listed, using cast iron exhaust manifolds you should be about 265HP and with the small tube headers and exhaust about 295HP.

On the 327 and 525HP. When I had my speed shop the '70's, we would change the oil and stuff in a Jeep that had a 601HP 283 in it. Had a two barrel carb on it. No, no, wait... oh, the Jeep with the 283 had a 671 blower on it running on alcohol. Girdle on the mains and all the good stuff to hold the HP.

But, getting back to the 525HP. That would pull a 3,000LB car (IF everything was set up correctly) to a 10.40 sec ET @ 131MPH. Do you have some numbers for us desrtrat? What body? How gutted out was it. What was it's weight? Tire size? Rear ratio? I love looking at numbers like that.

Those formulas are HP needed for MPH: HP=(MPH/234)^3 x Weight
HP needed for ET: Weight=(ET/5.825)^3 x HP

They are both pretty close IF the car is set up correctly. Correct gear ratios and tires etc.

jretzky's Avatar
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April 22nd, 2014, 11:22 PM   #7  
Top HP for 283

Back in high school I had a 1966 Chevy Impala with a 283.
I went to a trade school in Chicago for auto mechanics.
That engine had 9.25 : 1 and most 350 CID had 8.5:1 compression ratio.
Get what you need from Eldabrock- cam, intake, and 650 carb.
Do a 3 cut on the valves for better flow.
Get the headers and mufflers to match.
Get rid of the 4: 88 rear end and get an 4:10 posi- traction.
I basically did the same thing with my 1967 Dodge D200
With an 318 CID . But it has a double roller timing chain.
I have a heavy truck ( now it's a 4x4) and it has a 4 speed manual trans.
It screams and has great low end tork.


jretzky's Avatar
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April 22nd, 2014, 11:31 PM   #8  
Oh!~ Don't for get the electronic ignition, get rid of the points.
Get an high out put coil, some heavier wires to handle the hotter spark.
Don't forget the spark plugs either for hotter spark it runs a wider gap.
You'll be surprised what you can get out of that 283.

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