Power Estimate Help

gibygreen said:

I'm here today to get an opinion from some some more experienced users concerning my car.

I'm in the process of rebuilding my 289. After tearing it all down, we sent it to the machine shop to be cleaned and bored to .040 to remove some cylinder wear.

During this rebuild process we are going to.. Put in some Flat top pistons, port the heads, have some 1.94/1.60 valves put in, and put in a mild cam (http://www.summitracing.com/parts/sum-k30032).
After all this work, I'm wondering how much power it will make (flywheel) so, any ideas??

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Maybe 270 if you have headers and a low rise dual plane intake.

gibygreen said:

...using my DesktopDyno program I have It estimated it at about 346HP/336TQ
-Thanks, gibygreen

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Please put your desktop dyno away, it is way faster than your car will be!

Please tell us how much money you have?

what upgrades if any have been done to the bottom end?

how long ago were they done?

exactly what heads are you using?

what cc are the combustion chamber?

what intake?

what carb?

are they 0 decking the block?

what is your rear gear ratio?

can you change it?

do you want a drag car, freeway flier or inbetween?

do you want a mild, moderate or nasty idle?

that cam should be in a volkswagen.

Please tell us how much money you have? Hard to say, It's a project between me and my dad. (It's my first car so it's a work in progress)

what upgrades if any have been done to the bottom end? As far as we know It is stock

how long ago were they done? Engine was rebuilt about 10 years ago

exactly what heads are you using? stock A code 65 heads

what cc are the combustion chamber? 54.5 cc Is what the internet tells me

what intake? Edelbrock performer

what carb? Edelbrock 500cfm

are they 0 decking the block? I'm not sure, I'd need to ask my dad

what is your rear gear ratio? 3.00:1

can you change it? Possibly

do you want a drag car, freeway flier or inbetween? inbetween

do you want a mild, moderate or nasty idle? Moderate

Note: The cam was my dad's choice since it was very similar to the comp 268h and he'd had good luck with that cam in some of his past vehicles. Also, Yes It does have headers.

I hope this helps you give me a more accurate estimate

ok, xlnt job;

do you want to run 87 octane or 91 - 93 or are you using E85 corn gas?

here's what i might do if you are on a budget.

get the block decked so the pistons are around .005" below the deck surface.

buy hyper pistons. if you can't afford them just buy cast trw or badgers

get arp rod bolts installed.

buy the comp xe268h cam.

install 3.23 gears for inbetween.

install 3.43 gears for slightly quicker acceleration but you will not be able to do 75 mph on the freeway then.

if you do not change your gearing your car will NOT feel much faster. if you change your gearing only, it will feel like it has 50 more hp.

you really should install a 2000 rpm stall converter with an xe268h cam but you can get away without it. if you run the next size down you will not need it.

you should run around a 600 cfm carb. i would use an annular booster type. the summit ones are a good deal.

67cpe said:

ok, xlnt job;

do you want to run 87 octane or 91 - 93 or are you using E85 corn gas?

here's what i might do if you are on a budget.

get the block decked so the pistons are around .005" below the deck surface.

buy hyper pistons. if you can't afford them just buy cast trw or badgers

get arp rod bolts installed.

buy the comp xe268h cam.

install 3.23 gears for inbetween.

install 3.43 gears for slightly quicker acceleration but you will not be able to do 75 mph on the freeway then.

if you do not change your gearing your car will NOT feel much faster. if you change your gearing only, it will feel like it has 50 more hp.

you really should install a 2000 rpm stall converter with an xe268h cam but you can get away without it. if you run the next size down you will not need it.

you should run around a 600 cfm carb. i would use an annular booster type. the summit ones are a good deal.

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91 - 93 octane since we will be using flat tops.
And problem is with the cam, we already bought the 268H so we are kind of stuck with that. But if i were to do everything you said, then how much would i be able to expect out of it? Also, My dad only wants to spend as little as possible pretty much for the whole rebuild overall so he probably wouldn't want to spend over $1200

the cam you listed is NOT a comp 268h cam. it is a summit 261 cam. it only revs to 4500 rpm, your stock cam revs to 5,000.00.


if you do what i said plus port your heads you might have around 290.

67cpe said:

the cam you listed is NOT a comp 268h cam. it is a summit 261 cam. it only revs to 4500 rpm, your stock cam revs to 5,000.00.


if you do what i said plus port your heads you might have around 290.

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WHOOPS, Yeah you're right I didn't mean the 268h. I have the summit one

that cam will choke the motor completely.

Instinx said:

that cam will choke the motor completely.

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What makes you say that?

.

Anyone Else have a prediction to offer?

gibygreen said:

Anyone Else have a prediction to offer?

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does it matter?

can i change mine to 500?

67cpe said:

does it matter?

can i change mine to 500?

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Does it matter what other people say? Isn't that why you post stuff on forums? so multiple people can talk about it?
and I don't see why not if that's what you want to do

gibygreen said:

Does it matter what other people say? Isn't that why you post stuff on forums? so multiple people can talk about it?
and I don't see why not if that's what you want to do

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oh sure, its a reasonable question. i was just trying to make a joke, it just didn't come out right, sorry about that, lol. however, if someone says 350 hp and another says 400 hp etc, your car will obviously not run any different no matter what the guesses are.

you will hopefully get more replies by tomorrow, so be patient.

I hate to be the bearer of bad news, but you are a long way from 346hp. Let me try to use a bit of reason, not embarrassment:

There once was a little company called Ford. Ford worked with a chicken farmer named Shelby. Shelby worked with some college geeks who also raced cars. Ford used a similar cam to your 281 - the rest of the engine Ford made is similar to what you have. Ford made about 271hp. Shelby was a bit wilder than Ford and added a better manifold, carburetor, cam and exhaust than your engine and he made about 312hp. The college geeks were a bit wilder than Shelby and they added a bigger cam, more work on the heads, more compression and made about 350hp. Now the college geeks were revving the motor to 6,500 rpm and running a lot of timing, which they got away with due to the gas that was common back in the olden days.

Now with the above facts (or opinions depending on your knowledge base), do you still think you will make 346hp?

his cam is actually a 261 not a 281.

stock cam specs adv dur 266/244 lift 360/380

hi po cam is adv dur 310 lift 460

his cam is adv dur 261 lift 456

his cam is slightly "bigger" than a stock cam and far smaller than a hipo cam.

gibygreen said:

Anyone Else have a prediction to offer?

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well my 290 hp guess was with the set up i suggested. with your set u i would guess around 245-250.

a 68 shelby gt350 which has a 302 engine is rated at just 250 hp at 6000 rpm.


ENGINE BALANCE - This is something i would do no matter what other wise you might end up with an annoying vibration and if you do, the only way to fix it is to take the engine back apart and balance it.

3pt7v6xer said:

...Now with the above facts (or opinions depending on your knowledge base), do you still think you will make 346hp?

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I don't KNOW for sure what it will make, but.. I'm HOPING it makes 270-300. I don't think that's a very high goal to achieve considering the Hi-po 289 you mentioned before made 271 with minimal changes back in the 60's.

hi gibygreen just curious. why do you think 270 to 300 is not to high of a goal when the cam you are using is close to a stock 2 barrel cam and the cam mfg says the rpm range is only 800 to 4500 and the hi po cam is larger than yours and those engines ran around 6200 rpm in stock form. also your carb is not only 20 percent smaller than a hi po carb it is not an annular booster crb like the hi po is.

67cpe said:

hi gibygreen just curious. why do you think 270 to 300 is not to high of a goal when the cam you are using is close to a stock 2 barrel cam and the cam mfg says the rpm range is only 800 to 4500 and the hi po cam is larger than yours and those engines ran around 6200 rpm in stock form. also your carb is not only 20 percent smaller than a hi po carb it is not an annular booster crb like the hi po is.

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Because.. you said before the stock cam has an operation range up to 5,000 at 266/244 duration and the Cam I have has only at most a 5 degree difference with a lift of closer to the Hi-po Cam. So in other words, I know what the manufacture says but I believe it has a higher operation range than that. (so does my dad) Also, We will be running larger valves and ported heads along with headers. Whereas the Hi-Po just used stock A code heads and used cast iron manifolds. So I don't see how less than 1 HP per Cubic inch is a large goal.