I need a few questions answered

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I need a few questions answered

Postby Whitey » Tue Mar 05, 2019 4:26 am

We are stepping up our grandsons car from an 8.9 engine to a 7.9 engine...it will be a heavy combination around 500 lbs as he is a growing boy at 13 he is nearly 6 feet tall and built like a man....we have a nick woods motor ...polar clutch....not sure about the clutch..it’s all black magic to me but it came with the motor we bought ( I am a bracket racer and can build a power glide in my sleep) ...secondary drive will probably need a spring change....what combination of sprockets would be good for this combo ....I have a 5.5 small chain setup in it now but want to step up to the big chain while we are changing over
Also I need to build an exhaust if I can’t get one here in Australia....I’ve been told that 2 foot is the ideal length starting at 1 3/4” and 2 or 3 steps
Also with the carby I have seen them run at an angle and also straight up and down....is there any advantage using ramps to level the carby.
Thanks in advance from a down under racer
Whitey
 
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Re: I need a few questions answered

Postby Kern Family Racing » Fri Mar 08, 2019 11:43 pm

Primary clutch-purple spring with 12-28-22 ramps
Secondary- red spring in 5th hole with a 42-46 degree helix
We run a 6.36 gear ratio 11/70 and we hit 8000 on the big end.
We were told 27” with 3 steps is ideal starting at 1 3/4 for exhaust
As far as the engine, the angel should be at 15 degrees. If not, get a set of angle plates. The only thing you need is the carb itself to sit level. The intake can be pointing down but the carb needs to be level. That should get you in the ball park.
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Re: I need a few questions answered

Postby Whitey » Sat Mar 09, 2019 5:57 am

Thanks..the clutch we got with the engine is junk so we are going to get a new clutch that suits the car and driver.....we have the motor in the chassis and the carby angle is perfect...was able to borrow an adjustable header and thought I can do better....at a lot less cost...the rear end ratio is about what I thought ..but after talking with some of the quick guys here they are running around 5.7 rear

Juniors are not the easiest bracket..
Whitey
 
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Re: I need a few questions answered

Postby jtracr » Mon Mar 11, 2019 7:36 pm

Just a little more... If your buying a new clutch make sure to go with an overdrive. In that heavy of a package you will probably need to be in the 6? Gear ratio to get a usable 60ft time. In that without an overdrive you could end up too many rpms at the big end.
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Re: I need a few questions answered

Postby Whitey » Tue Mar 12, 2019 5:06 am

jtracr wrote:Just a little more... If your buying a new clutch make sure to go with an overdrive. In that heavy of a package you will probably need to be in the 6? Gear ratio to get a usable 60ft time. In that without an overdrive you could end up too many rpms at the big end.

Thanks...we have decided that we’re going with an overdrive shockwave....we do have a racer here that imports stuff from an American supplier...saves all the trouble with dollar conversion and import taxes..we are going 12 tooth front and a 5.87 ratio..we will have to see how we go can always drop to an 11 front
Whitey
 
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Re: I need a few questions answered

Postby JustDoug » Tue Mar 12, 2019 6:14 pm

How much did the Shockwave OD set you back mate in AUD? Plus you can't beat them, simple, very little need to tune and repeatable. Zara Board went from Polar to OD S/W and was hitting et's with a couple of hundredths over and over
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