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PostPosted: Mon Aug 24, 2009 11:32 am 
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TBI Slant 6

Joined: Thu Mar 08, 2007 12:05 pm
Posts: 108
Location: Shad Bay Nova Scotia
Car Model:
Just wondering if anyone had any input on machining away the spreadbore in an Offy intake? when my engine was dynoed on pump gas (street / strip build) my engine builder was trying a couple of carb spacers under the 500 Edlebrock, when it didn't pick up with the spread bore spacer he said if it didnt like that it probably doesn't like any. He said that if he cut out the center and rounded the sharp edges it should pick up 1 to 3 hp? Has anyone tried this with good or bad results, or could recommend any modifacations that may help?
Thanks
Derek

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70 Duster 238'', four speed ,3:91's, 500 Elde, Hookers
68 Dart 4 dr 225, completely original


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PostPosted: Sun Aug 30, 2009 11:56 am 
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TBI Slant 6

Joined: Sun May 02, 2004 12:53 pm
Posts: 157
Location: Ameliasburgh Ontario Canada
Car Model:
http://seniordragster.bravehost.com/mycar.html

(Very bottom of the page)

I turned mine sideways and ground the sharpe edges smooth. I also ported the intake at head side to just under gasket size. (this allows for good flow even in the event of a slight msmatch)
The difference turning the carb sideways makes is unbelievable although I doubt it WOT power would be different. Idle and low speed though is darn near perfect. This is also an Eddy carb although you may detect some of my handywork .
Don

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Don


Last edited by Dolmetsch on Sat Sep 05, 2009 4:40 am, edited 1 time in total.

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PostPosted: Sun Aug 30, 2009 9:11 pm 
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Supercharged
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Joined: Thu Jan 27, 2005 8:32 pm
Posts: 7834
Location: Portland-ish
Car Model: Fiat 500e
The Offy manifold does not accept a spread-bore carb. The 4-hole adapter on the manifold is to fit AFB types and Holleys to the old Rochester pattern on the manifold itself. I put a Holley 390 on my Offy manifold with the primaries towards the outside by using the adapter from my Clifford manifold. You can rework the Offy adapter so it can be turned 90°, but the Clifford adapter was already on hand.

BTW, Don, I like your road test write up!

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Joshua


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 Post subject:
PostPosted: Mon Aug 31, 2009 9:46 am 
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TBI Slant 6

Joined: Thu Mar 08, 2007 12:05 pm
Posts: 108
Location: Shad Bay Nova Scotia
Car Model:
Thanks for the imput guys, I was calling it a spreadbore ( four equal holes) because that is what I thought it was called. :oops: I thought the engine builder was wanting to remove the center and then radius the sharp edges to pick up power. Does anybody have the linkage issues resolved with a sideways mounted edlebrock in an A body ( 70 Duster) with a four speed.
Thanks again
Derek

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70 Duster 238'', four speed ,3:91's, 500 Elde, Hookers
68 Dart 4 dr 225, completely original


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 Post subject:
PostPosted: Tue Sep 01, 2009 6:11 am 
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Board Sponsor & SL6 Racer
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Joined: Sun Jul 30, 2006 8:36 pm
Posts: 2432
Location: East Arkansas
Car Model:
Derek
I have a 73 Duster with Offy and Eddy mounted side ways. It wasnt any real challenge to build a bracket for the cable type gas pedal. Since mine is a Race Only car i dont have to worry about a kickdown as mine is tied back.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered


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 Post subject:
PostPosted: Tue Sep 01, 2009 9:58 am 
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Guru
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Joined: Mon Oct 14, 2002 4:32 pm
Posts: 4880
Location: Working in Silicon Valley, USA
Car Model:
Seeing it's a 4-speed, you have it easy... no kickdown linkage to mess with.

Get a long throttle cable out of a 2.2 (transverse engine) Mopar and swap that in, then make a bracket and spring holder... Done.
DD


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 Post subject:
PostPosted: Wed Sep 02, 2009 5:38 am 
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TBI Slant 6

Joined: Thu Mar 08, 2007 12:05 pm
Posts: 108
Location: Shad Bay Nova Scotia
Car Model:
Thanks for the tips everyone...that dragster is top shelf cool!!
Derek

_________________
70 Duster 238'', four speed ,3:91's, 500 Elde, Hookers
68 Dart 4 dr 225, completely original


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