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Discussion Starter #1
Ok I have a new used engine purchased from qualityautoparts.com. I don't have the old engine from my 1974 chevy nova. It got scrapped before I could remove the flex plate or anything else for that matter. So my new engine arrived and the flexplate has a bolt pattern of 10 and 7/16" and 11.5". The converter on my car has a bolt pattern of 10". I have heard that they make a flex plate with bolt patterns of 9 3/8" and 10" but I can't fine one yet. Can anyone suggest anything.... There are some photos on my photo album.
 

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I looked up B&M, TCI and Summit brand flexplate specs/dimensions most of the ones I found have the same dual gm bolt pattern of 10.75" and 11.5". Summit racing has a 153 tooth 9.75"/10.75" converter bolt pattern. (link below)

http://www.summitracing.com/parts/nal-471529/overview/

But I could not find any brand with a 10" bolt pattern. Worst case you may have to bite the bullet and buy a new torque converter if you can not find one with the appropriate pattern.


Good Luck on it:yes:
 

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Take the old flex plate and convertor off, place the convertor on top of the flex plate with the centers aligned, mark, punch and drill new holes in the flex plate, clean up the holes with a file and re-install. If you are worried about too many holes you can always weld up the existing holes that are not being used just remember to weld across from each other and let things cool down between welds to avoid warp-age.
 

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Take the old flex plate and convertor off, place the convertor on top of the flex plate with the centers aligned, mark, punch and drill new holes in the flex plate, clean up the holes with a file and re-install. If you are worried about too many holes you can always weld up the existing holes that are not being used just remember to weld across from each other and let things cool down between welds to avoid warp-age.
In theory this will work but, if holes arent drill dead on one would have problems with alignment which would wipe out the transmission front pump, seal and also cause severe balance issues. I would get the correct flex plate and or torque convertor and be done with it.
 

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In theory this will work but, if holes arent drill dead on one would have problems with alignment which would wipe out the transmission front pump, seal and also cause severe balance issues. I would get the correct flex plate and or torque convertor and be done with it.

^^^X2 I agree. Why risk damaging the trany just to save a few bucks.
 

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In theory this will work but, if holes arent drill dead on one would have problems with alignment which would wipe out the transmission front pump, seal and also cause severe balance issues. I would get the correct flex plate and or torque convertor and be done with it.
yes if he's off just alittle bit...its gonna be out of balance and tear up the tranny.......I wouldn't do that not worth it:no:
 

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Not to mention that should all be balanced, I'd be afraid of throwing the balance way off.

Just my :2cents:

Mark
 

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Excuse me if I'm wrong, but redrilling the flex plate wouldn't do anything to the engine balance. The plate would still mount on the crank in the same location. I'd get it as close to equal as far as offset from original holes though. If you take your time layin out the holes it shouldn't give you any problems at all. The converter centers off the hub in the crank. People do this all the time.
 

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Excuse me if I'm wrong, but redrilling the flex plate wouldn't do anything to the engine balance. The plate would still mount on the crank in the same location. I'd get it as close to equal as far as offset from original holes though. If you take your time layin out the holes it shouldn't give you any problems at all. The converter centers off the hub in the crank. People do this all the time.
True, it centers off the crank. I would not weld up any holes though.:yes:
 

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Discussion Starter #12
Wow thank you everyone bigtime. I have done some milling and precision work but I have a friend down the street who runs a grinding / machine shop. She's this 54 year old Marine who is smarter and quirkier than ever met. I'm sure she can handle the job of making new perfect and perfectly balanced holes. Do I need to remove the tranny to take off the converter? I want to measure the bolt pattern on the converter in a more controlled manner because if the 9.75 patterned flexplate works I will probably just purchase it.
 

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Discussion Starter #13
So same care different issue. I can't find any kind of sending unit for the gas tank. Or even a cap of any kind. I must need to learn to search the parts stores better or something. I'm assuming there is a wire that runs from it to the gas gauge. I can find plenty for 73 novas and earler but nothing for a 74.
 

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Discussion Starter #14 (Edited)
lets 86 the question about taking the converter off. (slid right off like the man said). Lost a tablespoon of trans fluid but I'm gonna change all that later. I carefully measured the diameter of the bolt holes and it's exactly 9.75" Thank you for finding that TorqueMonster. Ordering now. I assume Summit Racing is a good place to order from. There's a sticker for them already on the radiator shroud.
 

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Wow thank you everyone bigtime. I have done some milling and precision work but I have a friend down the street who runs a grinding / machine shop. She's this 54 year old Marine who is smarter and quirkier than ever met. I'm sure she can handle the job of making new perfect and perfectly balanced holes. Do I need to remove the tranny to take off the converter? I want to measure the bolt pattern on the converter in a more controlled manner because if the 9.75 patterned flexplate works I will probably just purchase it.
Really...... ?:rolleyes:
 

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Easy there Balljoint... (just realized how cool that name would be for a Transformer LOL) He is new.. just starting out... AND he figured it out.. good work Johnny.. we have all asked a question and thought rt after... damn how stupid did that sound..... :yes: have a great day all..
 

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Discussion Starter #18 (Edited)
We all have to start somewhere. So if I might offer some more entertainment to Balljoint... I have a "retarded I'm sure" question about 2 barrel vs. 4 barrel. I kept the Holley 4779-9 off the old engine. I'd like to change the intake manifold on the new engine to fit the Holley. Is this a sound idea?
 

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We all have to start somewhere. So if I might offer some more entertainment to Balljoint... I have a "retarded I'm sure" question about 2 barrel vs. 4 barrel. I kept the Holley 4779-9 off the old engine. I'd like to change the intake manifold on the new engine to fit the Holley. Is this a sound idea?
No,to much carb for a stock engine....:yes:
 

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We all have to start somewhere. So if I might offer some more entertainment to Balljoint... I have a "retarded I'm sure" question about 2 barrel vs. 4 barrel. I kept the Holley 4779-9 off the old engine. I'd like to change the intake manifold on the new engine to fit the Holley. Is this a sound idea?
Don't be shy, just keep asking.
 
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