need help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**truckdude239** · 01-25-2006, 12:20 AM

okay so i ended up buy a remanded 350 4bolt main from advance auto for 960 buxs the guy installing it will not install it unless i get a new flywheel he says that the flywheel on my 307 is different from the ones that go on the 350 and says that my 307 start will not start a 350 i think different. some please confirm that my parts will bolt up

sdkid · 01-25-2006, 01:03 AM

According to napaonline dot com, they take the same flywheel. I think most sm chev are the same. You'll need to find out what the specific problem is with the old one.

**truckdude239** · 01-25-2006, 01:06 AM

all he says is it is a different style i the motor i ordered was for a 1971 c-10 with 350 4 barrel with 4 bolt main i was looking at advance auto and it also shows same flywheel and same starter guess i will show himt his in morning

dwaite72lnghrn · 01-25-2006, 06:58 AM

Are you sure you didn't get a 350 with a 1 piece rear seal? The crank flange is different on them. Other than that I thought they were the same.

jsbgump · 01-25-2006, 12:18 PM

As long as it is not a 1 piece rear main seal motor, the flywheel and starter will be the same.

mrein3 · 01-25-2006, 01:44 PM

In 1989 I rebuilt a 350 out of a mid-70's Monte and put it in place of my 1972 Chevelle's 307.

I was working at a shop back then so I had access to a hoist where I did all the work.

So I get EVERYTHING hooked up. I check everything twice as this was my first project like this solo.

I put the car down on the ground and hit the key -
All I heard whas the starter moter spinning freely.

Yep. The 307 flywheel was smaller in diameter that what I needed.

A trip to Midway Chev and $50 later I had that engine running with a brand new GM flywheel on the back of it.

Chris H · 01-25-2006, 01:55 PM

If I understand things correctly, there are only 2 flexplates available for the small block chevy engine with 2 piece rear main seal:
A 153 tooth (12.75") and a 168 tooth (14"). The 400 small block motors have a unique counterweighted flexplate, and I am ignoring those for this.

I think the starter is different depending on which motor is used, and as long as both the starter and flexplate from your 307 are used on your 350, you should be good to go.

A quote from Sallee Chevrolet website: "The starter must be matched to the flywheel or flexplate diameter when installing the Premium ZZ383/425 engine. Small diameter flywheels are 12-3/4” and have 153 teeth. Large diameter flywheels are 14” and have 168 teeth. This difference in flywheel diameter requires two different starter housings. Starter noses used with 14” diameter flywheels have two offset bolt holes; starters used with 12-3/4” flywheels have bolt holes that are straight across from each other."

**truckdude239** · 01-25-2006, 02:16 PM

when i looked up the 71 c-10 with 350 it calls for the same flywheel as the 307 the 168 tooth flywheel i guess i will get him to try anyway

01-25-2006, 12:20 AM	#1
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	need help okay so i ended up buy a remanded 350 4bolt main from advance auto for 960 buxs the guy installing it will not install it unless i get a new flywheel he says that the flywheel on my 307 is different from the ones that go on the 350 and says that my 307 start will not start a 350 i think different. some please confirm that my parts will bolt up __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

01-25-2006, 01:03 AM	#2
sdkid Registered User Join Date: Sep 2004 Location: Pierre SD Posts: 1,533	Re: need help According to napaonline dot com, they take the same flywheel. I think most sm chev are the same. You'll need to find out what the specific problem is with the old one. __________________ I think the world needs a drink... Help somebody...If you can....VanZant We're not wrong, we're not sorry, and its probably gonna happen again. That's the truth about men. Tracy Byrd Member# 13924 '70 c10, 350/350 '68 c10 250/4spd '68 c10 no eng/trans fac ps/pb/ac/at (future father/sons project) '48 Chevy Loadmaster Last edited by sdkid; 01-25-2006 at 01:04 AM.

01-25-2006, 01:06 AM	#3
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: need help all he says is it is a different style i the motor i ordered was for a 1971 c-10 with 350 4 barrel with 4 bolt main i was looking at advance auto and it also shows same flywheel and same starter guess i will show himt his in morning __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

01-25-2006, 06:58 AM	#4
dwaite72lnghrn Registered User Join Date: Jun 2002 Location: central pa Posts: 1,525	Re: need help Are you sure you didn't get a 350 with a 1 piece rear seal? The crank flange is different on them. Other than that I thought they were the same. __________________ 72 longhorn c30 502BB/th400/fact air/4.11rear/ custom camper 72 bug(the better half's) under reconstruction 2009 HHR aqua blue 71 GMC k20 350/sm465 2009 Chevy hd3500 6.6 Victory Red crew cab dually Dave & Jeanne

01-25-2006, 12:18 PM	#5
jsbgump Gone Fishing Join Date: Aug 2005 Location: Fort Worth, Texas 76135 Posts: 12,361	Re: need help As long as it is not a 1 piece rear main seal motor, the flywheel and starter will be the same. __________________ 68 Chevy Short Fleetside LSX Swap Under Way 3.73 posi 2.5/4 drop Frame of resto has been started 2022 Hyundai Tucson Limited 2019 Chevy Traverse Redline Edition Wifes Ride Build Thread http://67-72chevytrucks.com/vboard/s...=1#post3483616

01-25-2006, 01:44 PM	#6
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,253	Re: need help In 1989 I rebuilt a 350 out of a mid-70's Monte and put it in place of my 1972 Chevelle's 307. I was working at a shop back then so I had access to a hoist where I did all the work. So I get EVERYTHING hooked up. I check everything twice as this was my first project like this solo. I put the car down on the ground and hit the key - All I heard whas the starter moter spinning freely. Yep. The 307 flywheel was smaller in diameter that what I needed. A trip to Midway Chev and $50 later I had that engine running with a brand new GM flywheel on the back of it. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

01-25-2006, 01:55 PM	#7
Chris H 72 C30 Trailer Queen Join Date: Dec 1999 Location: SE MN, USA Posts: 794	Re: need help If I understand things correctly, there are only 2 flexplates available for the small block chevy engine with 2 piece rear main seal: A 153 tooth (12.75") and a 168 tooth (14"). The 400 small block motors have a unique counterweighted flexplate, and I am ignoring those for this. I think the starter is different depending on which motor is used, and as long as both the starter and flexplate from your 307 are used on your 350, you should be good to go. A quote from Sallee Chevrolet website: "The starter must be matched to the flywheel or flexplate diameter when installing the Premium ZZ383/425 engine. Small diameter flywheels are 12-3/4” and have 153 teeth. Large diameter flywheels are 14” and have 168 teeth. This difference in flywheel diameter requires two different starter housings. Starter noses used with 14” diameter flywheels have two offset bolt holes; starters used with 12-3/4” flywheels have bolt holes that are straight across from each other." __________________ Chris H 72 C30 133" 72 C30 157" flat-dump 69 C10 short fleet 71 ElCamino 2000 K2500 crewcab shortbed (sold, sorry old friend) 2005 GMC 2500HD shortcrew Duramax 2006 K1500 RCSB and a couple other projects/parts

01-25-2006, 02:16 PM	#8
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: need help when i looked up the 71 c-10 with 350 it calls for the same flywheel as the 307 the 168 tooth flywheel i guess i will get him to try anyway __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube



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