Does my transmission mount have to move?

Clutch, transmission, rear axle

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F100builder
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Does my transmission mount have to move?

Post by F100builder »

Perhaps this has been answered a dozen times but I couldn't find a definite answer after searching. I'm installing a 390/C6 combo into my '70 2WD SWB which originally had a 240/3-sp. on the column. Are the 3-speed manual and C6 cross members the same? If not, can it still be used for a C6 and if so, does it need to move back in the frame? I could go look at my '69 with its 390/C6 but the previous owner never moved the engine towers back from the 240 location during its swap and the truck came with a spare cross member in the bed...I haven't really ever compared it with the one in the truck now.
I was just hoping someone knew off the top of their head. If not, I'll grab my tape measure and go get my hands dirty in the morning! Thanks in advance. :D
Patrick

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'56 F100; Must.II IFS, 351W bored & stroked to 395c.i. 470hp/483ft-lbs., AOD, 4-link coilover 9" w/ 3.89's
'69 F100; 390, C6, Dana 60 w/ 4.10's
'70 F100; 'new' and latest project soon to have a built 390/C6 and 3.50 gears
To see more of my F100's: http://www.cardomain.com/id/lowfat56
Whateverman
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Re: Does my transmission mount have to move?

Post by Whateverman »

the crossmember is the same,you'll most likely hafta move it in my ol'pig i've had it mounted in a different spot for each different trans i've had (c6,c4,& np435)
- still got my first first car 20+yrs later : 69 f100 sorta kinda pretending its a Mercury M100 w/a 70 f350 sport custom cab (factory buckets) 67 grille with 69 ranger cooneyes 68 merc box and hood,some supercool fiberglass fenders i scored way back when, 76 f150 disc brake frontend..currently running a 90 5.0HO 4bbl/c4 auto & 3.50 posi...originally a 360/c6 f100 Ranger with dealer added towpack (incl. kelsey hays trailer brake),boxside toolbox,behind the seat stowage & belly tank...only original parts left on 'er are the frame,rear end,rear springs,and rear bumper...
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Brokenarrow
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Re: Does my transmission mount have to move?

Post by Brokenarrow »

F100builder wrote:Perhaps this has been answered a dozen times but I couldn't find a definite answer after searching. I'm installing a 390/C6 combo into my '70 2WD SWB which originally had a 240/3-sp. on the column. Are the 3-speed manual and C6 cross members the same? If not, can it still be used for a C6 and if so, does it need to move back in the frame? I could go look at my '69 with its 390/C6 but the previous owner never moved the engine towers back from the 240 location during its swap and the truck came with a spare cross member in the bed...I haven't really ever compared it with the one in the truck now.
I was just hoping someone knew off the top of their head. If not, I'll grab my tape measure and go get my hands dirty in the morning! Thanks in advance. :D
I did the same swap on my truck. If you mean the transmission crossmembers, they are different, one is offset & the other is centered. Either will work but you may have to drill new holes in the frame if you use the standard crossmember. Also these trucks have two different "humps" in the transmission tunnel. Mine has the small hump & the C6 is very close to the floorboard. It works but bolting/unbolting the transmission mount is a PIA . Here's a pic showing the difference in the crossmembers.
Image
'68 SWB f100, 401ci FE/C6, '68 Mustang fastback (restoration in progress)
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2013 F150 KingRanch (ecoboost), '48 8N tractor


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F100builder
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Re: Does my transmission mount have to move?

Post by F100builder »

Thanks for the reply and photo! I will be cutting the transmission tunnel out like a C6 truck and I have an extra C6 'hump' to bolt in place. :thup:
Patrick

ImageImageImageImage
'56 F100; Must.II IFS, 351W bored & stroked to 395c.i. 470hp/483ft-lbs., AOD, 4-link coilover 9" w/ 3.89's
'69 F100; 390, C6, Dana 60 w/ 4.10's
'70 F100; 'new' and latest project soon to have a built 390/C6 and 3.50 gears
To see more of my F100's: http://www.cardomain.com/id/lowfat56
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Brokenarrow
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Re: Does my transmission mount have to move?

Post by Brokenarrow »

F100builder wrote:Thanks for the reply and photo! I will be cutting the transmission tunnel out like a C6 truck and I have an extra C6 'hump' to bolt in place. :thup:
It will work without cutting and the extra floorboard space is nice.
'68 SWB f100, 401ci FE/C6, '68 Mustang fastback (restoration in progress)
Image
2013 F150 KingRanch (ecoboost), '48 8N tractor


"Be more concerned with your character than your reputation, because your character is what you really are, while your reputation is merely what others think you are."
— John Wooden
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F100builder
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Re: Does my transmission mount have to move?

Post by F100builder »

I'm installing a floor shifter though and I'd like to have better access.
Patrick

ImageImageImageImage
'56 F100; Must.II IFS, 351W bored & stroked to 395c.i. 470hp/483ft-lbs., AOD, 4-link coilover 9" w/ 3.89's
'69 F100; 390, C6, Dana 60 w/ 4.10's
'70 F100; 'new' and latest project soon to have a built 390/C6 and 3.50 gears
To see more of my F100's: http://www.cardomain.com/id/lowfat56
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