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454 to 700r4 flywheel/flexplate

35K views 9 replies 5 participants last post by  morecubes! 
#1 ·
im trying to swap a 454 and 700r4 into my buddie's 71 malibu but running into some problems. it's a 70's 454 casting number 3999289 being hooked up to a rebuilt 700r4. what flywheel do i use?


i have one from kragen, pioneer part number FRA-141. this will bolt up to the crank flange but the torque converter holes do not line up

also have another from a sb that matches the converter pattern but wont fit onto the crank flange (center hole too small)

for those of you who've done this, what flywheel/flexplate do i use?

help please, im ready to light this thing on fire :confused:
 
#3 ·
wish i knew what the 'dual' pattern was. the bolt pattern/spacing on my converter is 9 1/4". on the BB flexplate there are two patterns, and the smaller of the two is 9 7/8" ...im tempted to elongate the holes but fear that will cause some terrible vibrations.
 
#9 ·
wish i knew what the 'dual' pattern was. the bolt pattern/spacing on my converter is 9 1/4". on the BB flexplate there are two patterns, and the smaller of the two is 9 7/8" ...im tempted to elongate the holes but fear that will cause some terrible vibrations.
The bolts aren't what center the torque converter. The converter centers off of the crankshaft.

Look at the elongated holes on these flexplates.






You can transfer hole location from one flexplate to another by laying one over the top of the other or with the flexplate attached to the engine hold up the converter up to the flexplate and transfer the hole location from the torque converter to the flexplate.

Note: There are 6 raised mounting pads. Only three are needed. Rotate the plate 1/6th of a turn and drill on the blank pads.
 
#4 ·
I just ran into this same problem, I found that if I went to the local car quest auto parts and told them I needed a flex plate for a mid 80s Chevy pick up with a 454 I would get the flex plate with the large converter bolt pattern only but, if I told them I had a 1972 Chevelle with a 454 I got a different flex plate with both large and small converter patterns. Hope this helps sorry I dont have the part# I threw out the recipt so the old lady would'nt find it. :D
 
#8 ·
Center of one hole to the center of the next is 9 & 1/4 inches
 
#10 ·
i was more concerned w/ vibrations from being out of balance if i elongated the holes. im aware the tc is centered off the crankshaft. good news, i found one that works. Pioneer part #FRA-111

bolting it up as we speak
 
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