Flywheel cover doesn't fit

[master 1969 c10]

I I have a Chevy Turbo 400 modulator is in the back of transmission and transmission pan is the shape of 400 pan. I bought aluminum one about 5 years ago and the holes don't line up the holes the holes close to the transmission is 10 inches Center to Center and I took the cover to jegs and the one the had came up the same measurement of the one I have so it doesn't fit either and there is no spacer adapter on the transmission the bellhousing is a direct bolt-on to the motor has anybody else ran into this problem did one or two years of the Turbo 400 have a larger flywheel pan bolt pattern. My truck is coming along but it seems like I take one step forward two steps back. The top holes are about 1/2 inches off needs to be longer. Thanks Doug

[B. W.]

Post some pics if you can.

[geezer#99]

X2 on pics!
Turbo 400 has modulator on the side.

[master 1969 c10]

Pictures

[geezer#99]

So, your modulator is on the side like a turbo 400.
I found a designation for a 3L80 tranny of 1990 and up vintage.
Perhaps the tranny is from a hd motor.
Does the cover you have fit except for the bolt holes?

[master 1969 c10]

Yes, it fits. The Cover just needs to be a like 3/8 longer or so

[geezer#99]

Which holes aren't close?
Are you adverse to drilling and tapping new holes.

[100%Chevy]

There are at least 2 different T-400 flywheel dust covers.
1 for the small block engines and 1 for the bigblock engines.
Do you have a big block engine?
The difference in the covers is where it goes on the rear main of the oil pan.
A smallblock cover on a big block will be about 3/8" too short to fit right.
May be you're problem.
Mike.

[master 1969 c10]

Thanks for all the help. I have a chevy sbc 350 for the motor . And all the holes don't line up.