LS to older trans

[Jstock85]

The hole that happens to be not used on the back of the LS block is exactly where my trans fluid dipstick from the th350 was held on my SBC. Can I just thread the unused hole on the trans bell house and bolt the dip stick in the same place? Or is there another way? Whats everyone else doing that kept the older style trans?

[71cadc10]

I think I would tap the bell and use a very short bolt

I wouldn't risk drilling a shallow hole in the block, because I don't really know how far it is till water. Must be fairly close or GM would have put the hole there.
unless you have a junk block to do a test on

[davepl]

I am not a guru and I cannot solve this problem but will raise one just to make sure you're aware of the issue.

Between "classic" big and small blocks and the LS motor there is a difference in how far back the face of the flywheel is vs the old motors. It is .450 less further back, I think.

So, to run my LS3 with my old Hayes clutch and TKO-600 trans that come straight off the 502 big block, "all" I had to do was buy a special GM flywheel that is .450 thicker than normal. That is GM part number 12561680 and runs over $400 and there apparently cheaper ways do it with a truck flywheel, etc, but I don't know the details.

So, when I saw "LS to Old Trans" I figured I'd better post this little nugget! What I wouldn't have paid for the knowledge in the previous paragraph, would have saved me some time!

[Jstock85]

Yes def not going to tap the block. Just curious if anyone else was using the bell housing like I am thinking about.

[Jstock85]

Dave you are correct. I took a dished flex plate from a 4.8 and used to self centering ring. Yes it is complicated I did a ton of research on this same topic.

[Kudzupatch]

First thing that popped in my head was to use a flat head screw (bolt). Countersink the face of the unused hole in the transmission for the screw. Put a thin jam nut on the back and with the threads sticking out past it you have stud to mount on.

[Jstock85]

Thats a good idea. I may give that a shot first. Thanks!

[sprint_9]

Im running a 4l60e but the dipstick Im using was an aftermarket one that utilized that hole. I cut the bracket off and flipped it around to go to a head bolt hole. Held everything in place and hit it with a quick tack, once it was positioned good I welded it solid and painted it.

[gringoloco]

ICT Billet makes a bracket that bolts to the head and locates a mount in the stock location

[Jstock85]

I guess I should have done a follow up post but I found that bracket on amazon for $20 and ended up going with that.