Davy_Baby9

iTrader: (23)

So I bolted up the flexplate and spacer today to my motor. And I went to install the converter, and only 1 of the holes lined up. This doesnt seem right to me? So I marked where the other 2 holes would go, but why would I have to drill? I know I have the correct converter.

Flexplate: 12551367
Hughes 700R4 lockup 3000 stall

Here are some pics...




EDIT:> I actually cut the holes and everything looks like its going to line up. Do you think I will run into any problems with this?

Davy_Baby9

iTrader: (23)

heres the other picture, I already drilled where the red dots are, and everything looks like it will bolt up correctly. I just dont remember in any of the ls1/700r4 threads that people had to cut the flexplate??

dca1042

line up where original convertor went on recessed pads.redrill through there.if you dont do this,bolts may foul on back of block.....just be careful...

cheers dave...

jay_lt4

iTrader: (4)

you have a 6.0L flat flexplate, that only has the pattern for the large th400/4l80e on it, you need the smaller th350/700r4 pattern

if you drill in the spots you have marked you will be pulling the converter out of the trans more than you need to,,

if you get yourself a curved 5.3 flexplate and swap the spacer from behind the flexplate to the front of it you will only need to slightly dremmel out the converter holes for them to line up correctly

trust me, i have done several swaps and have used both the flat and curved flexplates

Davy_Baby9

iTrader: (23)

Is that pretty much the only route to take now? I was going to see if redrilling on the bumped out spots would work...

I just hate pulling stuff back apart after I get them together.

Otherwise I will order a 5.3 flexplate Monday.

jay_lt4

iTrader: (4)

yes you can try to drill on the mounting pads, that would be the only solution for the parts you have already

Davy_Baby9

iTrader: (23)

I was just looking, and I really dont like the way it is going to look. For it to work, I would be making the holes on the mounting pads twice as long as originaly...

I would be worried to converter would slide under heavy power, but I really dont know what Im talking about, thats why I make these stupid threads lol.

Davy_Baby9

iTrader: (23)

What sucks is that this is what the GM Conversion manual told me to do.

Quote from the manual. "the converter mounting holes must be modified for use with Gen 1 and Gen 2 converters with 298mm bolt paterns"

jay_lt4

iTrader: (4)

correct, but they are talking about the 5.3/ls1 flexplate,, your holes are off so far because it is a 6.0 flexplate with the th400/4l80e pattern on it

if you started with a ls1 or 5.3 flexplate the holes are not that far off and can be dremmeled easily to fit

Davy_Baby9

iTrader: (23)

The quote came from the 4L80E flexplate.

So if I get the "Dished" flexplate PN 12563136, and bolts PN 12553332, no excessive cutting would be required? So the new flexplate would bolt to the crank, then I would put on the spacer?

jay_lt4

iTrader: (4)

yes if you go with the dished flexplate you only need to oval out the holes a little. yes the dished flexplate goes on the engine first , then the spacer, the bolts you have on it now should be fine, they are longer for the spacer

LS1MCSS

iTrader: (18)

Take the convertor to a parts store and tell them you want to look at a flexplate for a 98 LS1. I believe it will have two convertor patterns and one will be correct for your convertor. I have one in my car and didn't have to re-drill anything.

Davy_Baby9

iTrader: (23)

Hey Jay, quick update.

I got the 5.3 Plate and spacer all bolted up.

The holes line up ALOT closer now. If I bolt it up to the actual mounting plates, I would have to cut about 1/4" off each hole. Now I rotated the converter and it lines up perfectly to the other set of holes that are on there. I know there not the mounting points, but what exactly are they for? The red arrows represent what Im talking about.

Another thing, there is space between the converter and the flexplate when pushed all the way back. Did you guys use some kind of washer in between?

Sorry for all the questions again...

Davy_Baby9

iTrader: (23)

Bumps for more information please.

65skyturbo

iTrader: (6)

You shouldn't have to space the converter with washers. The converter does not sit all the way back to the trans pump but gets pulled into position when you bolt it to the flexplate. BTW, what part number did you use for the 5.3 flexplate? The reason I ask is it doesn't look anything like my 5.3 plate.

Davy_Baby9

iTrader: (23)

Ah, gotcha, that makes more sense now.

And there was no part number for the flexplate. I bought it off a member here who said it came off of a 5.3 truck. It defenitly wasnt the same as the 6.0 plate, and we compared them. This plate is "dished" just like they said.

So is it a good idea to bolt the converter to the holes that line up without any cutting or just mount it to the actual mounting holes but have to cut alittle?

ssvolvo

I'm quite sure the 5.3 and 6.0 crankshafts have different spacing. Ever seen a 5.3 with a manual trans from the factory? Me either.

jay_lt4

iTrader: (4)

i have used the holes you are talking about before, some flexplates have them, i just measured 3 washers for the same thickness and put them between the converter and flexplate to make up the difference from not being raised like the actuall mounting point