Flex Plate or Converter for Lightning swap

iron horse · #1 08-25-2003, 11:11 AM

Will be installing a 2000 Lightning (L) engine/supercharger (only) in my 99' F-150 4.6 with the 4R70W trans.

It is my understanding that the L engine has an 8 bolt flex plate with 6 holes for the L torque converter. My 99' F150 4.6, supposely has a 6 bolt flex plate with 4 bolts for the torque converter. I need to bolt the L engine up to my 4R70W trans. Which of the following do I do:

1. Use only 4 of the 6 holes on the L flex plate and bolt the flex plate to my 4R70W torque converter (are the holes configured in a pattern that will allow this?); or

2. Find an 8 hole flex plate with 4 holes to bolt up my 4R70W torque converter (if so, what model flex plate should I look for?); or

3. Attach a L torque converter to my 4R70W trans. and bolt the L torque converter to the L flex plate.

Thanks for any assistance.

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Factory_Tech · #2 08-26-2003, 01:16 AM

4) get a 4R100 with a 6 bolt converter.

A 4R70W would have a short and unhappy life behind a S/C 5.4. The 4R100 had to be beefed up for that motor, even a regular 4R100 won't last behind it.

G

iron horse · #3 08-26-2003, 12:16 PM

Thanks Factory Tech for the tech support.

The problem with using the lightning transmission is that, I would have to change the wiring harnesses and pcm and have my truck towed to a ford dealership to have the PATS system re-programmed, just so that I could use the ignition key.

I was hoping I could get an f150 8 bolt 5.4 or 4.6 windsor flexplate with only 4 bolt holes for the 4R70W torque converter. Then, if it all worked, I was going to look for a re-built 4R70W that could handle the lightning engine torque or get a "lower torque multiplying" torque converter........what do you think?

Note: You can get an 8 bolt flexplate with 4 bolt holes for the f150 4R70W torque converter.

Factory_Tech · #4 08-27-2003, 04:30 AM

All 4R70Ws are 4 bolt, and you can get a 5.4 with a 4R70W so it's shouldn't be a problem getting a flexplate. I'd try junkyards, they're not uncommon.
I still think you'll kill the tranny, while you're at a junkyard, look at a 4R70W and then look at a 4R100, the one that looks like a toy in comparison is the 4R70. Really, the Lightning model is a beefed up 4R100, stock.

G