TurboZ28408

iTrader: (18)

i've tried the automatic forum to get this info but no go. I figure the Drag tech forum is the way to go because most of you are TH400 based vehicles.

I have a 99 LQ4, with a COAN 400 ready to put in.

Im trying to find out what flex plate I can purchase to put in? So far i believe a Flat flex plate out of the LQ4 6.0 4l80E will work with a standard SBC style torque converter.

Will any modification need to be made for the pilot bearing snout ?


Also, i'd rather go SFI approved flex plate, but do not know which flex plate to purchase. If i purchase an LS1 version, itll be curved and the wrong install height correct ? any help would be GREATLY appreciated !! I've searched ls1 tech and googled bunch of stuff. Nothing of help !!

67SS509

iTrader: (25)

With the long snout crank just get the flywheel for a 400. Trial fit and make double sure the converter pulls forward enough per manufactures specs. These LS engines will not tolerate any extra pressure on the thrust bearing.

TurboZ28408

iTrader: (18)

so a 168 tooth flex plate from tci or summit or whichever should do just fine ?

what about the starter ? will it work just fine also ? or will I have to source a truck version or somethign

camscam02

iTrader: (21)

Like I told you on norcal and gave you a thread, they DONT make a SFI flywheel that works with that crank.

You are stuck with the flat 6.0 one.

goodluck.

TurboZ28408

iTrader: (18)

you did which nor cal ? lsx or 1320 ?

camscam02

iTrader: (21)

yup on your forsale thread on lsx. go ahead and look at it. some good info.

DanZ28

iTrader: (5)

Get a hold of "ninetres" on here, he had that same crank and went through alot of BS with it. If anybody knows, he will.

TurboZ28408

iTrader: (18)

just did and he's telling me to just swap out cranks

DanZ28

iTrader: (5)

Yeah, I thought thats what ended up happening with him too...

67SS509

iTrader: (25)

Someone educate all of us here. What specifically keeps the long snout crank from working. I'm using the 4L80 flywheel and spacer with a powerglide and works fine. So what's different about the long snout crank without the spacer? I thought the only difference is the spacer. Also, is the hole in a 400 flywheel bigger or smaller than the 4L80?

Shawn @ VA Speed

iTrader: (3)

ATI makes a flat flexplate-it comes with a spacer for the short crank-just dont use the spacer.The sbc converter will work just fine with this setup as the crank pilot size is the same

TurboZ28408

iTrader: (18)

im pretty new to converters. lookin at a pro torque I have here. does the pilot extend to hit the crank and transfer power that way ? i imagine this is how the converter works. the pilot in the converter looks to fit inside the LQ4 extended crank perfectly. No pilor bearing or anything of the sort needed there right ? Unfortunately, i've always been a stickshift guy and never auto

Shawn @ VA Speed

iTrader: (3)

you want the pilot of the converter to go into the crank to guide it but not bottom out in it.