Motor Mount Options? How much can I re-position the engine?

[Norcalz71]

Ok so regarding motor mounts, i seem to be getting some mixed reviews.

I have a 10" lift on my truck, so I have already dumped a decent amount of $$ into modifying driveshaft lengths once. I know that the 4l80e is longer than the 4l60e so if i just swapped an 80e in, i would more than liekly need to shorten my rear shaft and lengthen my front shaft.

given this issue, what are my motor mount options (including maching my own, definitely capable of this) in moving the engine forward enough to compensate for the added length of the 80e? I plan on running e-fans and by looking at pictures it seems like there "should" be enough room to build some motor mount adapters which will scoot the engine forward far enough that the actual output shaft on the 80e remains in relatively the same position front to back as the stock 60e was, thus eliminating need to modify driveshafts again.

thoughts? will I be able to move the engine assembly far enough forward to compensate for the longer overall length without having interference issues with the front engine accessories and the fans/radiator, and not having things be absurdly cramped up front?

[567234ta]

sounds like a lot more work than just cutting a driveshaft but i dont know how much longer a 80e is anyways. maybe someone here will chime in.

[Norcalz71]

sounds like a lot more work than just cutting a driveshaft but i dont know how much longer a 80e is anyways. maybe someone here will chime in.

well i only ask because i know depending on what mounts you use, it sets the engine in a slightly different position. i think the 80e is ~1.5 inches longer, give or take, so if i could get the mounts to position the engine about 3/4 - 1" forward of "stock", then i just need to move the trans cross member forward a bit and all should be good. assuming everything will continue to clear just fine and its just a matter of machining the motor mount adapters slightly different, then it will save me the cost of modifying 2 driveshafts again.

[567234ta]

yeah with 2 shafts that may be your best option, did you read the swap thread on the 4l60E to 4l80e conversion?
http://www.ls1truck.com/forums/front...rans-swap.html

what year truck is it you have?

[Norcalz71]

mine is a 94, will be likely getting an 02 6.0/4l80e. ill have to take some measurements, but if i can keep the tailshaft/housing of the 80e in relatively the same spot as the 60e was, that should allow me to keep both driveshafts i have now. i think my only problem would be having enough slip yoke range of movement without interference

[567234ta]

i have a 96 4x4 and when they put the 6.0 80e in they didnt have to change anything, it fit right in.

[Norcalz71]

pushing a motor forward will event handling along with weight transfer. i know your lifted but will have neg effects on your truck. also with more weight forward it will play a toll on brakes

in the grand scheme of things though, and the fact that i drive like a grandma, is shifting the engine 1" forward at most going to ruin everything? i cant imagine its even close to as bad as running a heavy front winch bumper.

[Norcalz71]

1" shouldnt be an issue but it might give ya problems with headers.

is anyone making LSx engine longtube headers that fit the OBS yet?

btw i can offset the weight up front with my fullsize 38" spare in the bed :crazy:

[blander66]

if it is only an inch difference your drive shafts should have enough slip in them to compensate. If not at least for the rear you could use a zero rate and move the axle back 1 inch that would help your departure angle

[Norcalz71]

well im thinking that with the addition of an 80e, my friend had to change his driveshafts due to overall length increasing. by slotting the engine forward 1", it would hopefully offset the change enough to not need driveshafts. i would use a zero rate but i'm actually lowering the rear down a bit and its a total street queen so i want to keep it centered in the wheel well, no real need for good departure angle