LS4 Transmission questions

I found a supposedly running LS4 from a 2007 Monte' Carlo and i've been learning about the "red headed stepchild" of the LS world, in particular about the transmission-facing starter. I would typically just say "huh", but recently I found a World-class T5- likely from a 1990s firebird or Camaro- at a junkyard for a song and I can't help but think this could work. Does anyone know of a bellhousing that could allow it to be bolted to the T5? Or if there's a clutch and bearing combo that could make it work? Or are the LS4's peculiar build issues too much to work around?

I'm sure you could use an adapted circle track bellhousing with the bell mounted starter... Unless it's cheaper than free for everything, just a conventional ls is cheaper and quicker.

Don't those have the 60 deg V6 bolt pattern on the bellhousing?

Furious_E said:

Don't those have the 60 deg V6 bolt pattern on the bellhousing?

It should, but it also has no provsion for a starter so it would have to be cut and welded in.

Furious_E said:

Don't those have the 60 deg V6 bolt pattern on the bellhousing?

Yes.

Also, Furious_E, last time I checked (less than a year ago), the LS4's were about the cheapest aluminum block LSx around when you look at average prices and availability..

I had wondered about the feasibility of adapting a roundy-round gear reduction starter to the underside of the "wing" on the lower left side of the block, like seen here (under the A):

In reply to bluej :

Yeah, the guy has it listed for $700 on FB Market, and I *think* I could hock it for $500 if i'm lucky. A 300HP manual aluminum V8 is tempting, even though I have no car for it lmao

Why not just keep the Monty trans and toss it all in the back of an mr2???

Or get it for me and I'll put it in the back of an x1/9

I wouldn't even bother with a LS4 or the T5 for that matter.  If it's cheap enough buy it for the 243/799 heads, flat top pistons and gen4 rods.

Now if you do want to buy that and make an LS swap difficult. You would have to figure out the starter placement and then a Solstice AR5 with a Fabbot kit and 60 degree 4l60 bellhousing might work and would be a lot more robust than a T5.

bluej said:

Furious_E said:

Don't those have the 60 deg V6 bolt pattern on the bellhousing?

Yes.

Also, Furious_E, last time I checked (less than a year ago), the LS4's were about the cheapest aluminum block LSx around when you look at average prices and availability..

By the time you adapt a transmission to it, figure out the starter issues, possibly have to change out the oil pan and accessory drive, ect I wonder whether you really would come out ahead. You can find aluminum 5.3 truck motors for around that same $700 if you look long and hard enough.

Robbie said:

Why not just keep the Monty trans and toss it all in the back of an mr2???

Or get it for me and I'll put it in the back of an x1/9

That's exactly what I'd do with an LS4.

In reply to Robbie :

Exactly. Or put it in the back of another Monte, like Hot Rod Garage did for AWD and 1000 hp.

I have a similar idea involving a FWD Modular V8 from a Lincoln Continental.

In reply to Furious_E :

It was more of a cheap access to an LS for all the things a person needs a cheap LS for- challenge car mostly, though it would be something that came together serendipitously and not by design.

I have seen a couple SS Trailblazers nearby with the aluminum 5.3- this LS4 was just something that *appeared* and not something I looked for.

In reply to GIRTHQUAKE :

Oh I totally understand, there's a $500 6.0 LQ4 (the goofy early one with the iron heads and longer crank) on FB Marketplace that's been tempting me all week. Hope I didn't come across as too pessimistic.

So here's a stupid idea, if it is just going in a challenge car: Could you just skip the starter and pop start it all the time?

Furious_E said:

In reply to GIRTHQUAKE :

So here's a stupid idea, if it is just going in a challenge car: Could you just skip the starter and pop start it all the time?

HA, BEST IDEA

You know what they say about certain brands and rear window heaters...

GIRTHQUAKE said:

Furious_E said:

In reply to GIRTHQUAKE :

So here's a stupid idea, if it is just going in a challenge car: Could you just skip the starter and pop start it all the time?

HA, BEST IDEA

You know what they say about certain brands and rear window heaters...

Get a garage door spring and a one-way hub/sprocket from a bicycle and start that beast from the front!

I love this place 

I bought my all aluminum LM4 for $300.  It's reserved for my Challenge build.

AX15 or R154 with early 2.8 jeep bellhousing

T5 with 3.8 Bellhousing

My jeep would be fun with a 3.8SC....

I know how to do it in my head, i just don't have an ls4 to try it with anymore.  Someone give me one to try it with

Furious_E said:

bluej said:

Furious_E said:

Don't those have the 60 deg V6 bolt pattern on the bellhousing?

Yes.

Also, Furious_E, last time I checked (less than a year ago), the LS4's were about the cheapest aluminum block LSx around when you look at average prices and availability..

By the time you adapt a transmission to it, figure out the starter issues, possibly have to change out the oil pan and accessory drive, ect I wonder whether you really would come out ahead. You can find aluminum 5.3 truck motors for around that same $700 if you look long and hard enough.

A proper accessory drive generally costs more than the engine.

AAAAND... I don't think you can mount a longitudinal accessory drive on an LS4.

The thin with the LS4 is, the crank is shorter at both ends, because GM was trying to find any spare millimeter they could.  I'd like to say the flexplate flange is 10mm closer and the crank snout is 15mm shorter.  That makes adapting difficult.

Now, if you're a weirdo like me, that doesn't matter since you'd be putting a 4.8 crank in there anyway, which also leaves room for either the method I was thinking of for a starter, or Patrick's method for mounting a starter, which he told me in confidence and so I will not divulge, but both are pretty simple.

Anyway it still doesn't make sense when LS4s are $700 and LM4s are $1000 and L33s are $1500.  The money you save will be blown all out the window by the time you are done.

could run a hand held starter like drag cars have.