how close is the LS4 block to the LS9 block? would it be feasible to bolt a heavily built 4t-65e tranny to the LS9? is it possible? i dont care if its recommended or not. just trying to cure my curiosity.

 

ZR1 motor, basically a supercharged LS3. And a built 4T65E-'HD' is mounted to an LS7, going into a Fiero, so it may work.

I think a 6T75 may be a better mate, but that's a field I don't know much about.

 

You'd need the shorter crankshaft from the LS4, so you'd lose some displacement. Also, accessory drive may be different.

Just not sure why anyone would want a 600+ HP front-driver. The cost alone would make it a non-starter for most people.

 

Why not? Supercat's is likely over 600. My goal is to be in that wheelhouse as well.

 

Too each, their own. Not looking to offend. I once a built a V8 Fiero, so I guess I have nowhere to talk!

Just saying that, once you've bought a crate ($23,495 from GM) or even used ($15,000 on ebay) LS9, and then do all the mods to make it fit and live in this application, you could have bought any number of other things that would still spank it. And even then, it would still be compromised by the fact that it's FWD.

I applaud anyone who wants to be different, but if you think this one through, and look at the cost/effort, it may not seem so cool after all of the checks are written. I know I felt this way after I did my V8 Fiero. Spent nearly $14,000 to do it right. It was fun when it wasn't destroying transmissions, and I wound up selling it for about $6000. If I could do it again, I probably wouldn't...Or maybe I'd just do an LS4 like Fieroguru!

 

Like stated above, the transmission bellhousing bolt pattern on the LS4 is the FWD style and the other Gen IIIs and Gen IVs use the RWD bolt pattern. The Fiero guys typically make adapters when attempting a similar swap.

The crankshaft is also an issue. You would need to use the stock LS4 crank or have some custom machine work done on the stock LS9 crank. You'd probably want to work with an old-school speed shop for something like that, as the late model guys typically focus off the shelf parts, porting, power adders, tuning, etc.

The final issue is the front accessory drive. We have a complicated single belt system that is not compatable with that blower drive, and there isn't much clearance to work with. Without major modifications to the body structure you cannot fit a two belt accessory system. I see this as the biggest issue, and one that would likely drive you to doing an N/A or turbo'd LS3 build.

Either way, I see this idea as a labor of love in the quest for uniqueness, not a cost effective way to go fast with this platform.

 

Yeah, I'd turbo, cam, and spray it, before I'd ever think of buying a crate engine and having to fabricate everything.

I have a friend with a 600 whp VW Jetta, it's different and awesome.

 

Now, turbo/cam/spray does make sense to me, like you said...You don't need to spend thousands of $$ in fabrication to get it to work.

 

It would be faster than dropping in an LS9 or LS7, too, anyway. Well, should be.

 

Come on guys, it was a curiosity thing. Kinda like when jay leno twin turbo'd that toronado.

 

if you have the $$ to buy an LS9 you might as well do a RWD conversion.

 

theres a guy on my other forum who built a monte with a ls7, turbod and it was still fwd. i posted it in another thread. if you can imagine it, it can be done. budget permitting.

 

anything can be done with the right amount of money.

 

i agree mostly with ls1 racing posts. sometimes common sense is best ? now if your in jay leno's class [big bucks] go for it why not ,its only monies ! rkvette