Newbie here: Don't see much about folks using an LT4 or ZF

[Guest zconvert]

Hey guys, GREAT site. I am in the initial stages and research for doing a swap. I've been lurking a while and finally registered. I'm wanting to use an LT4 motor / ZF 6-speed transmission out of a Vette but I haven't seen any posts about either that motor or tranny. I used to be a Vette guy (notice the sig) so I'm leaning toward that combo due to my experience with it being bulletproof. I've never had a T56 but I understand they are very strong as well. Also, what are the advantages to an LS1 over LT1/LT4? I was a C4 guy so I don't know much about the LS1 other than it doesn't have a distributor (which I kind of like).

 

Thanks is advance,

Kevin

[Guest Anonymous]

The LS1 is a completely redesigned small block. Its lighter, more effecient and of course more expensive to buy, but it has great power out of the box and well its considerably lighter than a LT1. Its not as easy to swap as the LT1 or early SBC or TPI motor as there is no 'kit' per se to put it in and its a tougher swap. Its far more modern though and if I had my druthers I'd use one if I could afford it. The ZF may just be to big for the tunnel, someone was going to try using it as I recall and ran into clearance issues. The T56 fits well with only slight pounding of the firewall area and right side by the reverse switch. If you use a JTR kit the crossmember will have to be narrowed or you'll need to pound about 4" on each side to get the crossmember flush with the bottom of the car. Shortening it is prefered if you have a welder that can weld 3/8" steel, I didn't so just moved the metal with a 3 lb sledge and after many blows it finally succumbed to my will.

Thats about what I know of the swap, I did a early chevy with a T56 though, others can tell you the nuances with a LT1 and LS1. Good luck and welcome.

 

Regards,

 

Lone

[DavyZ]

Welcome!

 

LT4? That's the ZR1 motor, yes? Well, I think that cost and (lack of) availability is the main reason for not using it.

 

LT1's are great engines and they don't have a distributor per se. I wouldn't consider the Optispark to be a distributor really, but I suppose it functions in a similar manner. Some like 'em, some don't.

 

Anyway, I believe the LS1 block is aluminum (someone correct me if I'm wrong here) and their availability is getting better and better. I love that, because it makes LT1 motors get even cheaper...

 

The primary thing you would have to find out about the LT4, if you are planning to go that route, is where the mounts are in relation to the standard 350 block. If the attachment points are the same, then using the JTR method would be a snap. Of course, then headers would be the next question.

 

If you have a good amount of cash to do such a swap, it would be extremely cool and very unique. If you want your dollars to go further, and wish to do a minimal amount of fabrication, then a modified LT1 is a great way to go.

 

Good luck on your swap whatever you decide!

 

Davy

[Guest the_dj]

The LT5 is the ZR1 motor. It is VERY expensive and rare.

 

LT4 is a 330hp motor based on the LT1 that was put in some corvettes and a limited edition set of 100 SS's and 37 Firebirds (I think formulas).

 

Sam

[Guest JAMIE T]

LT4 is a better LT1. Improved heads, intake, and cam. All the LT4 parts bolt on to the LT1 motors.

 

Davy, LT5 is the ZR1 engine, 32V(oh yeah!!!)

 

The ZF is a big tranny. The T56 fits better in Zcars.

 

I have a '94 Z28/6spd. I've done the top end and installed the HOT cam package, ported the heads(out flow stock LT4's), etc... BTW, the trans is the last thing I'm worried about breaking.

 

The motor and trans will find there way into a Zcar, if I ever get around to it.

[DavyZ]

Ah, ok, me understand now! Too many numbers for my aching head...I'll stick to my bread & butter, garden variety 350

 

Still, thanks for the clarification. Hmmm, an LT4 sounds like a great motor...availability?

 

Davy

[Mike C]

I think there are a couple of reasons you don't see the LT4 and ZF swap. Price and availability. They just were in a few 'vettes and SLP Firehawks relative to LT1s. The ZF trans are usually snapped up by 'vette guys. Most of us Z car types are cheap skates, looking at best bang for the buck which will be LT1 6 speed or LS1 6 speed. As far as swapping goes, the T56 is easier and cheaper, quieter and you don't have the goofy dual mass flywheel that is needed to minimize gear rattle. (Gear rattle? In a $5000+ tranny? In a $40,000+ car? How long have they been building manual trans? What's up with THAT?) It's possible to get LT4 power out of an LT1 with the LT4 HOT cam and CNC ported stock heads. The LS1 rocks, though. I'd love to have one, but now we are back to the cheap thing.

[Guest zconvert]

Guys, thanks. That was just the info I was looking for.

 

It is definitely possible to get LT4 power out of an LT1 but it was a little more than heads, cam, and intake (but that's most of the power). It didn't have EGR and had a few things to improve durability. Oh yeah, and it's painted a cool red!

 

ALL 6 speed Vettes in 96 were LT4 which is something like 6000 so they are out there - but I'm sure nowhere near the numbers of LT1 due to it being in 3 other cars!

[Guest zconvert]

Oh yeah, almost forgot, check this out for those who are interested in the differences:

 

http://www.malcams.com/legacy/misc/LT4.htm

[Guest zconvert]

One last thing the_dj - if you check the Vette boards most guys that have their cars dynoed are pulling about 345 - 350 in actuality. The theory is that GM didn't publish the actual horsepower due to the fact that the LS1 was coming out!