compuvette

I just picked up an LT5 out of a wrecked 91 ZR1. I am going to drop it into my 84 vette. It's got an auto in it now and I am probably going to leave it that way. What's involved in setting up an LT5 for an auto? Flexplate and bellhousing? I'll be putting a NOS Sportsman fogger setup on the LT5 as well. Anyway, thanks!

compuvette

Just shot an email off to LPE (I'm about an hour away) to see what they would charge to set it up. Might just have them do it so that everything works.

Aaron71771

There is only one auto LT5 that I know of, not sure what is involved in doing the change over - should be a cool project tho.

A26B

NITROUS JUNKIE

There are 2 automatic 4L80e cars LPEs TT and my 415 with direct port NX. I will do turnkey conversions on the ZR1s. I dont think LPE wants to do any more auto ZR1s, but I could be wrong. If LPE doesnt want to do it e mail me. I have pounded out a lot of abuse to the 4L80 in my ZR1 with the slicks, no problems with the tanny yet. The auto is the way to go the first pass was pulling 1.6 60 foot, I think it will get even better. I will be taking mine to the track here in Denver, CO in a couple of weeks. I'm waiting on some new nitrous parts. I think I can get it into the 9s here at 5800 feet.

compuvette

Wow! I'm not going for quite that much power! I do want to run nitrous, but just a 100-150hp shot. My car came with a TH700R4 so I was thinking of getting a mega-raptor and hooking the LT5 up to that. I know there are trucks and other things hooked up to th700s. Is that an easier hookup? I'd be looking at around 500-550hp with the juice and a well built 700 can handle 600-700HP. That's more than enough for me. Hey, I only have a little over 300hp now (built L83 crossfire). The LT5 ought to be warp speed for me! I should have the LT5 by the end of June. I also am going to talk to Arcola racing engines in Fort Wayne. They were going to do the LT1 conversion on my 'vette before (have a spare LT1 and gobs of go-fast parts for it). From what I've read the tranny should bolt up (please tell me if I'm wrong!). The only kicker would be the flex plate. Will a SBC flex plate even bolt up or do I need a full custom job? Anyway, thanks for the help so far and I will keep you guys posted. Please keep the advice coming! Nitrous Junkie, I will see what I can do locally and if nobody around here can do it I will be intouch. Thanks!

Greybeard ZR1

JMHO, unless you've got the facilities like nitrous jubkie has, I think it would cost you more to do the conversion than it would to go out and buy a ZR1.

Besides, what would you have when finished? A C4 with an LT5 in it. So what?

I'd be more inclined to put it in the old shark, and put the LT1 in the 84' but that's just my opinion.

compuvette

I hear what you are saying. The 71 would be wicked with the LT5 but that's the wife's car and it is already getting a modded LT1. Can't have the wife's car be faster than mine, can I? I really like the look of the early C4 plus my 84 is in great shape. Also, I've always thought that the LT5 was about the coolest engine GM ever put in a Corvette. I'll do some research and see what it's going to cost. Figure it will be alot cheaper than dropping an auto into a ZR1 as my car is already setup for an auto. All I gotta do is hook the LT5 up to my transmission (or a better TH700). Except for the whole flex-plate/torque converter thing I can't see how it will cost a whole lot more than dropping in the LT1. Gotta love the sleeper factor too! "Oh, it's just a cross-fire.....". Yea, a 180mph cross-fire! Yes, I could probably buy a ZR1 for what I will have in this but it would be a high mile one. The engine I have only has 5K miles on it and I got it for a pretty good deal. Plus, my 84 vette just became eligible for collector car insurance this year. Costs me $124 every six months for full coverage insurance. Gotta love that! Guess I will see what it is going to cost and go from there.

Aaron71771

Personally I think an 84 with a LT5 in it would be They are great motors.

Greybeard ZR1

Yes, I think it's the greatest motor Chevy ever put in a Corvette. But my point was that the 84' is at one end of the spectrum of C4's, early and full of engineering that was constantly upgraded over the years to end up with the ZR1 which was the best C4 in every way, not just motor.

For example: Consider the 20 year old Dana 36 rear-end. How long do you think that's going to hold up behind an LT5.

Unless that 84' has a whole lot of sentimental value, I'd consider going for the whole package, seeing as they're so cheap now. Remember, an old 84' C4 with an LT5 in it ain't no ZR1.

vettl83

Compuvette this conversion has come up before, the LT5 swap into a non LT5 C4. If I recall the major issue was the ecm. You would have to figure out how make all the wiring for the LT5 ecm work in the 84. Not an easey task as the two ecm's are worlds apart. There are several LT5's out there residing in non ecm cars, but as far as I know no one has transplanted one into a non LT5 C4. As far as the rear differential goes a Dana 44 should bolt right up. However, as stated previously in this post the cost might overide the gain. Best of luck. 84 CF 91 ZR1

compuvette

Never claimed it would be a ZR1. I am just looking to drop a LT5 into and 84 Corvette and that is what it will be when it is done. The ECM shouldn't pose a major problem as the engine comes with a complete harness and an ECM. The only thing that the ecm controls on the 84 besides the engine is the fuel pump and the torque converter lockup. Should be pretty easy to get around that. Yes, I've considered just picking up a ZR1 and still might if this starts to look like too much of a hassle, but for now I am running with this as I don't think it will be too bad. Not looking to make any problems here, just want some advice. Rest assured I will not be putting ZR1 badges on the side of it. It does have AFS 5-spokes on it though......

compuvette

Yes, I've considered the life of the differential. Figure when it blows up it will give me an excuse to drop in a 44 with lower gears. I'm figuring it will last a while as there are people running insane amounts of power through them and haven't toasted them yet. I'm looking at it like this, either I can drop more money into the engine in the 84 to make it go faster or I can swap in a different engine. I have a spare LT1 laying around (in addition to the one going into the 71) or I now have an LT5. Which would you drop in? I would drop in the LT5 as it is just awesome. Yes, the LT1 would be simpler but I wouldn't get the same feeling when I open the hood or stomp on the gas. Don't you guys just like to open the hood and see that monster of an engine? Plus, I'll have something that nobody else has - an '84 vette with an LT5 in it.

compuvette

Well, the LT5 will be here at the end of June. Arcola Racing Engines in Fort Wayne is going to do the swap. They are going to machine a custom flex plate for it and don't think it will be too bad. Gonna port and pollish the injector housing and plenum while they are at it. Now I just gotta get some headers.....

vettl83

Compuvette if your looking for headers for that beast contact Brian Aspaugh at usa_won@yahoo.com he's in Newburgh, Indiana. A lot of the ZR1 guys run his headers including myself. The installation with Brians help was pretty straight forward. Found him to be a great guy to do business with. Keep us posted on your project. 84 CF 91 ZR1

compuvette

Thanks! I'll give him a shout.

PaceThis

Best of luck on the conversion...

BTW, I've seen 50k mile 90-91 z's go for $15-17k in decent shape. By the time you sold the LT5 and the 84, along with the $$ you'd spend on the conversion, you'd likely be very, very close to getting a nice z.

No one was trying to give you a hard time. We're just giving you some insight into the possibilities. If you ever have to resale the 84 with the LT5, you MIGHT be hard pressed to get 10k...which probably isn't a pretty picture. Personally, most people won't give you $1k more than a L83 for it...

If it's sentimental, go for it...but financially speaking, you might want to reconsider.

FASTAZU

Greybeard ZR1

Just a word on those headers. They need to be modded quite a bit to clear that auto trans, so don't run out and buy a set for a stock LT5. Nitrous Junkie may be able to send you some pix to help, so you could have some custom ones made up.

I didn't mean to rain on your parade. Just throwing out a few ideas about the problems you'll encounter. I hope the swap goes well. More power to you, and keep us posted.

-=Jeff=-

To put that LT5 in your 84 you will also need to:
-Get a Brake Booster from a ZR1 (they are different from Non-LT5 cars)
-modify or replace the Heter box with one from a ZR1 (again different in a non-LT5)
- I have also been told that the cradle that theLT5 bolts to is different.

Good luck