You Vette Ya - Another C4 Build

Over the holidays not much happened with the Vette. I put 3-400 miles on it just getting to know the car a bit. It drove well, but felt pretty anemic. The 3rd gear synchro was a little temperamental, but rebuilding a ZF is quite the expensive proposition, and how often do you need 3rd on an autocross? It should be fine for the first season. In February we got serious about trying to get it in the shop to start the conversion. Between other conversion projects being prototyped and production, the first opening was the beginning of March.

Come the first of March I loaded up Ol' Blue (as we took to calling it) and headed toward the next big step in the building of the car - the engine swap.

Yep, that's the LS1 in the big crate in the back of the truck above. It's a 2001 model out of a Z28 that looked like it was hit by a train in the rear.

Once we got to the shop, we took some preliminary measurements. Things like the factory driveline angle, position of the trans in the tunnel, stuff like that. Then we started taking it apart. Boy, those factory hoods sure are heavy.

In a couple hours, we had the L98 hooked up and ready to come out.

Before we pulled it completely out of the chassis, I couldn't resist rolling the LS over for a shot of it with the L98 in the background.

The real work on the car had begun!

Tossed aside like yesterday's newspaper, the poor original L98 from the Vette faces an uncertain future.

Allright... ALLRIGHTY then, Since I live around the corner How Much for the Old News.

In reply to GTXVette:

Well, it IS an original Corvette engine and all. $$$$$$$$$$$

Actually, it might find a home in a GMC Jimmy I happen to have sitting around. But after this mess settles down I'll take stock and see what seems appropriate.

But for the car itself - the future is being mocked up. Since the trans is connected solidly to the rear diff by the C-beam, the engine location is pretty well set. Hopefully it fits. If not, there will be a good bit of fabrication involved.

A big part of the swap is the Quick Time bellhousing that adapts the ZF trans to the LS.

actually I would just be adding to the pile Ive been through a few Vettes so there not special to me. I show an unrestored 66 427 4speed car (it's not mine) and still have the one from the c-4 i am putting a TD BB with the Basics into. Not my first rodeo. you sounded like you had no use for it, it's all good.

Engine mounts were roughed in using the OEM engine pedestals.

As seen in this view from the bottom, the passenger-side head is very close to the AC box, but it fits.

A close-up view of the closeness.

In reply to GTXVette:

No worries, brother. We all seem to gather a bunch of extra parts after a few years of playing with these things. You know how it is - there's always a good use for a running small block eventually. I love the midyear cars, we should get together some time and do some bench racing.

The original thought was to use an LS3 Corvette oil pan, but it wouldn't clear the engine crossmember braces. An F-body pan does clear - but just barely. Seems to be a theme so far.

an inch would be a mile right there.... in both spots.

Hooray! Images are back.

Been away working the Charlotte Autofair for the last few days, so updates have been sporadic. Since the car is being built to run CAM-S, getting the weight down is a priority. I haven't weighed the car yet, but everything I can find puts the weight around 3300 pounds. I'd like to get as close to the 3000 pound minimum as I can (and can afford - adding lightness is expensive!)

The factory clamshell hood is a heavy sucker, over 100 pounds. I looked around and found a replacement hood from Extreme Dimensions that hooks the factory hinges, will take the OEM latches (although I might just pin it instead) and includes vents to evacuate underhood air. It also only weighs 50 pounds or so, taking 50 pounds off the front of the car. Like most aftermarket fiberglass, it'll take some fitting. But I think the weight benefits will make it worthwhile. And this isn't a show car, after all.

In reply to dkm455: That is a great looking hood!

I've buggered up 2 trying to Shorten mine,everything from the Light holes Forward are Gone but trying to bow it Inward is getting me.

Spare tire, jack and cover is about 40 lbs. Carpet and sound deadening is another 35 or so. Electric seats are chunky. Rear glass is about 35 lbs...isn't 150 lb penalty for lexan only if windshield is replaced? Running w/o roof panel saves about 30 lbs up high but I'm convinced car is noticeably stiffer with it in place. Stock exhaust is HEAVY especially rear mufflers. Popup headlights are around 30 lbs for pair....I've seen some cars with led headlights in driving lights and Popup opening glassed in.

I assume you will be running AC. what is weight difference on motor?

My c4 challenge car tipped scale at 2700 lbs with full body but gutted interior, doors and no glass other than windshield

In reply to GTXVette:

I guess you're working with the OEM hood? I was afraid to mess with the original on mine - wanted to keep it as a backup just in case, you know?

Just looking at round numbers so far - I'm saving about 75 pounds with the aluminum block LS, another 50 on the hood, at least 25 deleting the AC stuff. I should be around 125 pounds lighter with just the low-hanging fruit. I'll probably put race seats in it at some point which should save another 40 pounds or so. I'll be adding some back with the larger wheels/tires, but this is a good start. Don't think I can get to 3000 without some major, more expensive changes but I'll do what I can afford.

In reply to dkm455:

With that hood, seats, and lighter motor, elimination of stock exhaust and AC delete 3000 pounds is pretty easily attainable

In reply to Ovid_and_Flem:

That's good info, thanks! The spare, jack and all will be gone. OEM exhaust replaced with long-tube headers and a yet-to-be-determined exhaust system. The AC will be removed for sure, including the AC box in the engine compartment. It hasn't been taken out yet since the MR guys need it there to develop their kit.

I'll pull all the sound deadening I can find out, but the carpet will go back per the rules. Probably won't gut the doors yet. Would like to replace the rear glass with lexan but that's probably going to wait for version 2.0 next year.

In reply to dkm455:

IIRC manual transmission 91 c4 came in at 3240 lbs

The stock wheels and Goodyear eagles were pretty heavy so you likely will have no net gain with aftermarket wheels and tires. Also the way I read CAM S RULES specially allow removal of floor carpet unlike other CAM classes although I would make them easily put back in because that's such a pretty car you're starting with.

BTW...stock radio, if it's a Boss are very much in demand to restorers....like $500 with speakers. Anyway radio and speakers and electric antenna are another 20 lbs. Who needs a radio when you have open exhausts on an LS1

Vorshlag's c4 was in the 2900 lb rating w/o an interior and a roll cage. If i remember correctly, They had to add 75 to 100 lbs of ballast for TTC after fuel and driver. (3203 lbs).

In reply to Ovid_and_Flem:

Hmmm, I might be in better shape than I thought. That's rare!

It is a Bose system in the car - and of course it'll be removed. I wish I'd weighed the car up front. We have scales at work but I didn't drag them out and set them up.

In reply to Mad_Ratel:

I read through that blog - it was a fun read. Wonder if he sold the car?

In reply to dkm455:

Put that boss system up for sale on c4 classifieds at corvetteforum.Com...it'll pay for some go fast goodies!

I ordered a set of wheels for the Vette, and they came in a few days ago. While I'd really like a set of Forgestars or something similar, they just aren't in the budget currently. So I picked up a set of replica C5 Z06 wheels - 18 x 10.5, which will get the 315 Rival S tires on the car. The upside of the wheels is they're really inexpensive - the downside is they're about 5 pounds per wheel heavier than the factory version.

Work continues at BRP prototyping all the various engine swap combinations. The LS mounts were done first since that's what this car will actually be using. Once the headers are finalized for the LS/ZF setup, a T56 and a 4L60 will be mocked up to see what changes will be needed (if any). Then the process starts over for the LT engine. Mounts and exhaust ports were relocated on the LT - none of the LS stuff will work.

An LT/4L60 combo awaits its turn in the engine bay of the Vette. That extra hole in the side of the LT block has relegated it to a lifetime of mock-up duty.