The Fifteen Dollar a Day Diablo is based on a 77 Cadillac as a donor car. For those of you interested in Fiero conversions instead, Nathan Galloway, a website member from South Carolina, has been kind enough to submit the following information and photos in order to assist you.
FIBERGLASS: THINGS TO LOOK FOR AND LOOK OUT FOR. When picking out your body don't be stingy. You may find a body kit that costs 12k but comes with EVERYTHING including hinges, gauges, weather stripping, window frames, etc. and another body by itself may cost 7-8k for only the fiberglass. But, chances are you'll come out about the same when all is said and done. If you only get the fiberglass you are going to have a terrible time finding, making, adjusting, and building an entire car. Click here for the complete text
"How to stretch a Fiero". You really want to find the best donor. If you think about it, that's really what you'll be driving after all. Click here for the complete text about picking a donor car.
Here is a fairly accurate overlay of a Fiero and a Diablo. You will notice the stretch has been assumed. This will give you a general idea of the trim work needed to make the chassis fit (mainly in front and roof).
The first step in a Fiero stretch is to obviously remove all of the body panels. Remember to remove them with care. If done correctly, and by finding the right buyer, you can get almost all the money you paid for the donor back (take advantage of eBay). You need to take the engine and trans out to work on the cradle. Click here for the complete text
Before cutting or stretching make sure you have removed the engine along with the radiator hoses , shift cables, fuel lines and brake lines. These parts wont make the stretch by themselves and will have to be extended. (but that's another lesson) ALL Right !!!!!!!! Now comes the FUN PART. Once you have pulled out your level and made sure you level vertical and horizontally and what will be both parts of the body are secure, (the front with 4 jack stands the rear with jacks stands and a jack for later.)
You want to scribe or draw a line 5 inches behind the firewall and go straight down the chassis. The cradle is cut is between the bolt that holds it on the chassis and the one that goes to the control arm. Its about 1.5 inches from the end of the cradle. It is very important to take a ton of measurement and test for levelness before and during both the cutting and stretching process. A good place to test for level is on the firewall. Click here for the complete text
Now that you have two sections of car and are all lined up and are the correct distance etc., it is time to begin welding. You should have pre-made your extension kit. It basically consists of 2 (2"x2"x16" ) pieces of square tubing and 2 (2"x1/8"x18") pieces of flat steel for the top extension (obviously one set for each side). 4 (2"x2"x16") pieces of square tubing and 2 (4"x1/8"x18") flat steel for the middle sections. Two of the pieces of square tubing will go together with one piece of the 4" flat welded to the other side for added stability. And, finally, 2 (1"x3"x14") for the cradle.
There is a reason the lengths are greater than the 11 inch stretch we need. To add strength we are going to make a kind of flange, edge, lip, bracket end. I don't know what to really call it but check out the diagram. Just make sure the top stretch is 11 inches with the rest of the steel equally distributed on both ends. Click here for the complete text
After we were satisfied with that, Bobby (my mechanic, friend and savior) rolled the lips he created to match the chassis just like the rolls in the factory chassis elsewhere. He did this on top middle and cradle stretches. Click here for the complete text
The angle will be determined by the 11 inches you stretched it (see pictures) just tack it in and check it out before welding it permanently. Once everything is welded strongly and secure you should be all stretched as far as the chassis of the car goes. Once again, make sure its level make sure its even make sure its strong and make sure its right. If not you'll do a Herby the love bug impression. NOT GOOD. Now you need to stretch all the hoses etc that wouldn't make the stretch and create a sub frame so you can cut the roof.......
Now that your car stretched and back to one piece again you have to construct and install an additional sub frame to add support and rigidly to your car. You need to do this BEFORE you cut off the roof. the Fiero has a uni-body chassis, which means that every part of the car, including the roof supports the rest. If you cut the roof off without additional strength added before you cut you'll be welding on a flexible chassis which will surely not come out right. The actual frame will be constructed our of thick wall 1x3" steel. Click here for the complete text
Cutting the roof is not that hard. You will probably want to use your "Saws all". You need to take the windshield and rear glass if you haven't already. Once you do that just cut across the fire wall where the rear glass was. just follow the line the firewall makes around the side of the body on both sides. Click here for the complete text
If you look at the Fiero/Lamborghini overlay at the top of the page you see one of the largest discrepancies in the body line is at the front (besides the roof which we have already cut off). to fix this you'll have to do a few things. for one you'll have to take out A LOT of sheet metal from around the Fiero body (you'll also have to remount the radiator). Click here for the complete text
Now that you have some room to get to the radiator you can remount it. You will need to take it off the car as it sits and cut the ends of the frame back. Once you do this, you want to insert heavy metal plates inside the ends of the chassis. Weld them in so you have a strong firm base in which to hold your radiator and hold up incase of a wreck (heaven forbid). The bracket can be made a number of ways but is basically two thick pieces of flat coming straight down from your chassis with a tubular frame rectangle welded on the bottom of that. Your radiator sits in this. It lays at a slight angle to allow for the clearance of the body and give you a little bit of room for a front trunk.
We are rigging up a ram air system to direct as much air as possible through our radiator to try to keep the temp down. It seems to suck air really well as it is so I don't think we will have a problem but, if you decide to go with a high horse power motor, you might want to consider mounting two radiators in the rear to insure that you don't have a problem with overheating. Now we are ready to complete our side and dash support thus completing our chassis sub frame. From there all we need is a roll cage and we'll be on our way to mount.
Now that we have a radiator that will fit under the front hood of our body we need to strengthen our chassis by adding 1x3 (or 2.5) or similar steel around it. A you can see by the pictures we start by constructing a piece that fits around the curve to act as our dash support. Click here for the complete text
All of the side support in the world will not protect you if you happen to roll (heaven forbid) to protect you in case of such an incident and to give your body the strength it needs that fiberglass itself cannot give you will need to make a roll cage. The roll cage also is a wonderful aid in mounting as well as giving you the necessary support for hinges, latches etc. Click here for the complete text
With our strong streamline chassis done (minus a roll cage etc) we can begin to test fit. you probably have already done this before, after you stripped all the sheet and began the tubing to check measurements etc but if so or not you need to now. we are going to set the body on the chassis and mount it temporarily with bolt/screws. before you do this be sure you have trimmed off the rear "horns "at an angle so they don't get in the way. Click here for the complete text
These are the rims Nathan has picked out for the car. This is Nathan's windshield.
Many thanks to Nathan Galloway for his contribution to the contents of this page.