Heater and fuel tank options

Afternoon,

We're getting close to adding in the firewall, fuel tank and heater. Looking through our manuals, pretty straight forward, however we've realized the doner car the heater and fuel tank came out of is a 89 mustang LX, where they called for 74 - 78 mustang II doner car, gas tank out of a 76 - 82 chevette - that I have sourced and can get pretty easy, the heater is looking like a problem. Now, I haven't tried to fit the 89 mustang one but suspect it won't fit and controls won't work....do you guys have any advice on what you used? I looked through the gallery and it seems there's a mix of heater options.

We are going to check dimensions of the 89 mustang fuel tank vs chevette and see if it will fit with the correct filler hook up - driver side which it has.

We arn't going with A/C - its convertible!

For the gas tank, the general consensus is that you have three options

-The chevette tank, which is very small for the engine capacity and will only give you a max range of ~140 miles, but is cost efficient. I have it in mine. Works fine for a weekend car but i'm looking to upgrade

-Find one of the super rare classic roadsters-made optional large tanks

-get one custom made out of aluminum

For the heater

-74 ford mustang units can be found used on ebay, but I would recommend replacing the heater core before installation. Also note that they are huge and a pain to fit and remove. Be careful not to wire the heater motor backwards or your defroster won't be very efficient.

-if you have some coin handy, I would look at units from vintage air. Much smaller and probably would afford more room in the passenger footwell.

I, like Hotrod, have chosen the "build it yourself" option with regard to tanks. We both have bumped up capacity to 16 gallons and installed internal baffling so as to minimize the bouncing fuel gauge needle affect as you draw down on the tank. Hotrods tank is configured for fuel injection, mine for a carburetor. Both are made from aluminum. Hotrod welded his together (scary talented) while I am going the solid rivet and PPG Proseal method (same as I used when I built the wing tanks in my plane). Both designs exploit the unused space between the top of the OEM tanks and the bottom of the trunk floor, sort of a two level square wedding cake .

I second David's recommendation for an aftermarket AC/heat unit.  The street rod industry has done wonders to stimulate the design of good units.

Vintage Air is probably the best known and they have good stuff.  There are other manufacturers, but VA will have everything you need for a custom installation. They have stand alone heater units also.  I have a VA unit for my car.

The MII and Chevette stuff is getting pretty old and repair parts availability is iffy and most likely won't get any better.  

Somewhere I have the original MII heater that was in my car.  It didn't work and had been disconnected.  I don't have the controls, but if I can find it, you are welcome to it for the shipping.  I don't recommend that route though.  The hoses go thorough the firewall (on mine at least) in the center of the firewall.  To me, that's not the best location.

Remember that these cars were intended to be built using the "donor car" concept to save the builder money.  The parts used were not always picked because they were the best choice, but because they were commonly and cheaply available in the 80's. Not so much now.  For a new build, I feel you would be better off going forward if you picked parts that are easily sourced now even if that means going outside the manual.

As far as the gas tank goes, David is correct in that range will be limited with a V8 and the Chevette tank.  Also, the original GM senders or getting difficult to find.  Mine didn't work when I bought the car, but I was able to repair it.

The tanks are available new from the aftermarket, but I couldn't locate the sender.  There is a universal VDO sender that has the same resistance as the GM sender.  This could be adapted to the Chevette tank if you have the gauge and just need a sender.  Also, all GM fuel senders of that time period had the same resistance as far as I know, so you might be able to find one that could be modified to work with the Chevette tank.

If you still have to buy instruments, then I would skip the GM sender and just get a readily available aftermarket sender for what ever gauge you get and make that work with your tank.

Somewhere on this site, there is a drawing of the original Classic Roadsters oversize tank.  I would recommend getting a new tank built.  The only drawback to the CR tank is that it hangs down and could make exhaust routing difficult.  

DrJ and I made use of unused space between the frame rails and were able to keep the tank fairly shallow.  You are limited to about 16 gallons that way, though.

BTW - I looked at ready made fuel cells and poly marine tanks.  I also looked at universal tanks made for hot rods, but I never found one that fit and had a decent capacity.  Your luck may be better.

I checked, all the instruments I have are the original VDO gauges, still in their shipping boxes from Classic Roasters, so I think I'm good on that front. Just need to source the sending unit. Thanks Hotrod for the feedback, always appreciated.

I'll throw in my .02 cents and agree with all said about the after market heater. My unfinished kit came with the MII heater/AC unit complete.
I also thought "who needs AC in a convertible ?"
That - for sure - was a big mistake. Last time we drove to the Bay Area it was miserable. The added weight and HP loss would not be noticeable. Sure, more $ but I believe it's worth it even if you live in a mild climate area. Where do you plan to drive and what time of year? Just my opinion based on 15 years of driving it. Still fun, but would be more so with AC.
YMMV
Jerry
P.S. I have the 19 gallon tank and love it.

Hotrod,
What specific VA unit/model did you use? My heater core started leaking, pulled the whole unit out and the plastic is showing it's age...old and brittle. I'd rather upgrade than replace with an old used MII unit.
Charles

Charles, I am using the Gen II heat, cool and defrost number 61005-VUZ-A.  It's on this page:

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It is a very large unit and just barely fits my car, but I have made many mods to the firewall area.  This unit was recommended by a guy I know that builds hot rods for a living.  It is actually large enough to heat and cool a large 1940's sedan, but I figured that with the convertible top, the Sebring would need plenty of extra capacity.  I was looking at the more expensive Gen IV system, but he told me I didn't need to spend the extra money, since he had pretty much always used the Gen II's with very good results.

Vintage Air has drawings on their webpage showing the dimensions of all their universal units.  I built a simple cardboard box with packing tape to the rough size of the unit I'm using to see if it would fit.  Don't forget that the hoses need some room to bend coming out of the unit.

Hotrod,
I was looking at VA website, among others getting ideas. Thanks for the mock up idea.

Charles

MC247, which part of Ontario do you call home? We're in Georgetown, west of Brampton. We'll be taking our "MX" out of hiding in a couple of weeks.
Regards,
JimboQuick