Not Quite A GT40: Fiberfab Avenger V8

Fiberfab Avenger

You may remember Fiberfab, if you’re old enough, from their dreamlike ads for their kit cars in the back of motoring magazines. Promising exotic sports car looks with only a little effort, I remember thinking how easy it looked. Boy, was I ever wrong. As a current kit car owner, although not a Fiberfab, making a bunch of component parts all come together to make a running car is a lot more difficult than it seemed, and many kits ended up incomplete. Despite being incomplete, this one has an interesting makeup that certainly intrigued me. It’s listed here on eBay and is located in Florissant, Missouri.

Fiberfab Avenger GT

Avengers were originally intended to be mounted on VW pans with the little flat four providing motivating power. This one, however, has been mounted on what is said to be a Kelmark GT chassis, with a mid-mounted Chevrolet V8 and a beefed-up Corvair transaxle in the rear. I was able to confirm the chassis as a Kelmark by looking online; it certainly looks like one to me. The Kelmark GT was another kit car, this one modeled after a Ferrari 246 Dino with, for trivia lovers, Chevrolet Vega doors. It could also be built with the VW engine, but many were built on this bespoke chassis. It does leave the engine very close to the passenger compartment, and I can’t help but wonder if the Kelmark’s driver compartment was further forward than the Avenger’s and if this could cause some awkward seating arrangements.

Fiberfab Avenger With Kelmark Chassis

The chassis seems to be solidly constructed, with only surface rust to be cleaned off before painting. I’m unclear about the front suspension on this car, but most of the Kelmarks I looked at online had VW-based front ends. The seller states the obvious that it’s a project, but also mentions specifically that lots of the controls aren’t finished. I hope anyone completing this car would consider some serious brakes; at around 2500 pounds completed, that 350 V8 can get you going pretty darned fast.

Fiberfab Avenger Kit Car

You can see in this side shot that it’s not exactly a perfect replica of a GT40, although the flavor is certainly there. That missing rear window is from an early Mustang, so it should be available. I’d have to paint it Gulf blue with an orange stripe and numbers; I know that’s very clichéd but those iconic GT40’s were a part of my childhood. I’d love to see this car finished properly—I’d certainly find it a spot in my garage! There are a lot of beautiful examples at to get ideas of what it could look like completed. So how would you finish this one?


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  1. Rick

    There’s a reason this thing has sat around unfinished all these years because it would take way too much work and $$$. Sure the finished product would likely be cool enough I guess, but . . .

    Like 1
    • Joanne Stevens

      oh hell with that id love to get that on the road and decked out if i had it!

      Like 1
  2. vince Habel

    I agree with Rick. put it back out in the field and let it die in peace.

  3. Woodie Man

    I always liked red.

    • Jamie Palmer Jamie Staff

      I love the Jamaican…always have done. Have pursued one several times, but $ and time never seemed to be right. Maybe someday…

    • Larry

      I prefer the tan model myself

      Like 1
  4. Dan Farrell

    If the transaxle is pre 1964 it could also be bad news the first time you went hard into a corner, if you ever did get it finished.

  5. Fred

    We bought a unfinished Avenger kit car thinking the po did all the hard work. We learned he did the easy stuff. The guy we sold it to was delusional as well.

  6. tom

    at first I thought they were neat,but ugly as sin. that bulbous rear end screws them up. and this one leaves little to be desired.

  7. Alan (Michigan)

    The Kelmark units were set up for the late model ’66+ Corvair transaxles. The shortcoming was that flipping the transaxle around meant applying power via the “coast” side of the ring and pinion gears, and they don’t like that a lot. Kelmark had a run of specially cut R&P gears made, with the proper direction of the meshing arcs. If this has one of those, it alone has a good chunk of value to people who have the Kelmark setups in Corvairs or other cars. Out of the ones made, IIRC, some were not heat treated correctly, and suffered short lives as a result. All is not lost, however. The materials were said to be good, it was just the treatment which was deficient. First thing a new owner should do with this one is to check and see which one it is, and then if the special one, have it tested for surface harness, perhaps even put through a heat-treat.

    The ad states that the transaxle was “built to hold up to the horsepower”. Likely that means installation of a 4-spyder (instead of factory 2) ring gear carrier. While definitely a good idea, it does not make the setup anywhere near bulletproof. Practical limits are in the vicinity of 300 – 350 hp. With a light car such as this, maybe 400. There are stronger options. What breaks the systems most often is a hard launch.

    The rear suspension looks to be mostly late model Corvair. Although there are no photos of it, quite possible that the front is also Corvair. There are plenty of options for disc brakes, front and rear for the late ‘Vairs.

    A lot of work needs to be done. If the seller’s reserve is $1 – 1.5K, then this should find a home. More than that….

    Like 1
    • James Wright

      That car is not an Avenger. It is a Fiberfab Valkyrie on a Fiberfab Valkyrie mid engine bespoke chassis. I have owned 3 Avengers, 1 Valkyrie and 1 Kelmark GT. My Kelmark mid engine system was designed to use an 1968 Olds 455 Toronado engine and trans. It was a beast of a car that liked to lift the front wheels when I stomped on it. The TH425 had it’s problems in that setup. Mainly that the trans pan hung very low and at the very tail end of the car. I dragged that pan every time the car lifted the nose. I had to make a skid plate just to keep it from destroying the trans. Almost all the Kelmark mid engine kits were setup with the Toronado trans. The Corvair trans was used in the Valkyrie with all the problems you stated and then some. The kit was designed by Crown engineering and was a piss poor substitute for the TH425 that was used in the Kelmark mid engine setup.

  8. Jesse Mortensen Jesse Staff

    Chuck F just sent in a link to another Avenger that’s listed on craigslist for $1,300. Find it over on the right hand side of this page under our new “reader finds” section!

  9. jim s

    i think this will sell for parts, the new owner taking what they want/need and then relisting the rest. if they are lucky they could have the parts they keep at no cost. it does look like half shafts on the rear and maybe VW front end as i think i see a tube in one photo of the dash. i too think it would be way too much time/money to try to finish. and i would not want to drive it! great find

  10. rogerowen

    I would absolutely love to take on this project! Sadly, wrong side of the ‘pond’ – so would cost too much to ship to ‘Blighty’!

  11. Sean

    Dug some of these off the net.. thought your readers might enjoy them. ;)

  12. Sean

    Fiberfab ad.

  13. Sean

    .. another Fiberfad ad.

  14. Sean

    .. and one more.

    • rogerowen

      What is amazing is that this body kit was actually designed to fit a donor Austin Healy, Triumph TR, MGA or VW – all of which would now probably command far more dosh than this sad looking Kit Car will achieve!

      BUT, there’s something very alluring about this design, even though full of all sorts of challenges!

      Apparently I could buy a nice house near to this car’s local for a whole lot cheaper than here in the UK – all very tempting! Sitting on my hands and not logging in to Ebay for a while – just in case!

      • Jamie Palmer Jamie Staff

        Actually, this one was designed for the VW pan, although there was another version of the body sold with it’s own frame and designed for a V8. The Jamaican was designed for the Healey/TR/MGA chassis.

        Like 1
  15. Dolphin Member

    Looking at a bunch ‘glass bodied homebuilts over the years, none of them actually fully built, has taught me respect for the designers and engineers who make real cars.

    With this car, apart from whether the transaxle would hold together or whether the brakes would work, my biggest worry would be whether that rear clip would fly off at anything over 40 MPH.

  16. Mark E

    I saw maybe half a dozen of these back in the day, all on VW pans with VW engines. Beautiful cars but can’t imagine what a headache it would be to graft in a V8, not to mention finishing this project. A lot would depend on if the builder actually knew what they were doing or just went off on a plan drew out on a bar napkin one night.

  17. Marc Lawrence – New pictures of the 2013 model will be posted here soon – lol

  18. Charles

    Where is the driver going to sit in this car? By the time one builds a firewall in the car, there will be no place for seats. Someone did not measure before they cut and welded.

    • rogerowen

      What firewall? I quite like the idea of a V8 lump ticking away in my left ear!

  19. Charles

    You could mount heat shields on the exhaust manifolds and use them for arm rests.

    Don’t get me wrong. I love the idea of a light weight mid engine car with a Chevy small block V8 for power. This car does not appear to have enough length to have room for the engine and a driver or passenger. Maybe a better choice for this car would be a GM Vortec V6?

    Or one could split the car in the middle and add a foot or so to the length.

  20. Charles

    I remember seeing a 65 or 66 Corvair coupe with a mid engine small block Chevy V8 once. This was in Florida in the late 60’s, or maybe 1970? Sorry, no pics. It was awesome. I got to ride in it for a couple of miles. The first thing the owner did to the car was install a HD sway bar in the rear to stabilize the trans axle. The car handled like it was on rails. They installed the engine like this car in front of the transaxle. They built a steel firewall behind the front seats and a steel door for an engine cover. The whole thing was insulated and finished off nicely. They integrated a roll cage into the design, which tied the car together and increased the rigidity over a stock Corvair body.The radiator was in the original engine bay in the rear with electric fans.

    • Alan (Michigan)

      Crown was the name of the company which made a kit for the mid-engine Corvair (CorvEight, or Corv8) conversion. Their setup bolted the bell housing to the front of the transmission, as in: Engine, Transmission, Differential, from front to rear. There are plenty of those running around, and more still being done. Mike Levine regularly races one in vintage events, and it is a really fast car: He runs a stroker small block, and has recently sourced a proper vintage transaxle which can better handle the torque.

      The Kelmark conversion kit was created in part because of a shortcoming in the Crown setup: Limited space for the driver. With the transaxle rotated so that the transmission was on the rear, nearly a foot of space could be gained for the driver and passenger.

      Like 1
  21. dougm

    Had one of these bodys sitting outside my one bay converted corn crib shop years ago. A good friend talked me into storing it in hopes of “us” putting it together. Problem was his daily driver, Fiat 124 Spider needed constant work ,duh, and he never quite had time or funds to see it thru! I can’t remember what happened with it but I do have fond memories of walking out to the shop and feeling “cool” that I had an “exotic” parked w/the boring Veedubs there for work.

  22. Henrique

    Maybe you know that in Brasil (Sao Paulo) someone tried to produce the Avenger under the name “Shark” by 1970. This one told motor magazines it was an original Project from his offices (a company named Trivelatto). When the newsmen found out it was just the Avenger, it was a shame. The Project failed out and there were made only 20 or less cars, that are very rare today.

    Like 1
  23. Ray

    Hey Henrique,

    Thanks for sharing that bit of GT-12 Avenger trivia with us. I am an avid fan of this humble little home-built. I remember seeing the image of the advertisement you submitted, but didn’t have the complete back story on it. Very cool. I will post some pics of the Avenger I’ve been driving for years. I believe it is one of the very few units on the road. Take care…Ray

  24. Ray

    Henrique, here’s the one I drive.

    Like 1
  25. Brian

    Of all the kit cars to come out of the ’60s and ’70s, the F.F. Avenger would be my only choice (although the dunebuggy bodies are cool, the open body makes them so limited for daily use)! It amazes me how many of these turn up for sale fairly regularly, for cheap money, having never been completed in there 40-50 year lives. Most people who have actually bought one and finished it will tell you that the bodies are complicated and weakly reinforced, especially the doors. But what worthwhile is ever easy?

    I have to agree with some of the posters above; to take on a kit car designed to mount to a VW pan and to turn it into a V8 monster would be a task – not for the weak of heart, wallet, brain, and talent! But to me, there is alot of appeal in just owning a VW powered example. There are no shortage of go-fast goodies available for the flat four VW engine, and for not alot of money. Their are still plently of battered Bug bodies around to rob the pan from if needed and for nearly nothing, so what the heck! Even if your finished product isn’t perfect, your still going to have the most interesting car on the road to commute to work in! No way are you NOT going to get a ton of thumbs up, smiles, honk and waves driving one down the road – in fact, your going to get more of them than embarrassing moments when the 20-somethings want to race you in their Mustangs! I’m with the guy above, there is always room for one of these in my garage, too – even if I have to suspend that light fiberglass body from the rafters waiting for the extra cash needed to get to work on it!

  26. Ray

    Hey Brian,

    Nice comments. I own several types of vehicles, including a 1963 SS Chevrolet (rag top) Impala, 1970 1/2 Z-28 Camaro, 1954 V.W. Beetle and a 1950 Tempo Matador. Although, all have unique and exciting driving capabilities, this little Avenger takes you back in time and handles like a true track car. I chose to use a stroker 2300cc aircooled V.W. powerplant which is neatly tucked into the aft compartment. It is set up with dual 44 Webers and produces a humble 150hp with room for more stallions if desired. The sturdy, one piece fiberglass 40+ year old body is mounted to a sourced, 1971 V.W. I.R.S. pan, which contrary to a lot of commentors beliefs, has all of the engineering feats already built into it. Because of the low center of gravity, and the addition of front and rear sway bars, this unit sounds, feels and handles like an exotic sports car. Even the Porsche and Ferrari crowd can’t help contain their curiosity and admiration. This is an old school build that has survived the gauntlet of the hack saw. Continue to innovate not duplicate…Ray

    Like 1
  27. Edward Glamuzina

    I to own a Avenger. It sits on a Karmen Ghia pan,has 4 wheel disc brakes from a 356 Porsche,early Empi magnesium wheels,sway bars front and rear,Koni shocks,Wright rack and pinion and it’s powered by a VW 1918 with dual Weber 48’s. The cars roof is well below my waist and the car weighs less than 1100 lbs..The low center of gravity and low weight combine to make an excellent handling car as well as being extremely quick. The car is a lot of fun to drive. It is a time capsule as it was built around 1967-68. It is going to need paint soon but it still turns heads. Whenever I drive it I find myself saying many times a day,”No, it’s not for sale”.

    Like 1
    • jpc

      Any pictures you can share? I also have an Avenger but on a bug chassis. Was interested in seeing how the Ghia chassis centers up the wheels in the wheelwells. The bug one is the wrong length and you can see it in many builds where the front wheel is behind the location it should be in the wheel well.

      • James Wright

        . A VW Karmann Ghia chassis is 240 cm or 94.5 inches. A VW beetle has the exact same chassis dimensions. In fact a VW Beetle body can be directly swapped onto a Karmann Ghia chassis. VW would never have built a special chassis for the Ghia, interchangeability was one of VWs secrets to success. They saved a lot of money by cars sharing the same chassis and they still use that method. I have owned two Avengers and the wheels were positioned correctly on both. Mine were both on VW Beetle chassis. Due to the unusual trailing arm design used on VWs front suspension. The lower a car sits the further forward the wheel moves. A car that has the wheels looking too far to the rear was probably sitting very high in front. Lowering the car rotates the trailing arm forward, and brings the wheel into the correct position.

        Like 1

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