Questions regarding my 1978 Avanti

[Mike Hill]

Hi there.

I have just brought into New Zealand, from California, a 1978 Avanti II. Now I have all these questions which I'm hoping the wealth of experience out there will solve.

1/ Is there available a diagram of what all the controls/switches are for? There are several switches under the dashboard which I have no idea what they are for:

Large Rotary switch nearest drivers door

Three toggle switches next to that, one in a red plastic two others

Another toggle to the right of the steering wheel and further over another rotary switch.

2/Replacement A/C compressors?

3/It has a Nardi wheel. What does the steering wheel centre look like?

4/I'm looking at fitting a set of extractors (headers) It looks very tight. Any options there?

5/It's running the original 350/Quadrajet. Advice needed to replace the QJ & manifold?? I was looking at a Edelbrock Performer 2701 and 600 Holley.

Thats probably enough questions for now.

Glad this forum is operating,

Cheers

Mike

[Gunslinger]

Welcome! Great questions...hopefully we can help you with them.

1) I don't know if there's a schematic for the accessory switches as Avanti Motors made numerous changes during production. The large rotary switch under the dash of my '70 is for the rear window defogger blower. Whether that's the same for yours you'll have to check. The others I can't say...they could be additions by a previous owners. They could be for driving lights or something else. You may have to simply trace down the wires and see where they go.

2) a/c compressors. Most today replace the big GM compressor with a Sanden type unit, but that might require some bracket fabrications and new a/c hoses. You can always get another GM compressor that can drop in.

3) If I'm not mistaken, a Nardi has a stylized arrow in the center of the wheel. Arrow is not an accurate description but it's the closest I can describe it.

4) I don't believe Avanti specific headers are available but block hugger headers will work, though some designs might interfere with the steering mechanism on the left side. It depends on whether the two center pipes are inside or outside the outer pipes. I have Sanderson headers on my '70 and there were no clearance issues. As I said...some have said they had clearance issues but I don't know with what brands that happened with.

5) The Edelbrock Performer 2701 is an excellent intake and it's made specifically for a square-bore carburetor rather than the 2101 Performer which fits both a square- and spread-bore carb. The 2701 posts better horsepower and torque numbers than the 2101, which is a very good intake as it is. The Holley will do you fine but I'm partial to Edelbrock carburetors...just a personal preference. The 2701 intake is somewhat taller than stock so hood clearance may be an issue, but a drop-base air cleaner can remedy that.

To be honest...while the change in intake, carb and adding headers will make an improvement in performance, don't expect the car to turn into a rocket just from those changes. You'll likely find better starting, takeoff and overall drivability compared to the stock setup which has a lot of miles most likely. To really make a performance improvement you need cylinder head work and a new camshaft to wake it up. It all depends on what you're looking for. I would suggest to first decide what you want out of the engine (and car) performance-wise and make a plan to accomplish that. Once you decide what you want to achieve, then go ahead. A collection of parts...no matter how expensive or high quality...not matched together won't perform as well as parts that are matched towards a specific purpose.

Best of luck and hope to see you participate here often and keep us advised how things go with your car.

[warren55]

I tried to upload a picture of my Nardi wheel, but this site isn't picture friendly. 217 bytes just isn't enough! Anyway, try this:

https://www.facebook.com/photo.php?fbid=510403348979825&set=a.100843153269182.1849.100000304943197&type=3&theater

As for the switches, I think Gunslinger is right. I have several that I'm unsure of. I'm sure one was fog lights and one was a power antenna, the others, ? All have been bypassed at some point on mine.

[Gunslinger]

Mike...

What you can do to possibly identify those switches is to obtain a copy of the car's build sheet from Nostalgic Motors. It will specify how the car was originally equipped from the factory...what options, etc. That can tell you if those switches were originally there or were added later by a subsequent owner.

The build sheet runs something like $25-$30 and is well worth it for the information it gives.

[mfg]

My '83 came with a Nardi wheel with a center horn button exactly like the one in 'Warren55's' picture.

[Mike Hill]

Great info guys.

The interior of your Avanti looks very smart Warren. I have no horn button at all. I do have some Avanti logo roundels that i purchased from Studebaker Intl. and am thinking of mounting one of those. I should be able to find a Nardi button and replace the centre. I 'm aiming to use the other roundels to go in the magnum 500 wheel centres.

I'll endeavour to post a picture of the underdash area with the switches. After tightening them checking connections one is the electric door locks. The others are still a mystery.

I do have a build sheet which does indicate the door locks and electric antennae.

Did AMC put out a handbook/owners guide with the car?

Thanks Gunslinger for your info on the intake side. The original QJ carb is well past it. The 2701 and 600 were the suggestions from a mechanic who is our local V8 and SBC expert. All I'm looking at doing is the fundamentals. Good intake, effective carb, recurved HEi dizzy and some good headers. I don't really have the budget to be doing the heads and cam at this stage. RQB2701 needs a major repaint:-)

I don't know if we have Sanderson headers over here. Might have to check it out in the big smoke. Our little town 15000 popn doesn't run to any speed shops

Talking about paint. The original red was a "Damson Plum" Does anyone know if the car has a paint code somewhere or what manufacturer uses the colour??

This forum is a treasure

Cheers Mike

[lschuc]

Warren, not sure how you were trying to upload the picture of your steering wheel. I copied your photo from the link you gave, then I edited your post and added the picture. One think I notice is that Facebook must have reduced your photo to 66kb. Maybe that made a difference?

Lew

[Paul K.]

Once again, Bruce is on it. But the horn button with the arrow is for a MOMO wheel which I have seen some Avantis have during the Blake and early Kelly era cars.

Your Altman era Avanti used the standard Nardi horn button with no Avanti logo at least in the years prior to 1980 from what I have researched. (Photo )

Regarding headers, I have heard the stock "Ram Horn" Chevy exhaust manifolds breathed pretty good and are OK as is. But if you want headers, I have heard of Sandersons that were mentioned and another brand for tight applications like our Avantis. They go by the brand name "Block Huggers".

[Gunslinger]

Thanks for the correction on the steering wheel button...Avanti Motors did use a Momo wheel and I mixed them up.

Mike...if your build sheet doesn't give a paint code, look at the backside of the glove box mirror...there should be a sticker with the paint name and code added by the factory. Sometimes it might be on the underside of of the vanity tray.

Avanti Motors was pretty basic as far as owners manuals. They issued one in the early 1970's and simply ink stamped whatever model year was necessary after that on the cover and issued it with cars...at least through the Altman years. A more thorough manual was issued in the late '80s. Any updates and changes to the earlier manual were simply on typed sheets and attached. You can get reprints of that manual from Studebaker International.

[Mike Hill]

Hi guys. There has been some progress with the Avanti, mainly with fitting the new intake manifold, carb and fuel lines. The original distributor has also been replaced as it was due for retirement.

1/ I'm now after a replacement oil pressure sender unit for the SW gauge. Can someone give me the specs for that in regards to the ohms. There's nothing on the unit itself just 80 and 12v along with 53R. I presume the 80 is 0-80lbs. No idea about the 53 R bit. Is there a replacement kit number or an alternative? Stockists in USA? SW gauges over here are not common. I don't want to change the gauge. The plastic type shroud over the sender just disintegrated when I removed the unit.

2/ Is there a good quality paint stripper for removing the paint on the body that won't leave me with a molten fibreglass mess

Gunslinger, I did locate that paint sticker in the glove box, but alas the code was illegible. There's a fair bit of work before I think about paint.

Cheers

Mike

[WayneC]

Have a look at this Corvette forum thread:

http://forums.corvetteforum.com/c1-and-c2-corvettes/2813678-stripping-old-paint-from-fiberglass-corvette.html

In addition to recommendations on chemical strippers, there is a link to a video showing razor blade stripping,

which has lately become a common method.

A Google search returned these paint references:

http://www.expresspaint.com/automotivetouchup/pc/GM-Damson-Plum-Firemist-Metallic-21p16764.htm

http://paintref.com/cgi-bin/colorcodedisplay.cgi?style=print&color=Damson%20Plum%20Firemist&rows=50&sort=gmcode

Edited May 24, 2014 by WayneC

[Avanti83]

I looked at the link on removal with a razor blade and about fell off my chair. I don't know how bad his paint job was but my 74 had paint popping off in some areas but the majority was well enough adhered that by my calculations, I have over 150 razor blades and possibly as high as 80 hours in scraping my paint off.

I'd do it again because I have more time than money but don't go into the process thinking that the vette is the norm. You'll leave nicks but a good high build filler will take care of that.

I'll post a shot of the scraper that worked best for me if anyone wants to start this process.

Bob

[WayneC]

Bob, I'd be interested in seeing the scraper that worked best for you.

Here's another video on razor-stripping:

And having a professional soda-blast the surfaces to remove paint is yet another method.

Edited May 25, 2014 by WayneC

[CaffeineRacer]

A suggestion for headers. Many will run the factory corvette "rams horn" style exhaust manifolds. They have been shown time and time again to have performance equal to headers on street applications, can be had in 2-2.5in diameters, and will fit in tight spaces.

Here are some cheap replica ones a lot of people run (note these have brackets in the casting for alternator that may need to be cut off and also make them left/right specific). http://www.summitracing.com/parts/rnb-674-503/overview/

These are a slightly modified version. http://www.speedwaymotors.com/Tru-Ram-Small-Block-Chevy-Exhaust-Manifolds-Cast-Iron,3823.html

I'll be using a set of the cheapos on my new custom vortec 350 once it's done.

[Avanti83]

A suggestion for headers. Many will run the factory corvette "rams horn" style exhaust manifolds. They have been shown time and time again to have performance equal to headers on street applications, can be had in 2-2.5in diameters, and will fit in tight spaces.

Here are some cheap replica ones a lot of people run (note these have brackets in the casting for alternator that may need to be cut off and also make them left/right specific). http://www.summitracing.com/parts/rnb-674-503/overview/

These are a slightly modified version. http://www.speedwaymotors.com/Tru-Ram-Small-Block-Chevy-Exhaust-Manifolds-Cast-Iron,3823.html

I'll be using a set of the cheapos on my new custom vortec 350 once it's done.

I've used a set of those "Cheapy" 2.5 inch Ram manifolds on both my 355 SBC 83 Avanti and 383 SBC 74 Avanti. I just cut the brackets off and ground them smooth. $50/ea is about the going price at both Summit and Rock Auto. An original 2.5" set from 63-65 Vettes price will scare you. They were designed by GM to flow well on the HP engines of the time. If they only supply one side, don't worry when you cut off the bracket, they will fit either side. Just order two and get on with it.

Bob

[Avanti83]

Wayne

I used a Titan razor blade scraper

And a cheap plastic one for tight spaces

Bob

[Mike Hill]

Thanks Guys

That's some excellent info on paint removal. My painter is chasing up the supply of paint stripper for me. I've never used the razor method before. It looks scary, as I'd be worried about deep gouges. Why has this method become so popular? The paint info on Damson Plum is very helpful. Cheers.

Currently I'm going down the route of keeping the original 'ram's horns, as my budget is reasonably tight.

Did anyone have some info for a replacement oil pressure sender? Apart from Stewart Warner originals which are very rare here I haven't found an option yet Specs 0 - 80lbs 240ohms Single wire from top connector.

Many thanks

Mike

[Avanti83]

The scraping method is essentially cheap as long as you don't pay for labor. I'm not sure what you mean by "DEEP" gouges but a razor blade won't dig very deep into fiber glass if you pay attention.

Be careful about what stripper you use. Avanti's don't have a gel coat and anything that sinks into the class resin matrix could haunt you in future. IIWY, I'd contact Brad Bez "Bezhawk" on the SDC and ask for his recommendations. I think he's on here but don't recall his forum name. He is a quality restorer that has done some beautiful Avanti's and best of all, he's always willing to give advice based on his experience.

I'd also email S&W and ask for their recommendations on the sender. I know that 240 ohm is still available but don't know if it's compatible.

Good luck

Bob

[plwindish]

My '76 has the wood-tone Momo wheel, but has the Avanti logo in silver lettering on a black background on the horn button. It was that way when I got it 3 1/2 years ago.

A thought on new carb and intake manifold. Your '78 350 is probably as "smogged" and detuned as the 400 in my 76 was before I had it rebuilt. If funds allow, you might want to consider a rebuild or a new crate 350. My rebuild consisted of being bored 30 over, new pistons, roller cam, new Edelbrock polished aluminum intake and performer 650 carb, head work to clean up the passages, block hugger headers, new water and fuel pumps and appropriate "bling" for the motor. I could have gotten a new crate motor for what I put into the rebuild, but I wanted to keep the original motor in the car. The rebuilt motor dynoed at 365 hp and 460 torque before being put back in the car. The car has no power issues at all. It runs great and with the rebuilt 200R4 that was put in after the motor rebuild, it cruises great with decent mpg (21.5-22.5) if I keep my foot out of it.

[jeffdgale]

Hi All.. The paint is chipping and pealing like crazy all over my 74. The car seems to have a home paint job and I assume the prep was not very good. I have stated to experiment with different ways to remove the paint. Surprisingly a light touch with a heat gun and razor blade is very easy and pretty much everything comes off down to a gray finishing in which you can see but not feel the fiber stands. I assume this is the "raw fiberglass" but removal is so easy with this method it scares me. I am wondering if I am taking off too much. Is there a gelcoat that I want to try to preserve or am I fine to go down this gray fiberglass layer.

[Gunslinger]

I do not believe Avanti Motors applied gel coat to the cars...at least not during the Altman years. They used an acrylic lacquer which, as years went by, would crack and check. That may be what you're seeing on your car.

I would suggest when the existing paint is completely removed you apply a gel coat. It will make for a much better looking final finish. People don't believe my car is fiberglass as there's none of the "ripple" they associate with fiberglass. They think it's steel until they rap it with a knuckle.

[Mike Hill]

Hi there

Still haven't managed to track down an oil pressure sender unit. Most of the ones available her seem to be either 60lbs or 100lbs.

Can anyone tell me the colours that these items were in the original Avanti II as I've probably seen every colour imaginable??

Engine block?

Engine bay?

Fan shroud?

Fan blades?

Brake booster?

Did the Avanti II have any air cleaner decals? Other under bonnet oops hood decals?

Thanks for all the help to date. There's plenty of winter garage activities planned out!!

Cheers

Mike

[Gunslinger]

80 psi oil pressure sending unit...Stewart Warner 279A...available from Summit Racing.

Engine block...Chevy Orange.

Engine bay...body color.

Fan shroud...black.

Fan blades...red or orange (I think).

Brake booster...black or whatever color it came from the vendor...maybe natural, unpainted. By this time, many have taken on that nice, rusty patina.

Some of those might change year by year or by whatever finish the vendor supplied them in. 1978 was also the year GM started painting all their engines "Corporate Blue" so it depends on when Avanti Motors sourced the engine so it might be Chevy Orange or Corporate Blue. The fan blade color might be black as well...depends if they're GM supplied or another vendor.

Decals...someone else can better answer that. It may have had an "Avanti" decal on the air cleaner lid and the required emissions decals on the cowl but I can't say for sure.

Edited June 2, 2014 by Gunslinger

[Mike Hill]

Thanks Gunslinger.

The next procedure - I was hoping for the "low effort" option of doing the maximum of work without taking the motor out, but two leaking rear frost plugs (I think you guys call them core plugs) at the back of the block have led me to the motor out option. It'll probably be better in the long run as I can then check everything as well as the header replacement and complete engine clean and repaint.

My mechanic. I'm not a SBC expert...(I spent lots of years on Alfa twin cams and GTV6s before returning to my "Stude" roots so to speak. An Avanti II still counts!!) has said that he thinks we should replace the heads/cam as the current ones are "poor" Your thoughts guys?

Cheers

MIke

[Avanti83]

Mike

A thought on SBC's. They are about as straight forward as any engine you can work on. Not much to get into trouble with.

If you have a leaking plug it's time to get the engine out and replace all the plugs and add a gasket set. Nothing good comes from leaving the engine in and not doing a complete reseal.

If you like the way it runs then you are OK, but if want it to run like a good Avanti/SBC 400 should run, I'd look at the heads and cam.

I use Nasty Z28 to decode SBC parts. http://www.nastyz28.com/chevy-engine-code-stampings.php Find the numbers on your heads and look them up here. Another way to access them is to Google "SBC heads # (your heads)" and see what you find as far a compression ratio, valve size, etc.

The best way to find the correct cam for your use is to call/chat with Lunati or Comp Cams. Their tech folks are good and they can recommend what you need for your requirements. I don't have any experience directly with Edelbrock but a well respected company that I would think can give excellent recommendations on both heads and cam.

One thing I quit doing was just asking what cam works from the general public. To many variables or lack of experience. Either ask a local SBC expert or talk to the cam/head companies as there have been way to many advances in head/cam technology in the last few years.

On the plus side, Nothing wakes up an SBC like the correct heads and cam.

Setting in my pole barn is a half finished 74 with a 383 SBC backed with a T56 six-speed. It has a Lunati cam and the early big valve iron heads at 10:1 compression. In the little I've driven it, it will drive you back into the seat. It's like being back in the 60's only better.

Lastly, before you go any farther. Do a compression and leak down check on the engine before pulling it and then open up the bottom end and check bearing and rod clearances. If they are off there's no sense in throwing a couple of grand at a worn engine. If it's worn then you might consider a crate engine with the upgrades in place. Probably less expensive even in your neck of the world.

Good luck, a great running SBC is a very enjoyable ride. Bob

Edited June 20, 2014 by Avanti83