Author Topic: 70s & 80s Late model tech  (Read 6799 times)

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thirdgearspeedshop

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70s & 80s Late model tech
« on: February 26, 2019, 09:35:06 AM »
Hey guys, I'm researching dirt late models from the 70s and 80s (Camaros, bubble fenders, big spoilers) and I was wondering about the engine tech. did they run dry sump oil systems? electric fuel pumps? water reserve tanks? I'm looking into a pretty detailed build. any info is appreciated. Thanks

Brian Conn

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Re: 70s & 80s Late model tech
« Reply #1 on: February 26, 2019, 09:33:45 PM »
....there was a whole lot of changes from 1970 thru 1989, if you could narrow it down to ,say a few years, that would help...me at least.
  As far as what questions you asked, here's what I can tell you...
  I can tell you for a fact that in 1978 there was dry sumps showing up in dirt Late Models...seen it myself.
   Electrical fuel pumps , for the most part, where not allowed...too much of a safety issue with them still pumping fuel in the event of a fire.
  Water reserve tanks or expansion tanks could be found...some cars had them, others not....something more apt to be found on a pavement Late Model.
 
  Another detail item....in 1979 you could order a roller dirt Late Model chassis from Clayton Peterson Racing Products  Grand Island, Neb. with a manual rack and pinion steering set up.  It was between the 1978 and 1979 racing season that a lot of drivers converted there front suspension from the coil spring/weight jack set up to the coil over shock set up....around here at least.
 
                                         
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thirdgearspeedshop

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Re: 70s & 80s Late model tech
« Reply #2 on: February 27, 2019, 08:44:30 AM »
Thanks Brian,

To narrow it down, here are a couple of pics I'm looking for technical details on. I'm probably around 9 or 10 in the pic which would be around 1983.

 

john2

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Re: 70s & 80s Late model tech
« Reply #3 on: February 27, 2019, 11:59:04 AM »
Great pictures.
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Brian Conn

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Re: 70s & 80s Late model tech
« Reply #4 on: February 27, 2019, 11:03:50 PM »
I'm going to back date those pictures a couple of years from 1983.....
  By 1983 , particularly with the N.D.R.A , the bodies where pretty much non stock appearing wedges as opposed to what you have pictured...judging by what you have pictured, I would place them closer to 1979.
  Other reasons I am going with that time frame.....
 The wheels....both cars are shown with steel wheels.
 Both cars show a combination of factory sheet metal and fiberglass body parts.  Rear deck spoiler would have been around 12" give or take a couple of inches.
  As far as the technical aspects go , both of these cars display pretty much the norm for the late 70's ...particularly the 00 Freddy Smith ride.
  There is a variety of different set ups that could have been used.....the front set up could be either of the two that I described in my previous post...the rear more than likely was a leaf spring set up...a lot of the trick set ups for the rear ends would not come into play for a couple of more years i.e 4 links, Z links,etc. although the leaf spring on the Left /coil spring right rear could have been around then, Lefturns75 knows more about that particular set up than I do.   

  Engines could have went either way, dry sump or wet sump depending on $$$ available.
  I did see a few automatic transmissions in Late Models that year....a modified Chevy Power Glide for circle track racing.
  Are there any other areas you want to delve into?
« Last Edit: October 02, 2021, 08:12:43 PM by Brian Conn »
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gator

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Re: 70s & 80s Late model tech
« Reply #5 on: February 28, 2019, 06:41:40 AM »
Freddy Smith and Dennis Williams are both still around, you might want to contact them. Dennis is still racing in a vintage series and I think he is on Facebook.
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thirdgearspeedshop

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Re: 70s & 80s Late model tech
« Reply #6 on: February 28, 2019, 09:47:22 AM »
Thanks for the info guys. I was born in 73. I'm not sure how old I was in this pic.

I mainly wanted to get the engine details and suspension details correct for this era, or a little later (81, 82). I will be using an AMT NASCAR donor kit/engine so I need to back date it/modify it severely from the 90s.

Lefturns75

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Re: 70s & 80s Late model tech
« Reply #7 on: February 28, 2019, 12:20:06 PM »
Third, I am gonna agree with Brian here.  Those cars are not 80's equipment and look to be the early NDRA cars of 78.  Since you posted pics of Freddy Smith, here is a short time line in photos.  First is Freddy in 78 in what I think is a Barry Wright Car.

Next is Freddy in 79-80----

And then in 83---


If you want to do one from 81 on, look over David Bogards thread on the Larry Phillips build and that will get you the look.  Since you are using a nascar stocker chassis as a donor, that would be a good place to look for tips.  Other option----start with a pile of evergreen and a pile of photos and some time. 

thirdgearspeedshop

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Re: 70s & 80s Late model tech
« Reply #8 on: February 28, 2019, 01:30:15 PM »
Thanks Leftturns

Very helpful info.

Brian Conn

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Re: 70s & 80s Late model tech
« Reply #9 on: February 28, 2019, 09:46:57 PM »
........................I mainly wanted to get the engine details and suspension details correct for this era, or a little later (81, 82). I will be using an AMT NASCAR donor kit/engine so I need to back date it/modify it severely from the 90s.
  Narrowing down the years helps us to help you...which is all good :)
  The NASCAR donor kit will yield quite a lot.....
  It seems like you are wanting to build something from '78 thru '82 which will yield you the most possibilities as there was quite a bit of radical change with in those 5 years.
  Engine details....keeping in mind a NASCAR donor kit, I recommend a MOROSO air cleaner and Holley 4150 Series type carb.  Keep in mind what I said about the sump system..it can be either dry or wet.  Get a set of oil breathers and you will be set.  If you desire, a prewired distributor will enhance it.
  Suspension...again its what you desire....front and rear...ditch the NASCAR rear suspension and find a quick change and some leafs unless you build something closer to '82 in which 4 links where quickly becoming the hot set up.
  Up front, you could run the NASCAR set up which would date it closer to '78 unless you ditch the weight jacks and coil springs and go with a coil over set up which would have started to show up more in '79 and later.  Keep in mind what I said about manual rack and pinions being used in 1979.
  Steel wheels , as pictured til about '80-'81 then Aluminum wheels.  There where Aluminum wheels before 1980...they would look like the wheels on the Starsky & Hutch Ford Gran Torino for reference.
  Chassis seemed to change virtually overnight.  For something from '78 -'79 you could take the front frame stub from any 70's Camaro/Firebird and attach it to the NASCAR donor frame/chassis.  In 1981 Dillon introduced the first offset frame/chassis/cage for asphalt racing...the Mark II.... and it was very soon after that this design made its way into the dirt ranks.  You could convert the NASCAR donor to an offset with a little work.
  Don't shy away from the Gator bodies.....he's raced the dirt himself and his bodies are some of the best dirt bodies that I have seen.....I have a few myself and look forward to when I can get started on using one for a dirt build.         
« Last Edit: April 14, 2022, 04:49:15 PM by Brian Conn »
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thirdgearspeedshop

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Re: 70s & 80s Late model tech
« Reply #10 on: March 01, 2019, 07:36:51 AM »
Brian, Thanks for your knowledge. You have provided a wealth of info. The research is a big part of the enjoyment for me. I have attached a few photos of the best reference I have found so far on the web for this type of build. Perhaps it will keep the conversation going.

     

Brian Conn

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Re: 70s & 80s Late model tech
« Reply #11 on: March 01, 2019, 09:44:24 PM »
Brian, Thanks for your knowledge. You have provided a wealth of info. The research is a big part of the enjoyment for me. I have attached a few photos of the best reference I have found so far on the web for this type of build. Perhaps it will keep the conversation going.
....The pictures that you attached show a lot of detail, so much so that I saved them to my computer.
  The decade of 1975 thru 1985 is my absolute favorite as far as dirt Late Models go.....there was just so much evolution happening from year to year, sometimes even within the season itself.
  I too hope that this spurs some more conversation and pictures.
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thirdgearspeedshop

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Re: 70s & 80s Late model tech
« Reply #12 on: March 04, 2019, 09:41:28 AM »
So far the big picture items I have are (circa 79-80 give or take a year. it's a generic model not a replica):

Cooling system:
standard fan with safety shroud, catch can, no expansion tank. standard rubber hose? braided hose?

Induction:
Holley 4150 carb, moroso air cleaner

Fuel system:
mechanical pump. hard line? braided line?

Oil System:
Wet sump pan, no wet sump system, oil breathers on the drivers side valve covers

Electrical system:
standard distributor, accell coil

Exhaust:
crossover headers exiting on passenger side

Trans:
Use the trans from the AMT NASCAR kit? GM powerglide?

Front suspension:
scratch built coil overs and rack and pinon steering? Use the set up from the NACCAR kit?

Rear suspension:
Winters style quick change, leaf springs, shocks, Do I need a lubrication system? or is that too high tech for the era?
 
Wheels/tires:
Wide dirt tread Hoosiers with wide 5 wheels


Brian Conn

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Re: 70s & 80s Late model tech
« Reply #13 on: March 04, 2019, 11:44:43 PM »
So far the big picture items I have are (circa 79-80 give or take a year. it's a generic model not a replica):

Cooling system:
standard fan with safety shroud, catch can, no expansion tank. standard rubber hose? braided hose?
Either type of hose will work...if you use the rubber hose try and show double hose clamps at either end.

Induction:
Holley 4150 carb, moroso air cleaner

Fuel system:
mechanical pump. hard line? braided line?
either one will work

Oil System:
Wet sump pan, no wet sump system, oil breathers on the drivers side valve covers

Electrical system:
standard distributor, accell coil

Exhaust:
crossover headers exiting on passenger side

Trans:
Use the trans from the AMT NASCAR kit? GM powerglide?
Either one would work...you will have to plumb and run a tranny cooler with the glide                       

Front suspension:
scratch built coil overs and rack and pinon steering? Use the set up from the NACCAR kit?
       that all depends on how elaborate you want to be as either would work...the NASCAR set up is pretty simple whereas the coil overs and rack require a small bit of work           

Rear suspension:
Winters style quick change, leaf springs, shocks, Do I need a lubrication system? or is that too high tech for the era?
Just run a breather out of the rear end....looks like the oil breather on a valve cover...can be attached directly to the top of the center section or have the breather attached to a hose that is mounted on a portion of the roll cage, behind the driver,that is above the the rear fire wall        
 
Wheels/tires:
Wide dirt tread Hoosiers with wide 5 wheels
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thirdgearspeedshop

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Re: 70s & 80s Late model tech
« Reply #14 on: March 05, 2019, 06:39:37 AM »
Thanks for taking the time to answer my questions Brian! Hugely appreciated.