Mopar 8 3/4 question
 

I do not have a stock or super stock car but my son and I run in the F.A.S.T. series ( factory appearing stock tire ) with a 1971 Plymouth Duster. We have to run factory casting number correct intake manifold, exhaust manifolds and heads with full exhaust and polyglas tires. The car also has to have a stock appearing interior. The motor is a large small block that makes 480 HP. So far we have run a best of 10.79 @ 123.87mph.

We have picked the brains of some local upstate NY stock eliminator racers and they have helped us setup the stock appearing suspension The best 60 foot so far is an 1.54.

Over the winter we are looking to change the rear end from a stock housing, steel spool and 35 spline axles to an aluminum spool, aluminum housing, lightened gears,and gun drilled axles.
Has anyone done this to see what the real world gain would be?

Thanks
Gene

Re: Mopar 8 3/4 question
 

Sounds cool I would also add a 904 & Aluminum driveshaft. Keep us posted that's how we all go faster.

Re: Mopar 8 3/4 question
 

WOW! That is flat amazing! Beautiful car too.
Is there anywhere on the net that we can read more about the car?

Keep us posted on your updates.

Re: Mopar 8 3/4 question
 

Yes there is a site to check (F.A.S.T, Factory , Appearing, Stock Tire) ! There is a SS/AH racer that has a car like this !......It's a lot of fun from what he tells me ! There's a picture if the Demon on there web site cover ! Type in the above for the site !.........John

Re: Mopar 8 3/4 question
 

If you don't have a Pro Trans, spend your money there. The housing ain't worth much if anything and doesn't fit well. That is a pretty hefty dollar to do all that stuff. Aluminum shaft is not too expensive. I assume you got Cal Trac's already. How about converters? I might have some stuff. Jeff Teuton jefft@southlanddodge.com

Re: Mopar 8 3/4 question
 

TOO COOL :

http://classracer.com/classforum/att...2&d=1385654404

Detail:
http://classracer.com/classforum/att...1&d=1385654404

Re: Mopar 8 3/4 question
 

The rules are pretty strict for the suspension. Did your car come with 70 series tires or was there a model with a 60 series tire ? How loose of a converter do you have ? Trying to launch one of these cars must be tricky.

Rear Suspension rules from the FAST rule book.

Rear Suspension: Traction devices are limited to hop-stop bars for the upper control arms on coil-spring cars. Pinion snubbers and clamping of springs are allowed on leaf-spring cars. No slapper bars or ladder bars of any kind are allowed unless originally equipped at the factory. Factory documentation will be required to prove authenticity for any car equipped with bolt-on traction devices. No dealer-installed traction devices allowed. After-market upper and lower control arms for coil spring cars are not allowed. Raising or lowering of the rear end is not allowed.

Re: Mopar 8 3/4 question
 

The transmission is a lightened, rollerized 904 but not a protrans. The converter is a custom Ultimate converter designed by Lenny. After a couple of updates it is spot on. The converter is on the tight side because the G70-14's do not hook like slicks.

Jeff, we are trying to take 150 pounds out of the car for next year. We were wondering if reducing the rotating weight would gain us more than just the weight gain itself.

The web site is www.fastraces.org

Re: Mopar 8 3/4 question
 

I understand the housing doesn't fit well. We can't run one so I only know what I have been told. I don't know if they are in the book still, but there are some around. Could you just have your 35's drilled & lightened & save a little. Also are you running a stock housing? They bend unless well supported or braced? If the axles go in easy, it's straight. I always found the right side would bend forward. Lightweight trans worth at least a tenth over the roller trans. Pricey though. What ratio in the trans? Might be something there. With the lightweight stuff and straight cut geats ratios range from 2.00 to about 2.80 first. Be easy to calm that thing down for those little tires. How about front shocks? I got some used Strange Double Adjustable from our SS car. Good shape, replaced all of them with Santuffs. Or what do they allow? Cal Trac shocks best buy for the buck. 90/10 and adjustable rears. Can you run roller tappets? Comp makes a roller conversion with special tie bars that go right in a Mopar. Just got some for our old Top Stock motor. I got some more things. email me jefft@southlanddodge.com or 985-804-6161

Re: Mopar 8 3/4 question
 

Wow, just a real nice car. This is what stockers should be. Congrats on a well done car

Kevin

Re: Mopar 8 3/4 question
 

Thanks for the kind words and good ideas. It has been a lot of trial and error. What works on some cars just seems not to work on all.
I am not sure who makes the aluminum spool other than Mark Williams. We do not have one of his spools in the car now so we would have to buy both.
We did switch to a solid roller from the Shubecks and solid cam we started with.
A lighter driveshaft might be in the plan also.

Has anyone seen a decent gain from reducing the rotating weight in the drivetrain ?
Jeff I did send you an email.

Thanks Again

Re: Mopar 8 3/4 question
 

About no gains here. Sounds good, but nothing on the time slips. Maybe something there for a low hp car. Larger the diameter the bigger the gains. Inertia is a b*tch.
Those steel wheels are a place you could notice something.

I cleaned the splines out of the right side of an aluminium spool on the staring line at Memphis once. It was no faster than my lightened steel Strange spool. 5 lbs lighter.
My MT slicks are 4 hundredths quicker than my same size Goodyears. Both dead hook. MTs are 5 lbs each lighter, but on a 31" circle, not a 9" circle. I have seen no gains from aluminium drive shafts either. 3" diameter. You think together they just HAVE to be worth something, even though we can't often prove it.

Light wheels (15" diameter ) would likely be worth a hundredth or two over steel wheels.

Re: Mopar 8 3/4 question
 

Thanks for the reply Ed. Due to the class rules the only wheel choices are the ones we have or the rallye wheels. They did not have an aluminum wheel option in 1971.

We were hoping for some return on a rather large investment. How about some of the trick coatings or treatments that are applied to the ring gears and bearings ? It sure does sound like all together we would realize some gain. If we end up doing it, we were thinking of doing the switch at the track for a real comparison.

Thanks
Gene

Re: Mopar 8 3/4 question
 

Can't give you exact A-B comparision but so far I'm not convinced, my theory is axles,spool,gears won't make as much difference as parts of bigger diameter such as tire. I believe smaller diameter less difference it will make.

If you are'nt making any other changes maybe you can tell us on here for sure. LOL

I like the car, how much does it spin? picture looks like tire is hooked pretty good are they regular old compound,or are they a some kind of soft compund,thinner sidewall version?
I will check out website,but will ask where do they race at?

Mike Taylor 3601

Re: Mopar 8 3/4 question
 

The launch is barely above idle and you roll into it. How fast you roll into it depends on how well the track hooks. For us MIR has the best hook all season hence the best 60"s and best ET's.
The tires are reproductions purchased from Kelsey tire. No real tricks but a little prep goes a long way.

We have raced at various tracks including Lebanon Valley, MIR, Cecil, US 131, National Trail , Virginia Motorsports Park, Englishtown and Beaver Sprimgs. Not every track each year but we do travel.

Re: Mopar 8 3/4 question
 

Nice car!
The changes you want to make may not make the car quicker, but it shouldn't slow it down either. If you have a minimum weight you could take the weight saved from the drive train and put it somewhere to help the car hook better.
I read about this class somewhere, very impressive cars, look completely showroom stock and run some unbelievable times on stock tires.

Re: Mopar 8 3/4 question
 

This in itself will pick the car up.

What I would suggest is taking advantage of this and move weight to areas that will allow you to full throttle the car off the line.
Are you allowed to use a ignition system that would allow you to alter the ignition curve in an attempt to calm the power slightly on the hole-shot in a effort to get the car to leave quicker?

Re: Mopar 8 3/4 question
 

I have the lightest stuff made in my car, and some of those items may be massaged a bit;)

I believe that 1 of those items alone may not be worth much or "anything", but what's ten of them worth. You have to be tenascious and cut, grind, shorten, drill or lighten anything that turns. Email me if you want at wadeowens2007@yahoo.com

BES built an engine for a red 71ish Mustang that ran into the 9's in a similar class. Those cars are unbelievable!

Wade