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Any Dirt Track Mopars?

weedburner

Active Member
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5:26 AM
Joined
Nov 14, 2018
Messages
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Location
WA
Back in the early '80's I decided to build a dirt latemodel car for our local dirt track. The class had an engine setback rule, basically the #1 spark plug could be a maximum of 10.5" behind the upper balljoint centerline. The iron 440 out of my '70 Challenger was going to make the car pretty nose heavy compared to the rest of the field with sbc's, one guy even had an aluminum block. With more time than money, I decided to get creative.

My solution was to install the 440 in the chassis backwards. The BBM rear spark plug is much closer to the back of the engine than the #1 plug is to the front, also turning the engine around moved the water and power steering pumps much farther back. It also moved the oil pump from the left front engine location to a much better right rear location. The tech guys complained that the #1 plug was now in the rear, but hard to argue when we bolted a stock intake with numbered intake runners on the engine backwards, stock intake then said #1 is up front. The net effect of the flipping the engine around was like gaining an additional 4" of engine setback. Radiator was also moved to the rear, in the deck behind the driver.

In addition to the backwards engine, I also moved the transmission much farther back with a 18" long input shaft. Drilled a couple holes along the crank/balancer parting line so I could add a couple dowels to serve as additional keys, then made a small splined hub that bolted to the face of the balancer to drive the transmission. Input shaft plugged directly into the hub, there was no clutch. Bolted the transmission to the chassis instead of the engine, eliminated the weight of a bellhousing.

Second nite out, they dragged what was left of the car into the pits on it's roof...

LM1c1986.jpeg


Same chassis after a few repairs...

LM2b.jpeg


The backwards engine also gave me a reverse rotation drivetrain, easy to account for by modifying the quick change rear. Basically, flip the spool and move the ring gear over to the other side of the pinion.

LM4.jpeg


After breaking a few input shafts, I made a lite sheet metal case trans that had a motorcycle clutch in the countershaft. I still have that bellhousing adapter that went between the timing cover and trans...

LM7b.jpg


As far as I know, the car above was the last BB Mopar to win a feature at our local track...

LM4a.jpeg


After a series of backwards BB Mopar cars, I built a double engine dirt latemodel powered by a couple Mazda 13B rotaries...

LM8n.jpeg


LM8kc.jpeg


Grant
 
Back in the early '80's I decided to build a dirt latemodel car for our local dirt track. The class had an engine setback rule, basically the #1 spark plug could be a maximum of 10.5" behind the upper balljoint centerline. The iron 440 out of my '70 Challenger was going to make the car pretty nose heavy compared to the rest of the field with sbc's, one guy even had an aluminum block. With more time than money, I decided to get creative.

My solution was to install the 440 in the chassis backwards. The BBM rear spark plug is much closer to the back of the engine than the #1 plug is to the front, also turning the engine around moved the water and power steering pumps much farther back. It also moved the oil pump from the left front engine location to a much better right rear location. The tech guys complained that the #1 plug was now in the rear, but hard to argue when we bolted a stock intake with numbered intake runners on the engine backwards, stock intake then said #1 is up front. The net effect of the flipping the engine around was like gaining an additional 4" of engine setback. Radiator was also moved to the rear, in the deck behind the driver.

In addition to the backwards engine, I also moved the transmission much farther back with a 18" long input shaft. Drilled a couple holes along the crank/balancer parting line so I could add a couple dowels to serve as additional keys, then made a small splined hub that bolted to the face of the balancer to drive the transmission. Input shaft plugged directly into the hub, there was no clutch. Bolted the transmission to the chassis instead of the engine, eliminated the weight of a bellhousing.

Second nite out, they dragged what was left of the car into the pits on it's roof...

View attachment 1576156

Same chassis after a few repairs...

View attachment 1576150

The backwards engine also gave me a reverse rotation drivetrain, easy to account for by modifying the quick change rear. Basically, flip the spool and move the ring gear over to the other side of the pinion.

View attachment 1576151

After breaking a few input shafts, I made a lite sheet metal case trans that had a motorcycle clutch in the countershaft. I still have that bellhousing adapter that went between the timing cover and trans...

View attachment 1576153

As far as I know, the car above was the last BB Mopar to win a feature at our local track...

View attachment 1576152

After a series of backwards BB Mopar cars, I built a double engine dirt latemodel powered by a couple Mazda 13B rotaries...

View attachment 1576154

View attachment 1576155

Grant
I must say that I am impressed with the way your mind works! Real cool design solutions.
Mike
 
Far out!! I guess it was all worth it, you got the win. Definitely an engineering marvel.
 
440 in a late model..Your a wild man! Very cool.
 
After reading something as weird and unconventional as that, your screen name makes sense.



01 funny 7.gif
 
reading something as weird and unconventional as that, your screen name makes sense.
Thanks for the comments guys.

Here's where weedburner comes from...

2010d.jpg


I've been told it looks real cool with the front end up in the air at nite, almost like one of those cartoon t-shirts with flames shooting out. Sometimes i'll put a little extra retard in the box just to get good flames :)

When I remove the caps, i have a set of very short extensions that have "tongues" that extend up into the collector to seal off the rest of the exhaust system. The idea was to restore the efficiency of the collectors when the headers are un-capped....

collectorinserts.jpg


I could have made a great pot smoker, but spent all my money on car parts.

Grant
 
Anyone that dares to innovate puts themselves at risk of silly comments, often by those with far less skill than you have.
Thank you for being good natured about the joke. The backwards engine idea is certainly unique.
 
Show us some pictures of the Weedburner car, please.
 
Kool stuff Grant!
I love what you have done to Clutchtamer and now I see all the work behind it!
Great detailed write up!!!
 
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