I've always heard IRS is lousy in drag racing.
There is a group,FAST Factory Appearing Stock Tires. Cast Iron exhaust Manifold mufflers, factory intake manifold, interior, stock appearing IRS. Actual Firestone bias ply F 60's.
I've always heard IRS is lousy in drag racing.
There is a group,FAST Factory Appearing Stock Tires. Cast Iron exhaust Manifold mufflers, factory intake manifold, interior, stock appearing IRS. Actual Firestone bias ply F 60's.
In reply to frenchyd :
IRS in them isn't too bad for drag racing. The bigger issue was once something lets go, either a U joint it stub, you have a flailing half shaft pounding through the floorpan to the back of the seat and the wheel flops around. Those FAST cars are unreal to watch. They do a great job of looking stockish.
In reply to frenchyd :
It's all in the prep. Stock with soft factory subframe bushings introduces a lot of slop on a hard launch, you get wheelhop, and then stuff starts breaking.
They may look stock on the outside but under the covers everything on those cars has been changed. Scott Tieman has gone 9.990 at 136mph in his 1968 Firebird; a real stock Firebird wouldn't go that fast if you dropped it off a cliff. 
When I worked at Year One my old boss Phil Brewer had a Nova that he and his Dad ran in FAST. This thing looked right...but was cheated up to an insane level. Spare tire was full of concrete, cylinder heads were aluminum painted to look iron. Intake manifold and exhaust manifolds were extrude honed to the hilt. The passenger side of the bench seat was gutted. Trans had some crazy shift kit. The suspension was set up to ONLY launch on bias ply tires. They took all their years of dirt track...creativity...and channeled into the Nova. It was insane to watch it run 12s way back then.
My friend has been shopping for a car to drag race in the Factory Stock/Pure Stock class.
He's owned a bunch of Fords, couple of escort GT's, a maverick, a 68 mustang, multiple trucks, two probe GTs, a crown Victoria, and more.
Over the last couple of years, he bought a hoard of Chevrolet parts along with a 68 camaro SS convertible with a 454. All of that has been sold, and his search for a race car has been all Chevrolet cars: Camaro, Corvette, camaro, camaro, nova, Chevelle, Camaro...
I got this text from him on Sunday, he just picked this up. I have to say, I really didn't see this coming, but I'm really happy that he made this choice. It just seems right.
I'm lobbying hard for CAM-T autocross.
In reply to Floating Doc (Forum Supporter) :
Your buddy should swap out the front fenders for the cheapest aftermarket pieces he can find. Back when I worked at Mustangs Unlimited we paid $14 per fender wholesale for the flimsiest stamped sheetmetal I've ever seen. You could pick up one of those fenders and it would go "wubba wubba wubba" it was so thin. Just don't lean on them.
Loosely searching the net:
Car & Driver Yearbook 1967, '67 Vette 427/435 4-speed 3.36 rear, qtr mile 12.8 @ 112 mph, 0-60 in 5.4 sec.
Motor Trend April 1967, '67 Vette 427/435 4-speed 3.55 rear, qtr mile 13.8 @ 104 mph, 0-60 in 5.5 sec.
frenchyd said:Firestone bias ply F 60's.
This is what get's me. Now I understand these are not the same tires as were actually sold back in the 60's. But damn that's insainly fast for an old fashioned style street tire. People who were running these speeds back in the day were doing it on 'real' period race tires. I just can't imagine what a car feels like on those tires while pulling an average of 0.75G for the whole run. Depleted uranium nad's (or ovaries) to ride that one down the strip.
I've seen F.A.S.T class cars run in person, they're astounding. I remember when they were knocking on the E.T.s for serious safety gear and there was a huge debate about how to handle it, because rollcages obviously aren't stock appearing, but then not allowing them would just turn it into bracket or throttle-stop racing.
The Pure Stock cars were also fun just to give you an idea how some of the legends weren't what you thought. They ran a qualifier and then were paired up in close match-ups for heads-up 2-out-of-3 shootouts. There was a Yenko 427 Camaro matched up with a 327/4-speed '67 Biscayne 2-door post coupe. The Biscayne whomped the Yenko every single run.
In reply to NickD :
The main reason I'm excited is everybody has said repeatedly that IRS has to be switched to straight axle to run decent 1/4 mile times.
I know my Challenge car entry won't go anywhere near that fast but at least it's OK.
In reply to frenchyd :
It depends on the IRS geometry really. Guys have gone 6s with MkIV Supras on the factory IRS, Mark Carlyle did 6.80s with a C6 Corvette with the factory IRS, Cleetus McFarland has done 7.40s with his C6 and 7.80s with his stick-shift C5 Vette Kart. I'm not intrinsically familiar with Jag IRS and how it does in drag-racing service (I don't imagine many are, on that second part) but yes, blanket statements like "You can't go fast with IRS" are definitely not true.
In reply to frenchyd :
who is everyone? And what do you mean by "decent"?
NickD said:In reply to frenchyd :
It depends on the IRS geometry really. Guys have gone 6s with MkIV Supras on the factory IRS, Mark Carlyle did 6.80s with a C6 Corvette with the factory IRS, Cleetus McFarland has done 7.40s with his C6 and 7.80s with his stick-shift C5 Vette Kart. I'm not intrinsically familiar with Jag IRS and how it does in drag-racing service (I don't imagine many are, on that second part) but yes, blanket statements like "You can't go fast with IRS" are definitely not true.
The equipment we race with is wonderfully stout. ( it's a Dana44 center section and forged axles.). Completely adjustable. The Geometry is completely adjustable. So I can keep the wheels straight and vertical through 90% of its movement. Stock the whole movement is needle bearings but we swap the outer ends for rod bearings to make toe easily adjustable.
cruisermatt said:In reply to frenchyd :
who is everyone? And what do you mean by "decent"?
I have had only one run on a drag strip in My life. The sum total of what I know wouldn't cause a knats eye to blink.
So I listen to everybody. And that's the consensus .
As far as decent? Who knows?!? That may be the first ever pass in anger it makes. I'm kinda hoping Calvin Nelson or his dad will take a pass to set a benchmark for the guys.
I'd like one of the "pro" auto crossers to give it a shot as well.
frenchyd said:NickD said:In reply to frenchyd :
It depends on the IRS geometry really. Guys have gone 6s with MkIV Supras on the factory IRS, Mark Carlyle did 6.80s with a C6 Corvette with the factory IRS, Cleetus McFarland has done 7.40s with his C6 and 7.80s with his stick-shift C5 Vette Kart. I'm not intrinsically familiar with Jag IRS and how it does in drag-racing service (I don't imagine many are, on that second part) but yes, blanket statements like "You can't go fast with IRS" are definitely not true.
The equipment we race with is wonderfully stout. ( it's a Dana44 center section and forged axles.). Completely adjustable. The Geometry is completely adjustable. So I can keep the wheels straight and vertical through 90% of its movement. Stock the whole movement is needle bearings but we swap the outer ends for rod bearings to make toe easily adjustable.
The parts you mention aren't the the weakest link. (though 8 1/2" ring gears and 30 or even 19 spline axles can't really be considered "wonderfully stout")
The aluminum hub carriers won't carry nearly as much power as the differential.
And getting the power to the ground is a whole 'nother issue in itself.
NickD said:In reply to frenchyd :
I'm not intrinsically familiar with Jag IRS and how it does in drag-racing service (I don't imagine many are, on that second part)
A lot of British hot rods used to run Jag IRS so there's been plenty of them drag raced. Pretty sure Nic Mann's Morris had a Jag IRS and ran 11s and was set up for hillclimbs more than drag racing. I'd bet there have been some 10 sec and maybe even 9 sec runs with a Jag IRS.
Cooter said:frenchyd said:NickD said:In reply to frenchyd :
It depends on the IRS geometry really. Guys have gone 6s with MkIV Supras on the factory IRS, Mark Carlyle did 6.80s with a C6 Corvette with the factory IRS, Cleetus McFarland has done 7.40s with his C6 and 7.80s with his stick-shift C5 Vette Kart. I'm not intrinsically familiar with Jag IRS and how it does in drag-racing service (I don't imagine many are, on that second part) but yes, blanket statements like "You can't go fast with IRS" are definitely not true.
The equipment we race with is wonderfully stout. ( it's a Dana44 center section and forged axles.). Completely adjustable. The Geometry is completely adjustable. So I can keep the wheels straight and vertical through 90% of its movement. Stock the whole movement is needle bearings but we swap the outer ends for rod bearings to make toe easily adjustable.
The parts you mention aren't the the weakest link. (though 8 1/2" ring gears and 30 or even 19 spline axles can't really be considered "wonderfully stout")
The aluminum hub carriers won't carry nearly as much power as the differential.
And getting the power to the ground is a whole 'nother issue in itself.Corvettes up to the rear engine one used the same rear end assembly as did the 427 Cobra.
In reply to Adrian_Thompson (Forum Supporter) :
The video posted shows that they're shaved into slicks. With modern rubber compounds, I'd imagine they're better for traction than real 1960s slicks were.
In reply to Saron81 :
According to the owner they buy them right from Coker tire and shave them. Then run very low tire pressure to get the wrinkle wall effect.
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