Mercury Cougar Owners banner

1 - 18 of 18 Posts

·
Registered
Joined
·
315 Posts
Discussion Starter #2
A little more info, 71Xr7 85 5.0 c6 9" 3.00, eldlebrock preformer rpm intake with holley 600cfm, and hei distributor, everything else looks stock. wondering about maybe a overdrive trans and anything else to push her to around 150-160+
 

·
Registered
Joined
·
4,059 Posts
Seems like you’re doing pretty good given the weight/aerodynamic limitations of the car.
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p> </o:p>
Like Poohbair said, the heads on the ’85 5.0 sort of ran out of steam after 4k – grab a set of later 5.0 heads & it will help.
<o:p> </o:p>
Look at it this way: the late 80’s 5.0 Mustangs weighed about 3,100 lbs & topped out a bit over 140 with a 5 speed & a 2.73 rear. That equated to a 1.86 final drive ratio.
<o:p> </o:p>
You must be at a 400 lb disadvantage, with similar HP (probably lower RWHP, given the C6) and a steeper gear.
 

·
Registered
Joined
·
223 Posts
Seems like you’re doing pretty good given the weight/aerodynamic limitations of the car.
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p> </o:p>
Like Poohbair said, the heads on the ’85 5.0 sort of ran out of steam after 4k – grab a set of later 5.0 heads & it will help.
<o:p> </o:p>
Look at it this way: the late 80’s 5.0 Mustangs weighed about 3,100 lbs & topped out a bit over 140 with a 5 speed & a 2.73 rear. That equated to a 1.86 final drive ratio.
<o:p> </o:p>
You must be at a 400 lb disadvantage, with similar HP (probably lower RWHP, given the C6) and a steeper gear.
I had my 89 GT 2.73 gear/ 5 speed up to 137 mph in fourth gear. Fifth gear was useless for anything but MPG at a cruise on the highway. Got close to 30 MPG at 65-70 mph. I did try fifth at about a buck thirty once and hit my head on the windshield. Just too tall and not enough nuts.

Bill
 

·
Registered
Joined
·
315 Posts
Discussion Starter #6
Advice on some heads? Looking at 2.73's all I see is 8.8"? Switching out my 3.00 would include redoing speedo gear and what else? Detroit Locker? Good idea or no? I want to make this 302 as powerful as possible without stroking it or blowing it, ahahah seriously though
 

·
Registered
Joined
·
4,059 Posts
Advice on some heads? Looking at 2.73's all I see is 8.8"? Switching out my 3.00 would include redoing speedo gear and what else? Detroit Locker? Good idea or no? I want to make this 302 as powerful as possible without stroking it or blowing it, ahahah seriously though
The heads got better in '87, but heads from a late model explorer are basically GT 40 heads. Do a search on this forum & you'll find what you seek. You should be able to find gears in the 2.79 range for your 9". A locker is not necesary given your quest for top end, but a "get out of jail free" card might be. You'd need a new speedo gear after changing the rear gear for the speedo to be accurate.
 

·
Registered
Joined
·
4,059 Posts
IIRC, '69-'73 all had 9" rears, with 3.00 gears the most common. There is a 2.91 gear out there, but it hardly seems worth it for the slight difference in rpm.

You are gonna need a lot of HP to push that tub to 150. And Z rated tires.

Depending on tire size, you could hit 150 with your 3.00 rear if you could get your motor to turn 6-6,500 rpm That will take some mods.
 

·
Registered
Joined
·
5,633 Posts
Hmmm... with a 3.0 rear, at 4500 RPM with 26.5" tires (225/70-14) you would be doing 117.8 mph. So to get to 150 you would need to turn that thing right at 5750 RPM. If you could get enough torque It sounds doable.
 

·
Registered
Joined
·
304 Posts
My 69 has a 2.75 rear end and i was able to do 3/4 of an inch past 120 at almost 6000 RPM. I was way to scared to stare at the gauges to long. I lost that race to a Trans Am. And learned a lesson. Don't touch the brakes to hard at that speed.
 

·
Registered
Joined
·
315 Posts
Discussion Starter #12
Hmmm... with a 3.0 rear, at 4500 RPM with 26.5" tires (225/70-14) you would be doing 117.8 mph. So to get to 150 you would need to turn that thing right at 5750 RPM. If you could get enough torque It sounds doable.
im running 225 70 in rear and smaller in front at 4500-4600 was sitting at 120 riding smooth but motor sounded like she didnt have much more
 

·
Contributing Sr Motorhead
Joined
·
5,470 Posts
In my yout', I had my old '85 T-bird Turbo Coupe up to 135+, and that was all she wrote. Much more aerodynamic that a 'brick' Classic Cougar, and only the little 180hp turbo 2.3L with the boost pegged at 12psi in 4th... 3.45 rear gears and yes, Z-rated tires!

My 2-ton brick of a '89 Crown Vic's speedo is still climbing like a scalded cat when I go through the 1/4-mile finishline at 110. Never tried to take it higher on the street.
 

·
Registered
Joined
·
227 Posts
I had a 79 Mustang with a 302 that would turn 129 mph and 10.9 in the quarter, with 5.43 gears. Of course I had 32" Goodyear slicks.

As recommended above, upgrade to an aftermarket set of heads. All else fails start reducing any rotating weight (rods, pistons, wheels, rotors, etc. also remember as you reduce that rearend ratio, to gain top end, you'll be giving up acceleration.

Then stick a 100 horse nitrous kit on it and maybe a rollbar. Remember, speed kills. Cougars are built to old school safety standards.
 

·
Registered
Joined
·
1,072 Posts
Go rent a corvette for the weekend and get the speed demon out of your system. You don't want to wreck your own car to find out how fast it can go.
 

·
Premium Member
Joined
·
13,577 Posts
Would you be open to the idea of me buying a life insurance policy on you with myself as the beneficiary? :buck:
 

·
Registered
Joined
·
5,633 Posts
The road racing Cougars entered corners at better than 100. Now none of us is Dan Gurney or Parnelli Jones, but 120 in a straight line is not the end of the world... Stopping might be.
 
1 - 18 of 18 Posts
Top