Best way to proceed with improving up 427 Windsor street setup

[SPF1061]

Originally Posted by ralc

had a similar problem. Nelson Specialties in Mooresville, NC did the distributor and back on the same dyno, it picked up 46 HP He is amazing. Turns out the advance curve was way off and the gear was grinding into the block

Just another vote for Nelson Specialties. My idle was hanging up at around 1200rpm and I determined that the distributor advance was not fully returning. Sent the dizzy to Nelson for a blueprint/rebuild. Solved the idle problem and the seat of the pants performance gain was noticeable. Very knowledgable and helpful folks. Highly recommended.

[Ace23]

I'm having a bit too much fun driving right now to pull the motor. I am considering a gearing change. I run 315/35/17 and I have a TKO-600 .82 with a 3.31 rear gear. I think going to a different gear could really take advantage of the current cam in the car for right now.My car does not buck but it likes to be about 2000+ when cruising. I am leaning towards 3.91 ratio and possibly going with a .64 5th gear. The gearing calculator shows 38mph-48mph in 4th between 2000-2500rpm and 5th will give me 59mph-74mph between 2000-2500rpm. That seems like a pretty good mix of back road and interstate speed. Does anyone run this combo or having any advice? The .82 does not really work out too well with anything much higher than 3.46. I loath driving down the road at 3000rpms when cruising so the .64 is pretty attractive to me. I wouldn't completely rule out 4.10's either......I think the largest issue will be traction as the current setup is 590HP / 570TQ. Just an inexpensive way to make the car feel a lot faster and it could use more gear for sure.
Thanks

[olddog]

Originally Posted by Ace23

I'm having a bit too much fun driving right now to pull the motor. I am considering a gearing change. I run 315/35/17 and I have a TKO-600 .82 with a 3.31 rear gear. I think going to a different gear could really take advantage of the current cam in the car for right now.My car does not buck but it likes to be about 2000+ when cruising. I am leaning towards 3.91 ratio and possibly going with a .64 5th gear. The gearing calculator shows 38mph-48mph in 4th between 2000-2500rpm and 5th will give me 59mph-74mph between 2000-2500rpm. That seems like a pretty good mix of back road and interstate speed. Does anyone run this combo or having any advice? The .82 does not really work out too well with anything much higher than 3.46. I loath driving down the road at 3000rpms when cruising so the .64 is pretty attractive to me. I wouldn't completely rule out 4.10's either......I think the largest issue will be traction as the current setup is 590HP / 570TQ. Just an inexpensive way to make the car feel a lot faster and it could use more gear for sure.
Thanks

I have a 26.3" diameter tire and a TKO 600 with the .64 5th gear. When I got the car it had a 3.5 rear end.

In 4th gear I tacked 2550 rpm at 57 MPH -- this is getting loud (typically drove 50 if no traffic so I could talk to the wife)
In 5th gear I tacked 1625 rpm at 57 MPH -- Quiet - careful on the throttle! Don't get it bucking) dang it shift back to 4th.
In 5th gear I tacked 1850 rpm at 65 MPH -- not happy until you get a speeding ticket

My engine will not run well below 1800 and it would prefer 2000.

I changed to a 3.92 rear end ratio
In 4th gear I tacked 2850 rpm at 57 MPH -- wow is this loud. Amazing the difference 300 rpm makes
In 5th gear I tacked 1825 rpm at 57 MPH -- quite and manageable
In 5th gear I tacked 2000 rpm at 62 MPH -- engine loves the highway

Basically I went from a useless 5th gear to a useless 4th gear, by choice. I felt that was the best compromise, as I can drive 55 MPH in 5th gear.

I hate the .64 5th ratio. They should call it 6th gear cause there is no 5th gear. I hate the huge rpm change from 4th to 5th. I had to rebuild the rear end, as I had a bad bearing, and it was cost effective and simple to change the ratio. It's a lot better than it was, but I would still prefer the .82 5th gear. If I do change to the .82, I will change back to the 3.5 rear end.

[8litercobra]

I am replacing a 2.32/1.69/1.29/1 toploader with a T56 from Rockland Standard - 2.29/1.60/1.21/1.00/0.84/0.67. My Unique FIA has a 3.54 rear, with 245/15 Avon CR6ZZs.

Previously, I had another cobra with 3.31 rear gears and the 2.32 toploader. I really like the 4 speed CR gearing, and the T56 is very close.

The T56 is a heavy thing....I'm still not over the hard part of the install. But I went from an iron block & head windsor to an aluminum Dart/Kaase headed engine. It will be lighter than before! Brent Lykins gathered all my clutch parts - knowledgable and quick!

I'm booked for the next few weeks so getting this thing running is a ways off. There's always a few more details than I can see.

[Luce]

Wait a minute. Isn't the gear supposed to rub on the block? The clearance dimension for the end play in the distributor keeps the top of the distributor bushing from being the thrust face as it doesn't have positive lubrication.

Yea, I know it's a 5 month old thread. I was dumbfounded to learn that SBC dizzy is on the other side of the cam and the thrust tries to push the distributor out of the engine unlike Ford and Mopar where the thrust is pulling the distributor down (or the drive shaft in the case of the Mopar)

My block has a nicely machined surface for the dizzy gear to rub on.

[RET_COP]

Sounds like your in a nice spot--just drive it. I have that combo and if anything a change to 3.55 because of the aluminum FW I have is something I may do, but with your TQ of 570 and no bucking and you want Back Roads AND Interstate driving I think you should stay. If you change the 5th gear to .64 you could then bump it up but 570 TQ !!? yikes

[jhv48]

If you go for the .64 fifth gear, you're going to hate the 1000 rpm drop when you go from fourth to fifth. I switched from the .64 to the .82 as I was tired of having a useless fifth speed. Granted I could cruise at 75 mph with the engine barely running, but when I wanted some spirited passing, I had to drop to fourth. Now I turn 2600 rpm at 70 mph and my engine is right in its happy zone if I want to accelerate or pass.

Leave it as it is.

[Ace23]

Originally Posted by RET_COP

Sounds like your in a nice spot--just drive it. I have that combo and if anything a change to 3.55 because of the aluminum FW I have is something I may do, but with your TQ of 570 and no bucking and you want Back Roads AND Interstate driving I think you should stay. If you change the 5th gear to .64 you could then bump it up but 570 TQ !!? yikes

I have a pretty good amount of duration in the cam but I'm guessing the 112LSA has something to do with it not bucking. The engine dyno is what was showing the 570TQ

Originally Posted by jhv48

If you go for the .64 fifth gear, you're going to hate the 1000 rpm drop when you go from fourth to fifth. I switched from the .64 to the .82 as I was tired of having a useless fifth speed. Granted I could cruise at 75 mph with the engine barely running, but when I wanted some spirited passing, I had to drop to fourth. Now I turn 2600 rpm at 70 mph and my engine is right in its happy zone if I want to accelerate or pass.

Leave it as it is.

If I went to a .64 you would need to run some pretty stout gears. After looking at the gearing calculator the 3.73 might be about as far as I would be willing to take it with the .82 5th. 70MPH with the 3.73 would leave me about 2800rpm which isn't too bad. This may be the least expensive thing to try first. Brent said throw the 4.10's in it but I think I do too much higher speed cruising for that.

[Shootnride]

There have been quite a few threads on this forum about this subject and it always fascinates me just how different our individual preferences are concerning gear ratios and especially the .64 vs .82 overdrive ratios. I have a 456 cu in FE making about 500/500 HP/TQ. With the cam I have in my motor it likes to run above 2000 RPM. I'm running 15" tires, 3.73 rear end and .64 5th gear. I'm turning about 2300 RPM at 70 MPH in 5th gear, which suits me perfectly. When I drop to 4th gear at 70 MPH I'm turning about 3300 RPM. As JHV48 said, it's a 1000 RPM drop between 4th and 5th but I find that I still have plenty of torque for passing.

Ted

[8litercobra]

What Shootnride said - "it always fascinates me just how different our individual preferences are concerning gear ratios and especially the .64 vs .82 overdrive ratios". I just put in a T56 and have both!! Still finishing up the install......wish me luck.

[Ace23]

Originally Posted by Shootnride

There have been quite a few threads on this forum about this subject and it always fascinates me just how different our individual preferences are concerning gear ratios and especially the .64 vs .82 overdrive ratios. I have a 456 cu in FE making about 500/500 HP/TQ. With the cam I have in my motor it likes to run above 2000 RPM. I'm running 15" tires, 3.73 rear end and .64 5th gear. I'm turning about 2300 RPM at 70 MPH in 5th gear, which suits me perfectly. When I drop to 4th gear at 70 MPH I'm turning about 3300 RPM. As JHV48 said, it's a 1000 RPM drop between 4th and 5th but I find that I still have plenty of torque for passing.

Ted

I will swap to a . 64 one day if I keep the TKO-600. I cruise 70mph+ a pretty good bit and it just makes since if you start throwing gears in the car.

Originally Posted by 8litercobra

What Shootnride said - "it always fascinates me just how different our individual preferences are concerning gear ratios and especially the .64 vs .82 overdrive ratios". I just put in a T56 and have both!! Still finishing up the install......wish me luck.

It has been said that it is expensive and heavy but the T-56 offers awesome gearing selection. I think you will be pleased.

[Gaz64]

Originally Posted by 8litercobra

What Shootnride said - "it always fascinates me just how different our individual preferences are concerning gear ratios and especially the .64 vs .82 overdrive ratios". I just put in a T56 and have both!! Still finishing up the install......wish me luck.

Sounds like you have a .80 5th and .64 6th.

Yours would be all closer ratios with 1st to 3rd all taller than the box we get here.

A much better ratio combo than the useless .74:1 5th and .5:1 6th.

[Ace23]

Yes, back in 2004 when the motor was built there is an email printed out in my receipt booklet that explains that there was an early set of 2" headers built for the SPF and this was the 2nd set they built. They fit the car well but obviously the bolt holes in the flanges were higher than they needed to be.

[blykins]

Looks like a 10.5" diaphragm plate with a 500 series disc. Rated for 525-550 hp.

[RET_COP]

Probably a McLeod super street pro Diaphragm with a dual friction disk. I have the same setup with an Aluminum Flywheel behind a 351w 495HP TKO 600 and 3.27 eaton trutrac with moser 31 spline axles. Absolutely no issues with the McLeod Aluminum 15lb. flywheel and I had the McLeod billet steel in there last year. The response from low rpms is Quicker than the steel FW. I got away from the thought of drag racing to autocross that's why I switched.

[Ace23]

Originally Posted by blykins

Looks like a 10.5" diaphragm plate with a 500 series disc. Rated for 525-550 hp.

Originally Posted by RET_COP

Probably a McLeod super street pro Diaphragm with a dual friction disk. I have the same setup with an Aluminum Flywheel behind a 351w 495HP TKO 600 and 3.27 eaton trutrac with moser 31 spline axles. Absolutely no issues with the McLeod Aluminum 15lb. flywheel and I had the McLeod billet steel in there last year. The response from low rpms is Quicker than the steel FW. I got away from the thought of drag racing to autocross that's why I switched.

What do you guys think about the McLeod Street Extreme? Looks like it is rated for 700hp.

I have also been looking at the gearing calculator and I've spent some time looking at the MPH in all gears instead of focusing on just the 6th...... When you consider the change in tire size going from a 315/35/17 to a 325/50/15 plus the changes in gear ratios the gearing isn't as drastic as I thought it would be. Looks like you need to run a minimum of a 4.10 to make it worth wild.

[RET_COP]

Be careful with the Street Extreme, the only difference between the 550HP and the 700HP is the disk. The 700HP doesn't have an organic side and will probably chatter more off idle. I really don't think you need it. The Cobra is a light weight car.
As far as transmissions and gearing, you can drive yourself nuts with the formula. What do you plan on doing with the car. Are you a long hauler (Highway), do you just cruise the streets? Your car is cammed like mine. I have no issues with the TKO 600. I've had both the .64 and the .82. with a 27" tire. My motor is cammed like yours also. If I had one complaint it would be the large rpm drop of the .64, but 2200 rpms on the highway was quiet. .73 would have been ideal. I'm more concerned about my gearing for the autocross ( I run tight courses in my area, and will try 3.55 rear gears. So, you see what I mean, it really depends on what your going to do with your car.

[blykins]

I do a million of these combos....if you're wanting something to hold big horsepower and not chatter or have on/off engagement, you need a twin disc. Otherwise you're stuck with a very aggressive single disc that won't be fun on the street.

As for the rearend, a 3.73 to 4.10 is usually the sweet spot for these cars. Going from a 3.27-3.31 to either one of those ratios will be a dramatic difference.

[Ace23]

Originally Posted by RET_COP

Be careful with the Street Extreme, the only difference between the 550HP and the 700HP is the disk. The 700HP doesn't have an organic side and will probably chatter more off idle. I really don't think you need it. The Cobra is a light weight car.
As far as transmissions and gearing, you can drive yourself nuts with the formula. What do you plan on doing with the car. Are you a long hauler (Highway), do you just cruise the streets? Your car is cammed like mine. I have no issues with the TKO 600. I've had both the .64 and the .82. with a 27" tire. My motor is cammed like yours also. If I had one complaint it would be the large rpm drop of the .64, but 2200 rpms on the highway was quiet. .73 would have been ideal. I'm more concerned about my gearing for the autocross ( I run tight courses in my area, and will try 3.55 rear gears. So, you see what I mean, it really depends on what your going to do with your car.

I want my cake and I want the ice cream to go with it! My car is purely a street car and all I want is insane roll on power and a cruising gear.....thus I have been looking at the T56 tranny option. I know it cost more but if I can get more aggressive gearing than what I have now and still have a 6th gear for interstate / faster back road cruising then I think I would be really pleased with the car. I have looked at all the .82 TKO-600 combos and the 5th gear is too short when you get into 3.91+......I also don't like the idea of the .64 4th to 5th rpm drop. This new cam Brent specified and all the other freshening that is taking place should make a world of difference.

Originally Posted by blykins

I do a million of these combos....if you're wanting something to hold big horsepower and not chatter or have on/off engagement, you need a twin disc. Otherwise you're stuck with a very aggressive single disc that won't be fun on the street.

As for the rearend, a 3.73 to 4.10 is usually the sweet spot for these cars. Going from a 3.27-3.31 to either one of those ratios will be a dramatic difference.

I have no issue with using a twin disk and I'm not willing to save a few hundred dollars to deal with chatter ect. I think you estimated my HP to be around 550HP with this new cam so while it isn't big horsepower it may future proof the car for future upgrades. I will take a look at the McLeod RST.....I believe this was in my previous 03 Cobra.

[blykins]

I see no benefit in running a T-56. It will be hard on your wallet, not only for the price of the trans, but for the driveshaft and everything else that you will have to buy for it. If you run a twin disc, the midplate will need to be modified for an adjustable ballstud plus you'll have to run a notched fork. Otherwise, it will be hydraulic throw out bearing.

I'm a T-56 hater, plain and simple. Too long, too big around, too heavy, not enough benefit from another gear to spend that much money.

You would not be able to tell any difference in performance between a 3.73 and a 4.10 gear. My $.02 would be to run the TKO 600 you have, put a 3.73 in the rear, and cruise at 70 in the lower 2000's.