5.0 Redline

smeltz · Nov 1, 2010

I just purchased a Factory Five Racing Roadster (Cobra Replica). The car is complete and a few things I know about the car is that it is a 1991 5.0 Crate motor with GT40-P heads Ford racing E303 cam, roller rockers, stock springs, cobra upper and lower intake. The car also has an aluminum flywheel, so the RPM's climb real fast. The car has a rev. limiter set at 5,000 rpm's and I am constantly hitting the limiter. What do you think it could rev to safely? What kind of power do you think this combo is making? Any input would be greatly appriciated. I had a 2006 Mustang GT with a whipple HO supercharger making 501rwhp that I traded on this cobra, I am missing the power but man is this cobra fun to drive.

NIKwoaC · Nov 1, 2010

The "accepted" value for the factory rev limiter is 6250, though I've heard that some cars could be different. Your combo isn't making much power above 6250 anyway, so maybe start there.

If the car has "stock" GT40-P springs (Explorer springs), there might be a reason behind the 5000rpm limiter...

smeltz · Nov 1, 2010

Thanks, I am new to the 5.0 engines what springs would you guys recommend? The car makes great power until the limiter kicks in, I don't want to hurt the engine by over revving it but I think taking it up to 6K would help it out.

Dino Dino Bambino · Nov 1, 2010

smeltz said:
The car has a rev. limiter set at 5,000 rpm's and I am constantly hitting the limiter. What do you think it could rev to safely?

Your combo should make peak HP at around 5200rpm so I'd set the rev limiter 500rpm beyond that i.e. 5700rpm.

phutch11 · Nov 1, 2010

I have essentially the same enigne as you and I shift at about 5700, peak power feels about 5500 or so.

I would set the limiter to stock or 6000.

I have the FRPP springs recommended for the E cam. They are more than fine for that cam.

Good luck...

Mustang5L5 · Nov 1, 2010

Is your tach accurate?

jrichker · Nov 2, 2010

Are you sure you do not have a high speed miss? A faulty TFI module would shut down a warm engine at high RPM.

The TFI module mounted on the distributor is usually the culprit for a high speed miss on a warm engine. If the problem does not occur when the engine is cold, the TFI module is definitely suspect. You may need a special socket to remove the TFI module, but most auto parts stores will have one for $5-$7.

Be sure to use plenty of the heat sink grease on the new TFI and clean the old grease off the distributor.

View attachment 204985

See Automotive Tools Specialty | Auto Mechanic & Technician Diagnostic, Testing Equipment | Thexton

2000xp8 · Nov 2, 2010

How do you know you have a rev limiter set to that number?
I don't know of that many easy ways to set a limiter on these engines.
Most people would probably use an ignition box with a pill. If that's the case pull it out and put one in for 6 grand.
And E cam should be good for about 5500rpm.

I hope your "rev limter" isn't really valve float from the cam.
They feel very similar.

smeltz · Nov 2, 2010

I was told that it is limited to 5,000 RPM, I will need to call and talk to the previous owner. Honestly I am not real crazy about the whole set up. I think I may get a set of aluminum AFR heads and do the whole top section of the motor and have it retuned. I would like to be around 350-400 HP at the crank.
The car runs great until you get to 5K doesn't matter if its hot or cold. That is one thing tha worries me, I was told that it has the oiginal springs, I'm not sure if that E cam is to much for the stock springs.

2000xp8 · Nov 2, 2010

smeltz said:
I was told that it is limited to 5,000 RPM, I will need to call and talk to the previous owner. Honestly I am not real crazy about the whole set up. I think I may get a set of aluminum AFR heads and do the whole top section of the motor and have it retuned. I would like to be around 350-400 HP at the crank.
The car runs great until you get to 5K doesn't matter if its hot or cold. That is one thing tha worries me, I was told that it has the oiginal springs, I'm not sure if that E cam is to much for the stock springs.

Eventually an e cam is too much for stock springs. Some cars take it for a while, some don't.

I just saw a car make 334rwhp with a custom cam, rpm II intake and 165's.
Honestly in a light cobra that would pretty much be equivalent to the 501rwhp in your old gt.
Also would give you a little more rpm to play with, something that you probably got used to with the new mustang, but lost when you went back to pushrods.
Your probably in the 260rwhp hp range now.

smeltz · Nov 2, 2010

Thanks everyone, I love the cobra but I miss the horsepower my 06 GT was putting out. In a straight line the GT would have ate my cobra alive but in the turns this little cobra is like it is on rails!! I just need more power.

JadeGT · Nov 4, 2010

You do know those cars have there own forum.

FFCars.com - Factory Five Racing Discussion Forum - Powered by vBulletin

NIKwoaC · Nov 4, 2010

JadeGT said:
You do know those cars have there own forum.

FFCars.com - Factory Five Racing Discussion Forum - Powered by vBulletin

Nothing wrong with asking 5.0 questions on a 5.0 website.

smeltz · Nov 4, 2010

JadeGT said:
You do know those cars have there own forum.

FFCars.com - Factory Five Racing Discussion Forum - Powered by vBulletin

Very aware of ffcars.com, on it every day, I just figure I would get better advice on here when it comes to the 5.0 engine.

JadeGT · Nov 4, 2010

I was just trying to be helpful and make sure you knew about that site. I was not criticizing anything about your post.

jrichker · Nov 4, 2010

smeltz said:
Very aware of ffcars.com, on it every day, I just figure I would get better advice on here when it comes to the 5.0 engine.

For what it is worth, I think you are right...

5.0 Redline

smeltz

New Member

NIKwoaC

中國製造

smeltz

New Member

Dino Dino Bambino

phutch11

Member

Mustang5L5

That is…until I whipped out my Bissell

jrichker

StangNet's favorite TOOL

2000xp8

smeltz

New Member

2000xp8

smeltz

New Member

JadeGT

New Member

NIKwoaC

中國製造

smeltz

New Member

JadeGT

New Member

jrichker

StangNet's favorite TOOL

Similar threads

5.0 Redline

New Member

中國製造

New Member

Member

That is…until I whipped out my Bissell

StangNet's favorite TOOL

New Member

New Member

New Member

中國製造

New Member

New Member

StangNet's favorite TOOL

Similar threads

Privacy & Transparency

Privacy & Transparency