[jperickson2001]

Here is a dirty little secret about buying a new carb. Go on eBay and search for say, “850 Holley double pumper refurbished”. You will pay roughly 50 cents on the dollar. Any returns Holley gets, they dismantle, clean, reset to factory specs, and sell on eBay as factory refurbished. Looks new because it is. I’d go 850 myself. Around town you will only be opening the front barrels. Full wide open when you want full power, that 850 will shine. NASCAR uses 15x3 air cleaners because they support the power they make. If it doesn’t fit, get a extra low dropped bottom air cleaner. Race shops have them. Covers the carb almost entirely.

 

[phils88gt]

That's part of your problem. That's not much cam in a 440" motor. I would expect mid 230s intake and mid 240s exhaust in a 400 ish motor. I would expect more in a nearly 450" motor.

My personal opinion you can choose to disregard. Measure manifold pressure at WOT in the car all assembled and driving. If the manifold pressure is low leave it alone. If its excessive look at the air cleaner part of the system. If you are not happy at that point, change the cam. If you don't want to do that; just enjoy it.

I think a 250ish 260ish cam would make you in the range of 80hp more, but that assumes the heads keep up. I think they will be tapping out just north of 500. Making heading into the 580hp range requiring more head flow and of course more carb.

 

[emmaellisonn]

I'll try my best to keep my frustration to a minimum...

Took the cobra to a shop for some troubleshooting and an eventual dyno. Fixed the fuel issues and when they put it on the chassis dyno it produced way less numbers than I thought I was going to get based off what the engine builder advertised; oh and a wonderful leak coming out near the bellhousing.

It's a 445 stroker (built by Southern Automotive) with an estimated 500hp at the crank but only made 360hp on the dyno. Engine has 20 miles on it.

Quick specs:

Block: 390 cast iron (prepped and machined)
Crank: Eagle specialty
Rods: Eagle specialty h-beam comp
Pistons: Mahle HP - forged
Bearings: Clevite HP
Cam: Hydraulic flat tappet - comp cams
Timing chain: Comp cams double row
Heads: Edelbrock performer #60069
Intake: Blue Thunder aluminum 1x4
Carb: Quick Fuel 750
Compression 10.2 - 1
MSD distributor and box

If I recall correctly, tech at the shop said it was adjusted to 35 degrees at 3k rpms. Need to double check.

I really don't know what to do at this point, or if I need to do anything. Maybe I had unrealistic expectations?

Thank you in advance!

You Need to what can cause cobra's poor engine performance....

You may know this but I must say, old spark plugs or clogs in the system can cause a rough running engine, as can improper octane in the gasoline or a low battery. Like the other issues, mentioned-up simple tune-up could be all it through-running rough running the engine.

If you want to restore your engine performance follow the below points thoroughly.....

1. Ensure good compression.
2. Use synthetic lubricants
3. Check your ignition
4. Implement a cold air intake
5. Insta all larger throttle bodies and injectors.
6. Replace your exhaust manifold with real headers.
7. Use Forced Induction (aka Power Adder)
8. Most Importantly, maintain your vehicle. For more info, please view this- Used Engines Inc Blog - Latest News and Articles

 

[railroad]

IT'S GETTING DEEP !

 

[phils88gt]

IT'S GETTING DEEP !

What just happened?

 

[rich grsc]

What just happened?

Nothing really..Just comments made that don't really have anything related to the OP questions concerning a new engine?

• Ensure good compression.
• Use synthetic lubricants
• Check your ignition
• Implement a cold air intake
• Insta all larger throttle bodies and injectors.
• Replace your exhaust manifold with real headers.
• Use Forced Induction (aka Power Adder)
• Most Importantly, maintain your vehicle. For more info, please view this-

 

[JoshW]

I am excited to see you have a hyd roller rather than a flat tappet. Cam specs look good to me.
Here is a filter lid I use on a low hooded Mustang. I am pleased with it.

K&N XStream® Air Flow Assemblies, Filters, and Filter Tops

Factory direct K&N replacement air filters, air intakes, oil filters & cabin filters. KNFilters.com - the official site for performance filtration products.

www.knfilters.com

I think a good tune on the ign timing, Air fuel/ carb will wake up that engine.
Any chance you know whether they degreed the cam?

Finally got it home and they did a fantastic job tuning it. She runs great although I've run into another issue: hard to turn over when it's hot. I'll have to start a new thread for that one...
Not sure if they degreed the cam either.

 

[Gordon Levy]

Hard to turn over is either too much timing or a battery power issue

 

[JoshW]

Here is a dirty little secret about buying a new carb. Go on eBay and search for say, “850 Holley double pumper refurbished”. You will pay roughly 50 cents on the dollar. Any returns Holley gets, they dismantle, clean, reset to factory specs, and sell on eBay as factory refurbished. Looks new because it is. I’d go 850 myself. Around town you will only be opening the front barrels. Full wide open when you want full power, that 850 will shine. NASCAR uses 15x3 air cleaners because they support the power they make. If it doesn’t fit, get a extra low dropped bottom air cleaner. Race shops have them. Covers the carb almost entirely.

Huh. Definitely did not know that about refurbished Holley carbs. That is definitely a dirty little secret lol. Thanks for the tip and someone else recommended an 850 too. But then again someone else also recommended converting to EFI. With so many choices it's making my head spin...

 

[JoshW]

That's part of your problem. That's not much cam in a 440" motor. I would expect mid 230s intake and mid 240s exhaust in a 400 ish motor. I would expect more in a nearly 450" motor.

My personal opinion you can choose to disregard. Measure manifold pressure at WOT in the car all assembled and driving. If the manifold pressure is low leave it alone. If its excessive look at the air cleaner part of the system. If you are not happy at that point, change the cam. If you don't want to do that; just enjoy it.

I think a 250ish 260ish cam would make you in the range of 80hp more, but that assumes the heads keep up. I think they will be tapping out just north of 500. Making heading into the 580hp range requiring more head flow and of course more carb.

You had me at 580hp lol. I think the responsible thing to do is just wait till after the motor is properly broken in since it seems to be doing much better after the last adjustments. Thank you!

 

[JoshW]

Hard to turn over is either too much timing or a battery power issue

I told a buddy about the issue and he said to check the grounds. The shop did find that the one of the grounds to the frame was bolted over the powder coating, but did not check the ground from the block. That'll by my next check. Battery is a new 800CCA Optima.

 

[jperickson2001]

I had issues with starting till I got a Powermaster starter from summit racing. Stick starters turn too slow. These things a mad. Each starter comes with its own dyno sheet.

 

[JoshW]

I had issues with starting till I got a Powermaster starter from summit racing. Stick starters turn too slow. These things a mad. Each starter comes with its own dyno sheet.

Gotcha. Currently running a Powermaster 9606. I'll check the dyno sheet too. Thanks!

 

[langsbr]

That cam seems waay too small for a 445. I know a windsor doesn't compare directly to an FE, but my buddy and I built a 436 windsor with a 260/268 cam and AFR 225s. It made over 500 RWHP on motor. It's not surprising this makes under 400whp with that baby cam, but it probably has perfect driving manners and pretty good low end torque. Swap that cam and pick up 50-75whp.

 

[JoshW]

Forgive me since I’m new to engine building but if I swap the cam, would I need to change anything else with the motor? Since the motor hasn’t been broken in yet, (has 140 miles on it) I’d assume I would need to wait till everything is settled?
Thanks for your input too!

 

[phils88gt]

The break in on a roller cam really doesn't matter. Typically with a flat tappet you keep each lifter with the lobe it was mated with as best practice.

As far as cam swapping on any motor. You would need to check the following:

Are the installed valves springs stiff enough for the new cam?

Is there enough space between the valve retainer and the valve seal? ( if lift changes )

Is there adequate piston to valve clearance?

is the pushrod correct length? ( assuming the base circle stays the same it should be fine )

 

[JoshW]

Gotcha. I wish I could pay a shop to teach me how to do this. Like, I’ll pay for the labor, but let me do it with you so I can learn. I asked a shop if I could do this in the past and it was a hard no. 😑

 

[phils88gt]

Gotta find some car guys in your neighborhood if you bring pizza they will usually help you do it.

While sometimes it might seem like sorcery the stereotypical pushrod engine is basically all the same be it a Buick nailhead for a Big block Ford. I have never built an FE but would not hesitate to do so. In spirit it's all the same and has all the same problems any other pushrod motor has.

Each motor has unique challenges but principally they are all the same. More technologically advanced engines like the 4.6L or 5.0 4v have much more complex assembly but the same limits basically apply.

When talking camshafts the problems for all engines are the same and fitment is always the issue.

If the Lift increases one must look at all things that are lifted and ensure they can move that far. Hence the valve retainer comment. Piston to valve clearance is also a concern since the piston is the thing the valve is lifted toward.

A change in duration chances the timing in which valve is nearest the piston. It never changes the gross lift but it does change the time relationship. Adding duration can certainly create a interference problem.

Pushrod length sets the geometry of the rockers travel on the valve tip. This typically stays constant unless you change the cam base circle diameter or the heads themselves. The change in the heads may move the relative position of the parts around changing your rocker setup.

That said I can't tell you for sure you can add 20deg of cam and not have a problem. But it also may require no changes at all. That is where specific FE knowledge would help. Primarily what does the piston look like in a stroker that size? Usually stroker motors have dished pistons to keep compression reasonable. The more dish up there the more piston clearance you should have. That does somewhat depend on the shape of that dish so just a dish top does not make ample cam clearance but it might.

Phil

 

[phileas_fogg]

Have you driven the car with this particular cam in the engine? If not, I recommend you do. You may find out your current cam puts out plenty of power for your current taste. Also, I'd get the car running smoothly before introducing yet another variable to any perceived performance issues.


John

 

[JoshW]

Gotta find some car guys in your neighborhood if you bring pizza they will usually help you do it.

While sometimes it might seem like sorcery the stereotypical pushrod engine is basically all the same be it a Buick nailhead for a Big block Ford. I have never built an FE but would not hesitate to do so. In spirit it's all the same and has all the same problems any other pushrod motor has.

Each motor has unique challenges but principally they are all the same. More technologically advanced engines like the 4.6L or 5.0 4v have much more complex assembly but the same limits basically apply.

When talking camshafts the problems for all engines are the same and fitment is always the issue.

If the Lift increases one must look at all things that are lifted and ensure they can move that far. Hence the valve retainer comment. Piston to valve clearance is also a concern since the piston is the thing the valve is lifted toward.

A change in duration chances the timing in which valve is nearest the piston. I never changes the gross lift but I'd does change the time relationship. Adding duration can certainly create a interference problem.

Pushrod length sets the geometry of the rockers travel on the valve tip. This typically stays constant unless you change the cam base circle diameter or the heads themselves. The change in the heads may move the relative position of the parts around changing your rocker setup.

That said I can't tell you for sure you can add 20deg of cam and not have a problem. But it also may require no changes at all. That is where specific FE knowledge would help. Primarily what does the piston look like in a stroker that size. Usually stroker motors have dished pistons to keep compression reasonable. The more dish up there the more piston clearance you should have. That does somewhat depend on the shape of that dish so just a dish top does not make ample cam clearance but it might.

Phil

Phil,

Everything you just mentioned sounds like sorcery to me lol. I get the gist of it more or less though. My biggest fear is tearing into something and causing harm to the motor due to my lack of knowledge. Ha, I have no problem diving head first into something that's for sure.

Just joined one of the local cobra clubs in KY so I'm hoping to link up with someone in the area that is familiar with FE motors. I'll gladly bribe someone with pizza and beer!