[JoshW]

Its possible that its just not broke in yet. I wouldn't be pushing horsepower until you get 500+ miles on it. Once its fully seated you may get closer to what you are expecting.

Also, what is the air flow ratio. Would assume the dyno is providing that information through the curve. A rich carb can wash out the cylinders and prevent the rings from seating. Not trying to be dramatic...just factual.

I think you are nailed it on the head. Stopped by the shop last night to check out it and the techs said it's definitely running better (minus the oil leak) after the changes as well as some minor tweaks. They ran it again on the dyno to see any changes and it bumped another 9hp and 12tq. After that he felt pretty convinced that it was time to leave things the way they are since it's still being broken in and everything is starting to get seated. He literally said, "looks like the rings are starting to get settled." I feel happier now.

 

[Jim1855]

JoshW,
I can't directly speak to FEs but C.I. I can relate to.
What I've found is anywhere you have flow restrictions will show a reduction in hp/tqe.
Air cleaners are a big restriction. I run 14" x 3" drop base and would go to a 4" tall if I can. Not pretty but functional.
Headers. I'd guess that you could easily use free flowing 1-7/8" primary tubes. This is what I run with my 427. I've run 2", these were fun but just a bit too big for street use. Generally smaller tubes provide for torque, bigger help upper end HP
Carb I think you indicated a 750cfm carb. I would suspect that this is about right. I run a 780 double pumper and spin to 7,000. Works just fine. Smaller helps drivability, larger helps upper RPM and HP.
Heads Not sure what you have, seems to be reports in a fairly wide range. I would think that something in the 200 to 230 range would be good but FEs might be significantly different in requirements. I run AFR 225, these work well for my use, plenty of low end torque.
As you are finding there are many approaches and opinions to the problem. I've got a pretty good idea of what I like and want, but that might not be the configuration that works for you.
There's probably more but I have to skate for now.
Jim

 

[JoshW]

are you on the FE Power site? 445 FE’s with a hyd roller cams and the same parts your using are pulling 500hp…, but with a better exhaust system. I have a 428FE in my cobra with iron heads that have been ported and polished have the same valves that you have. I run a car to 282S solid lifter cam in it and 411 rear wheel horsepower @5950 rpm Jon

No and I didn't even know about it!! I don't have a hyd roller though; flat tappet. Thanks Jon!

 

[JoshW]

My engine builder says the farther you have the carburetor from the intake, the more power you will have. Put as many spacers as will fit under the hood as you can between the carb and the intake. Edelbrock performer air gap usually wins all the intake shootouts. Try one. Big power maker. Adding a larger carburetor will make better high rpm numbers. Large 15” K&N air filter will support 600hp. Small filters restrict power. My 454 Windsor Stroker (7.4 L) was engine dynoed at 486hp, 600TQ on an engine stand. Want to be quicker? Put a 3:73 - 4:11 rear ended in.

My engine builder says the farther you have the carburetor from the intake, the more power you will have. Put as many spacers as will fit under the hood as you can between the carb and the intake. Edelbrock performer air gap usually wins all the intake shootouts. Try one. Big power maker. Adding a larger carburetor will make better high rpm numbers. Large 15” K&N air filter will support 600hp. Small filters restrict power. My 454 Windsor Stroker (7.4 L) was engine dynoed at 486hp, 600TQ on an engine stand. Want to be quicker? Put a 3:73 - 4:11 rear ended in.

Got it! I definitely want to check out all those options. Is 750cfm too small you think? A friend recommended trying to jump up to 850cfm with a bit of tuning too.

 

[JoshW]

Thanks for getting back to us Josh. I did a dive into the internet looking for simular FE builds. I found those heads to flow 270cfm at 600 which is enough air for 500hp but only of there is enough cam.

That said with the motor making a good bit more torque than power the cam has to be small. Unfortunately if you want big power it take a good bit of cam to do it. More cam takes more spring and more valve train stability yields more rpm which requires more of all three. It's a vicious circle.

The 390s I found made about 410hp440tq but did so with those heads a roller cam of 620 lift / 240ish duration and 110lsa and less compression. These engines are smaller but this is flywheel power.

Experience tells me even pig rich blowing soot it will not make a 50hp difference. If it runs so bad it fowls plugs and they don't light power will of course suffer.

I'm not saying dont fix a bad tuneup but it would be unusual for it to be so rich you lose 50hp.

So, how small is that cam?

Phil

Hey Phil,

I should have the cam card today, fingers crossed!

 

[phils88gt]

Hey Phil,
I should have the cam card today, fingers crossed!

I don't think the larger carb will show anything at all. It's easy to check. You can measure the manifold pressure at WOT and see what you get. A very low number of a couple of inches is reasonable. Large numbers would be a restriction. If there is a restriction I would bet it's the air cleaner. You could run it without the aircleaner and that will tell you.

Phil

 

[rich grsc]

So the head you have are 170cc heads on 445cu in engine, and you wonder why it's not making big HP numbers? I run a 185 head on my 331, make a conservative 350 at the wheel. You're choking that engine to death in my opinion.

 

[waynehyde01]

Carb was I believe to be bolted on from the box, but it was adjusted just this afternoon. Also found fouled out plugs too!

If it is fouling out the plugs it may be simply quelching the combustion. That will knock your power way down, but your engine builder should have experienced this. So, that leads me to think your air cleaner is too restrictive and you simply are not getting sufficient air into the engine, especially with the drop off at higher rpm.

 

[bobl]

So the head you have are 170cc heads on 445cu in engine, and you wonder why it's not making big HP numbers? I run a 185 head on my 331, make a conservative 350 at the wheel. You're choking that engine to death in my opinion.

Don't let that port size fool you. As someone mentioned earlier the intake is part of the port on an FE. That head flows 270 cfm on the intake and 200 cfm exhaust. With the right cam that will easily support 500 HP.

 

[phils88gt]

Don't let that port size fool you. As someone mentioned earlier

That someone was me. The port length certainly has a bearing on the total volume. What we are looking at for power potential is cross section. Usually a larger port has more area at the mininum section. Port volume is a easy way to quantify two heads of the same architecture. The Windsor head runner is longer and would be bigger for a given section.

Flow numbers are also not everything. Kaase has some real interesting things to show there. Numbers are indicators.

I'm still betting on a small cam in there. The flat tappet almost always gives up duration and ramp rate to a roller. There are exceptions to everything but the average flat tappet has less under the curve with simular event timing.

Phil

 

[phils88gt]

Hey Phil,

I should have the cam card today, fingers crossed!

Well did it ever happen?

 

[JoshW]

Well did it ever happen?

It did! Sorry for the delay, just got out the other day actually.

 

[Gordon Levy]

OK, That's a Hydraulic roller, not huge but pretty decent. Performer RPM intake, the heads you have, 750 carb tuned with a good air cleaner and exhaust I could see close to 500hp. BUT, Header types, side pipe type, air cleaner and parasitic loss all will have a bearing on what you put to the ground. If you can turn it to anything close to 400rwhp on the dyno you are using you will have a very fast car.

 

[rich grsc]

Just looking at you original post,
"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."
That seems about right. Engine dyno has no alternator, water pump or PS pump drag. In the car all the parasitic drag will show up, that includes the total drive line losses. Loosing a 100+ hp is about right when all the losses are added up.

 

[JoshW]

OK, That's a Hydraulic roller, not huge but pretty decent. Performer RPM intake, the heads you have, 750 carb tuned with a good air cleaner and exhaust I could see close to 500hp. BUT, Header types, side pipe type, air cleaner and parasitic loss all will have a bearing on what you put to the ground. If you can turn it to anything close to 400rwhp on the dyno you are using you will have a very fast car.

Gotcha, and thanks for the input! Any recommendations on air cleaner type?

 

[JoshW]

Just looking at you original post,
"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."
That seems about right. Engine dyno has no alternator, water pump or PS pump drag. In the car all the parasitic drag will show up, that includes the total drive line losses. Loosing a 100+ hp is about right when all the losses are added up.

Dang! Didn't realize there would be that much loss. Good to know especially for expectation management. Thank you!

 

[Gordon Levy]

14" round with enough of a drop base to clear the hood, 3" element and a filter top.

 

[JoshW]

14" round with enough of a drop base to clear the hood, 3" element and a filter top.

Got it, thanks!

 

[JKleiner]

Dang! Didn't realize there would be that much loss. Good to know especially for expectation management. Thank you!

The rule of thumb is generally 15-18% less on a chassis dyno and as Gordon said there are lots of variables that can affect it further.
Jeff

 

[railroad]

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?