Hi, reading all this about cams I doubt on using the right cam for myself.

My 400 already has a edelbrock performer-plus cam with
204/In and 214/Ex at .050 lift and 112 lobe sep.
Intake 5 ATDC / 29 ABDC, Exhaust 44 BBDC / 10 BTDC.

I´m saving for a rebuild with some more performance,
my plan is a 0.020" head milling and a set of badger flat top
pistons 0.030" overbored to reach a CR of about 9.5 - 9.8.

This fits together with a edelbrock 600 cfm carburator and
performer intake, matching edelbrock valve springs, roller
rocker arms, MSD ignition and coil, no headers, 2.5" two-way short exhaust pipes with flowmaster muffler, C6 trans, no
pollution control and 95 octane fuel. The rear axle is 9" with
no idea of gear ratio.... I guess it´s a long gear `cause the
truck runs about 120 mph on the highway - remember here in
Germany we have no speed limit, he,he.

I wanna use the f100 as a daily driver, no towing and want
lots of torque in the 2.000 - 3.500 rpm range.

Danlee, please check these datas and estimate the torque
and give me your recommendation for the right cam.

Any thoughts from anybody ?


Thanks, Tom

 

Your compression ratio is to high for efficient operation on pump gas. Keep it down to around 9.0:1.

 

That is a lot of cam. It has 63 degrees overlap. You should have a high stall converter. I see no problem with detonation on 95 Octane pump gas. Small tube headers will help a lot.

I think you could get a more efficient motor with equal or better power, if you stick to 9.0:1 CR and use less cam. I don't like the specs on that Edelbrock cam. For all that duration and overlap, it doesn't have a lot of lift.

With a performance exhaust manifold the torque is: 348@2000 and peaks at 386@3000 RPM.
With small tube headers the torque is: 391@2K and peaks at 412@3500 RPM.

Compare these numbers with the numbers I generated in the other thread. That motor had only 8.5:1 CR, but the cams were better suited to the job.

BTW all those numbers were with headers.

 

Depending on where you are in Germany I understand the elevation can range from an average of 488m to 2962m.
So, using:
ABDC = 29
Compression = 9.8
That yields an effective compression of 9.4 or 201psi cranking compression at sea level.

Correction for 488m (1600ft) yields 9.01to1 or 193psi cranking compression.
Correction 2,962m (9718ft) yields 7.46to1 or 149psi cranking compression.

We run a Elevation corrected compress of 11.2 with and effective compression of 8.34 up to 9.0to1 using different cams all on 91 Octane with no issues. The rule of thumb we use is 200psi max cranking compression for 91 Octane.
So I think you should be fine compression wise if you are at 488m. If you are in the mountains then you may need a bit more compression to realize the performance you want.

I definately agree with Danlee on the cam choices

 

O.K. this is a lot of information and I still have to work up ...

Danlee, sorry to ask again but what do you mean with a
high stall converter, my technical vocabulary is not so big ?

So watching the numbers at the other thread the best
solution seems the 260HR. Is this a special cam, I did`nt find
it at the comp-cams website, only a 260H.

It´s a big difference between the 481 torque @ 2000 and the
348 or 391 torque you estimated for mine (thanks for doing that).

Do I understand you right to go with less milling (0.010") and chosing the 260HR ?

I guess I cannot fix headers because due to a independent front
suspension conversion the steering shaft nearly touches the left
manifold. There might be a matching header in this world but how
to find out ?

David, I live at 80m elevation not far from north sea, so the CR
should be fine ....

Thank you all

 

I believe the HR is the Hydraulic Roller cam. If you go to the compcams website, and look for all the cams listed for this engine, it should be listed near the bottom.

 

Hydraulic roller cams can open your valves faster and give more lift, so you get more volume of mixture into the cylinder in less time. They will idle smoother and give better gas mileage, because they have less overlap. However they are more expensive to buy and install, because there are extensive valve train modifications required.

You could use a 265DEH cam with little change to your valve train.
The figures for a 265DEH cam and exhaust manifolds and mufflers are 394 ft-lbs@2000 RPM and 408@3000 RPM.

A 255DEH gives 416@2000, 416@2500, and 415@3000 RPM.

Because your motor can't breathe you do better with a shorter duration cam. Long duration cams give up power at low RPM, to gain it at higher RPM, but without headers your motor can't breathe at high RPM, so you never get the cams potential power. That is one of the problems with the Edelbrock cam.

I don't know what kind of suspension you have, but I am using a Mustang II type with power rack and pinion steering. I have an Ididit steering column connected with Borgeson U-Joints to the steering. The u-joints allow the steering shaft to bend around the headers.

I am using Sanderson Block Hugging headers Model FC-3.

Try www.sandersonheaders.com.

A high stall converter is a torque converter that allows the motor to run unloaded until a higher RPM than a normal torque converter. The high stall converter is necessary when a motor has a long duration cam with a lot of overlap and low manifold vacuum at idle. I believe the Edelbrock cam falls into this category.

 

The high stall converters also slip more at cruise...

 

Bingo, I found the 260HR, I overlooked it .....

Danlee, I watched the Sanderson-website, a good link with
complete informations !

I use a Mustang II steering rack with a fat man crossmember
bought from sacramento vintage. I`ve cut the standard
steering shaft to length and created a short shaft between
two borgeson u-joints to connect to the rack.

Now looking at the FC2 or FC3 headers I guess they might
fit in this special location.

Once more you gave me important informations about which
cam to choose, you are very helpful !

In view of the extensive valve train modifications I´m tending
to the 255DEH, which shows good torque performance on
your dyno.

Now I have to check what else belongs to this cam as push rods,
lifters, rockerarms and valve springs...

Good info about the converter !

Thanks a lot, Danlee !

 

walkee,

If you install headers, you could use either a 265DEH cam or a 255DEH. You should not need a high stall torque converter with either of these cams. With small tube headers the torque is 432@2000 RPM and 420 @3500 RPM for the 265DEH. The 255 DEH gets 452@ 2000 RPM and 420@ 3500 RPM.

 

Well I guess that´s the way to go :

a 255DEH and FC2 or FC3 headers and keeping the standard
torque converter ....


Thanks again, Danlee !

Sometimes I´m thinking of moving to the USA for half a year
and get a development or training in V8-rebuilding .....
.... maybe in 20 years when I´m retired (only joking)