Is there any ET advantage with a 55mm cam over a standard cam with same specs????
Thanks in advance

quote:

Originally posted by 00 DEAD ON:
Is there any ET advantage with a 55mm cam over a standard cam with same specs????
Thanks in advance

In theory....yes. Might be too small to accurately measure though.

The bigger base circle you run, the more stable the valve train will be. Very important in high RPM applications such as pro stock engines. Not sure how big they are running these days? I know that just a year ago 75mm was pretty normal for them.

Larger cam core will not break as easy or flex as much. Not sure how much flex is a problem but I have seen cams break and that makes a mess.

quote:

Originally posted by 00 DEAD ON:
Is there any ET advantage with a 55mm cam over a standard cam with same specs????
Thanks in advance

NO

No et change if specs are the same, but there are advantages. Already mentioned, more stable valve train. Bigger core allows for better lobe design. You can make the same power with a less aggressive lobe. Also as mentioned, less cam flex. That could be worth a little power depending on grind, spring pressures, and cylinder pressure......

But there really aren't any drawbacks to them except for initial cost..I went with a 55mm cam in my stuff since I was getting a new block anyway. My head guy wants to put one of Pat Musi's cams in my stuff next time around, and I'll just need to drill the oil feed holes and pull the roller bearins, install babbit...He runs a 60mm core in his smaller engines....cost for me is the same as the 55mm......

To go along with the 55mm cam discussion, can you fit a 4.75 stroke crank in a 10.2 block and a 55mm cam core without the two touching? Or does it require a raised cam block or a 4.625 stroke in the standard cam location block?

You can, I wouldn't.

quote:

Originally posted by NC3x58:
To go along with the 55mm cam discussion, can you fit a 4.75 stroke crank in a 10.2 block and a 55mm cam core without the two touching? Or does it require a raised cam block or a 4.625 stroke in the standard cam location block?

quote:

Originally posted by 00 DEAD ON:
Is there any ET advantage with a 55mm cam over a standard cam with same specs????
Thanks in advance

So as with many questions like this the answer is it really depends on the combo. If you are using a mild cam profiler with matching low pressure springs then no you would not see any difference on your time slip however once to move up to your typical TD/TS cams that many run these days with lifts at 1" or higher and spring pressures over 400 on the seat, you could, you would certainly see it on the dyno! Just changing push rods from 7/16", .185" to 1/2 or 5/8 is worth 10 to 15 HP, and that's with a raised cam block. In the big picture though, it's not one little thing that makes that much of a difference but when you string them together, that's when you will see it!

quote:

Originally posted by Lincoln:
You can, I wouldn't.

quote:

Originally posted by NC3x58:
To go along with the 55mm cam discussion, can you fit a 4.75 stroke crank in a 10.2 block and a 55mm cam core without the two touching? Or does it require a raised cam block or a 4.625 stroke in the standard cam location block?

Not without modifying a few rods! I think you can get a 53 mm cam to work in that combo though without touching the rods (Steel ones)

Watch the video. It's only a couple mins. They have 6.700 rods standard journal rods for BBC.

http://www.callies.com/catalog/product/ultra-xd/?

The answer is yes, bigger diameter cam cores have the latent potential for more engine output, in which torque and rpm are quantities of.

hp = torque x rpm / 5252

Latent potential for rpm is latent potential for torque is latent potential for engine output.

This one is Loaded with latent potential for rpm.

Everywhere you look, the most basic drag racing fundamental is overlooked. rpm is the limiter.

It's also what makes pushrod drag racing really interesting, at any level boundaries are tested.

Hence the reason I wouldn't.

quote:

Originally posted by TOP38:

quote:

Originally posted by Lincoln:
You can, I wouldn't.

quote:

Originally posted by NC3x58:
To go along with the 55mm cam discussion, can you fit a 4.75 stroke crank in a 10.2 block and a 55mm cam core without the two touching? Or does it require a raised cam block or a 4.625 stroke in the standard cam location block?

Not without modifying a few rods! I think you can get a 53 mm cam to work in that combo though without touching the rods (Steel ones)

The Callies XD rods have the clearance needed built into them. The video on the link I shared shows this. No need to grind the rods in this situation.

quote:

Originally posted by CHampshire:
The Callies XD rods have the clearance needed built into them. The video on the link I shared shows this. No need to grind the rods in this situation.

NOPE! They are just for SBC, not BBC's.

quote:

Originally posted by TOP38:

quote:

Originally posted by CHampshire:
The Callies XD rods have the clearance needed built into them. The video on the link I shared shows this. No need to grind the rods in this situation.

NOPE! They are just for SBC, not BBC's.

Take your pick. H beam or I beam?

quote:

Originally posted by TOP38:
[QUOTE]Originally posted by Lincoln:
You can, I wouldn't.

[QUOTE]Originally posted by NC3x58:

Not without modifying a few rods! I think you can get a 53 mm cam to work in that combo though without touching the rods (Steel ones)

we do 54mm cams all the time , with Oliver rods , no grinding required ..

quote:

Originally posted by Paul S/Q:

quote:

Originally posted by TOP38:
[QUOTE]Originally posted by Lincoln:
You can, I wouldn't.

[QUOTE]Originally posted by NC3x58:

Not without modifying a few rods! I think you can get a 53 mm cam to work in that combo though without touching the rods (Steel ones)

we do 54mm cams all the time , with Oliver rods , no grinding required ..

Paul, I would not put those POS rods in Ed's lawnmower ! And yes you can use a 53 mm cam with good rods in this combo.

Oliver had a really good product, then something happened, all on their end! where they would come apart with real low run counts, under 300! for normal BBC combo's. (The caps failed) This was 5 or so years ago. They denied everything! Maybe it's been fixed but they along with their rods can take long walk on a short pier!

This is simple. The bigger the diameter of the cam, the quicker you can make the ramps, hence more lift under the curve. This will make more HP down low and mid range. However in a drag race application where we are WFO, and the RPM drop isn’t that great, the gain won’t be as much. If you were road racing and the RPM drop was bigger and happened more often, then more HP under the curve would help regain max RPM quicker and might be a good improvement.