Well Written Restorer Article

[Joe C.]

Did the owners of the 2 Corvettes with the Special 300 HP camshaft decide to leave their engines as-is, or re-install an original design cam?

How is it possible that a solid lifter Corvette passed a PV with a hydraulic tappet camshaft installed?

[Mike M.]

Re: Well Written Restorer Article

joe: the cam/lifters in my 57 250 HP engine are hydraulic. regards,mike

[Stuart F.]

Re: Well Written Restorer Article

Joe;

I think that was one of their goals.

That was a very well written article and the entire project was really amazing. I commend each of the participants. They have really raised the bar for the rest of us backyard mechanics and hobbyists. The entire issue is extremely well done. Anything I have to read more than once I place a high value on.

Stu Fox

[Timothy B.]

Re: Well Written Restorer Article

That is a very nice article and it sounds like Duke was some what dissapointed with the results. Also a great Corvette Restorer magazine..

I would not try it, and I am curious if the owners will change back to the original camshafts.. I must admit, I have always wanted to install a 340hp engine in my 63, but the 300hp engine runs good on the street..

[Mike M.]

Re: Well Written Restorer Article

duke's cam will remain in my 57 till the ground hogs deliver my mail. mike

[Stuart F.]

Re: Well Written Restorer Article

Now THAT is a ringing endorcement!! (or is it Gabriel's horn?)

Stu Fox

[Joe C.]

Re: Well Written Restorer Article

That is a very nice article and it sounds like Duke was some what dissapointed with the results. Also a great Corvette Restorer magazine..

I would not try it, and I am curious if the owners will change back to the original camshafts.. I must admit, I have always wanted to install a 340hp engine in my 63, but the 300hp engine runs good on the street..

Not with all three builds.........just both of the special 300 HP builds. Pumping losses are not insignificant and should have been taken into account in the overall design.

The McCagh special was "inconclusive", and from the results shown for that build, it looks as if it is possible that the cam did not do any harm.

[Jerry G.]

Re: Well Written Restorer Article

Very well written. I commend you folks for your work. I run a vintage FI race car and no one is doing cam research on our old lumps. Those of us trying to get the performance from a 327 with 461 heads have few choices. I understand. Cam manufacturers are in this to make money and there just aren't that many old Corvettes out there that want anything but "original". I appreciate the ground that Duke and the others have broken and I would gladly volunteer my race motor for testing a cam Duke designed for my motor package and use.

[Gene M.]

Re: Well Written Restorer Article

............Those of us trying to get the performance from a 327 with 461 heads have few choices. I understand. Cam manufacturers are in this to make money ..................

Edelbrock has done a lot of the work for us. They offer cam and lifter kit #2102 that is very strong in an otherwise stock 327. And I do mean stock, exhaust and everything. Bottom end is stronger, even from a stop, mid range way better as well and top end. Idle is just as smooth as stock cam. And it is made in USA.

No, I don't have any computer analysis or dyno runs. Just good old seat of the pants feeling behind the wheel..........

[Duke W.]

Re: Well Written Restorer Article

Most aftermarket cams are designed along "racing cam" lines and there are hundreds of them out there, but little real difference between many of them.

This project had specific objectives to improve torque and power bandwidths of base engines without any visual or operational clues, which means low overlap had to be maintained. A "racing cam" (or even an OE SHP cam) was clearly not the answer as their idle behavior would immediately betray them.

For a racing engine with headers and open exhaust, a high overlap cam indexed along traditional lines is what's needed - a completely different animal. It's simply a matter of optimizing the duration to the engine's inlet and exhaust flow, operating bandwidth that is determined by the maximum engine speed you set and gear spacing and the lowest revs you will see in the lowest speed corners, and then selecting as aggressive dynamics as you can stand within whatever you choose as valvetrain durability criteria.

It's interesting that the two special cams, particularly the McCagh Special ended up being very similar to the 2006 LS7 cam adjusted for relative E/I ratio. That is, relatively short duration, low overlap, but indexed very late compared to traditional designs, and "tuned" to the specific E/I head flow ratio.

What I find surprising is that no one (except GM on modern small blocks) has apparently ever done this before, especially considering how long small blocks have been around and how many guys have been playing around with them for over 50 years.

But then I rarely run into anyone who understands the difference between a racing engine and a road engine.

Most guys choose cams because "it sounds good idling across the parking lot on cruise night".

Duke

[Joe C.]

Re: Well Written Restorer Article

Edelbrock has done a lot of the work for us. They offer cam and lifter kit #2102 that is very strong in an otherwise stock 327. And I do mean stock, exhaust and everything. Bottom end is stronger, even from a stop, mid range way better as well and top end. Idle is just as smooth as stock cam. And it is made in USA.

No, I don't have any computer analysis or dyno runs. Just good old seat of the pants feeling behind the wheel..........

There is only one way to do that................fast dynamics. That cannot all be done at the same time unless you are willing to sacrifice some reliability in return.
You never get nothing for nothing. Period.

[Gene M.]

Re: Well Written Restorer Article

There is only one way to do that................fast dynamics. That cannot all be done at the same time unless you are willing to sacrifice some reliability in return.
You never get nothing for nothing. Period.

I don't think you find the dynamics all that bad. Yes, open and close rate (Edelbrock 2102) are a bit faster than 300 hp stock cam. But certainly not like the profiles of "racing cams". It is designed as a street cam. And again yes there is most likely less life to them. But in all fairness more than I will need till the dirt covers the box.

The over all duration and duration at .050" are similar to stock cam for ramp up and down (not all that much greater). Overall duration at .050" is about 10 degrees longer (intake) and an asymmetric profile with added .022/.042" lift. Exhaust is even a bit longer duration accounting for the ram horns. Designs have progress a lot in 40 years. Edelbrock has done their homework on the 2102.

The real neat thing is you can not hear or feel any difference at idle from stock 327 300 hp cam till you start moving. The added power is felt thru out the rpm range from idle to 5500.

[Joe C.]

Re: Well Written Restorer Article

I don't think you find the dynamics all that bad. Yes, open and close rate (Edelbrock 2102) are a bit faster than 300 hp stock cam. But certainly not like the profiles of "racing cams". It is designed as a street cam. And again yes there is most likely less life to them. But in all fairness more than I will need till the dirt covers the box.

The over all duration and duration at .050" are similar to stock cam for ramp up and down (not all that much greater). Overall duration at .050" is about 10 degrees longer (intake) and an asymmetric profile with added .022/.042" lift. Exhaust is even a bit longer duration accounting for the ram horns. Designs have progress a lot in 40 years. Edelbrock has done their homework on the 2102.

The real neat thing is you can not hear or feel any difference at idle from stock 327 300 hp cam till you start moving. The added power is felt thru out the rpm range from idle to 5500.

Sounds familiar. Have you been plagiarizing my posts again?

Comps "Nostalgia Plus" series are the way to go in cars driven as infrequently as ours. They add considerable breadth to the torque curve, especially when combined with some judicious head work. This all adds up to vastly increased driving pleasure at the expense of a small amount of durability.

[Joe R.]

Re: Well Written Restorer Article

Edelbrock has done a lot of the work for us. They offer cam and lifter kit #2102 that is very strong in an otherwise stock 327. And I do mean stock, exhaust and everything. Bottom end is stronger, even from a stop, mid range way better as well and top end. Idle is just as smooth as stock cam. And it is made in USA.

No, I don't have any computer analysis or dyno runs. Just good old seat of the pants feeling behind the wheel..........

Hi Gene:

I have the Engine Analyzer simulation software. Out of curiosity, I looked in their library to see if they have the Edelbrock 2102 cam, and they do. So, I ran a couple simulations.

I already have the stock 327-300HP engine built in my EA library. This is the bone-stock 300 HP with the stock 929 cam, stock 462 heads, running through the stock Corvette exhaust (simulated as 500 CFM). So, my first comparison was to take this engine and simply swap in the 2102 cam.

The simulation showed nice gains above 4000 RPM, with only a small loss below 3000 RPM. This is what I would expect with a bit more duration and overlap compared to the stock 929 cam.

My second simulation was to see what happens when I substitute pocket ported 462 heads (using flow data from my heads) on a stock 300 HP that has the 2102 cam. The combination of the 2102 cam and the pocket ported heads really wakes up the engine above 4000 RPM, although there is still a slight loss below 3000 RPM.

So, for what it's worth, the EA simulations of the Edelbrock 2102 cam show a nice improvement at higher RPMs (especially with pocket ported heads), but they don't show an improvement at low RPM.

This is NOT intended to dispute your seat-of-the-pants assessment of the Edelbrock 2102 cam. It is just a simulation, and is only as good as the simulation model it uses. Real-world engines are more complicated than simulations, as Duke's article illustrates.

One thing that simulations may not capture very well is throttle response, which is a big component in the seat-of-the-pants assessment.

I recall from previous discussions that some of your cars have pocket ported heads. Is that the case with the engine that has the 2102 cam?

The EA software does not provide a simple way to generate electronic copies of the simulation plots. I was able to create some BAD copies by saving screen shots to Microsoft Paint and converting them to jpg format. Screen shots of my two simulations are attached, with apologies for the lousy resolution. I need to figure out a better way to generate electronic copies of the simulation plots. They look very nice in the native EA screen display.

[Gene M.]

Re: Well Written Restorer Article

Hi Gene:..............

One thing that simulations may not capture very well is throttle response, which is a big component in the seat-of-the-pants assessment.

I recall from previous discussions that some of your cars have pocket ported heads. Is that the case with the engine that has the 2102 cam? ..................

Hi Joe good to see you at Carlisle,

I have installations in 327's without any attention to the heads. True mine are pocket ported. But the others (friends in the chapter) are not ported at all.

The thing that the computer does not capture is the bottom end is so much stronger even with the longer lobe profile. The "seat of the pants" feeling is no exaggeration. All gearing on these cars is 3.36 or 3.55 pretty much typical 62's, 65's and 66. The idle is so dead stock sounding smooth. The last engine I installed it in was fresh with the 300 hp stock cam. So everything was new.

I repeat, Edelbrock has done their homework on this one.