NCRS Standards

[Duke W.]

Re: NCRS Standards

You can still buy a clone Duntov cam from FM Speed Pro as far as I know, but I still recommend the LT-1 cam to replace Duntov cam applications on any engine with 461 heads, which would include the '61 FI engines.

Duke

[Chuck R.]

Re: Aw...Chuckster...

I thru da sope bux in da wood stoov Chuck I git all huperventulated an stuff jest thinkin about it

So with that said, do you know where I can pick up an LT-2 cam Chuck?

Chuckster

[Michael H.]

Re: LT1 Cam???

Duke, yer kidding, right? It's me, Mikey, Mr. Stock and original! Why in the world would I want one of those wimpy LT1 cams in my 63? I want my car to be quick and sound healthy. That's why I choose the correct 097 cam.

[Mike McKown]

!

If I had gears in my car like you do, (3.08 axle, 2.20 first gear) I might recommend the Lt-1 cam also. Problem is, these cars weren't designed to have these kind of gears and some of these people listening to you don't know the difference. If you're gonna' use the gears Chevrolet said to use, everything is A-OK with the 30-30. The Lt-1 has a boring performance curve to it, anyway you slice it. When the 30-30 comes on, it is like somebody kicked you in the butt at about 3700. The LT-1 will NOT do that.

These cars (C-2) will not run with a stock C5 Z-06 anyway, so why worry about performance? The best thing to do is to get them to run like they are supposed to.

Last time you and I exchanged information on this board, you mangled my name and told me to go take a shower. Wasn't too considerate of you. I didn't appreciate it but I'm not a thin skinned person. You just seem like you have a bad case of tunnel vision to me, even though I know you know your stuff and have forgotten more than I will ever know about engines and their operating characteristics.

[Mike McKown]

Re: ! *NM*

[Michael H.]

Re: Unreal

I just reread your post and suggestion to install an LT1 cam in my 63 and I can't believe what I'm reading. You ARE serious! Remember me? I'm the guy that started all this anti LT1 cam business in pre 70's Corvettes a few months ago. Weren't we just discussing keeping these cars as stock and original as possible?

It's not about performance now. Those days are over for 60's Corvettes. A newer C5 could beat any stock 63 at Road America badly, and do it with the AC on. What's the point of trying to pick up a few horsepower and send it to those little skinny tires? Just buy a C4 or C5 if you want all that "today" stuff. Save what's left of our 60's cars the way we choose to remember them. You can pump the HP up in a 60's car but sooner or later, your going to pull up next to a new Corvette at a stoplight and it's going to be all over, no matter what kind of cam you put in it.

Why would anyone want to give away that pure Corvette sound of the old 097 or 30-30 cam? All of that LT1 cam stuff just makes absolutely no sense to me at all.

[Joe L.]

Re: My answer to that would be

Mike-----

Yes, GM did release oversize pistons for SHP (and, other) engines. However, these were SERVICE parts ONLY and were not used in PRODUCTION.

Also, depending upon what the definition of "low compression" is, GM DID release and use in PRODUCTION "low compression" pistons for SHP engines. The pistons used for 1971 LS-6, definitely described by GM as a SHP engine, produced a compression ratio of 9.0:1. Also, the pistons used for 1971-72 LT-1, also defined by GM as being of SHP status, produced a compression ratio of 9.0:1.

Some folks think that it takes "high compression" for an engine to "sound good". However, to my ear, I've never heard a Corvette engine that sounded better than a 1971 LS-6.

[Joe L.]

Re: NCRS Standards

Clem-----

That's sort of what I'm doing. I've got the original small block for my 1969 all rebuilt and stored away. And, if I ever get this job finished, I'll be installing my "ZL-1" to drive and play with. That work can proceed, now; yesterday, I finally got the windage tray that was supposed to be released about 2 years ago. It's a $300 (GM LIST) windage tray, but it IS a nice piece. Somewhat similar to a "full length" Milodon "Diamond Stripper", but actually quite a bit more sophisticated.

[Joe L.]

Re: NCRS Standards

Joe-----

Sometimes, folks have other goals in mind besides authentic RESTORATION. In many cases, folks no longer have the original engine in their car, anyway. Whether they do, or not, though, cams can be changed rather easily. So, you can install a cam for performance reasons, drive the car and enjoy it, and then change back to an original cam at some later time. No big deal, at all.

Personally, I NEVER, EVER advocate or recommend radical camshaft profiles for street engines. Usually, I would recommend nothing more radical than the "equivalent" of a stock SHP GM cam. For original SHP engines, I generally believe that a stock or reproduction original cam is the way to go.

For general performance Corvette engines, though, a lot can be achieved by changing a cam to a modern grind, especially a retrofit hydraulic roller. For the most part, the bottom end of these engines was never designed for SHP RPM range. But, with a modern camshaft profile one can achieve a lot more power and torque in the RPM range the bottom end of these engines was designed for. The "sound" of the engine will not be discernably changed if one sticks with a reasonable profile.

[Duke W.]

Re: LT1 Cam???

The LT-1 cam will make more top end power with about the same low end torque.

Being as how the effective overlap is about the same, you can't tell the difference in idle characteristics.

Duke

[Duke W.]

Re: Unreal

My philosophy is to maintain OE appearance, but make "under the covers" changes to improve performance/reliability because my car is for driving. So internal modifications like head pocket porting/port matching/multiangle valve seats, upgrading the connecting rods to something that is bulletproof, and replacing the Duntov cam with the LT-1 cam will improve overall engine performance/reliability without changing appearance or affecting the visceral quality like idle characteristics.

Same applies to the chassis. Modern seventy series speed rated radials, some subtle changes in alignment and hard bushings in the front anti-roll bar links improve performance without affecting overall driving quality or visual appearance.

Similar philosoply applies to the coachwork. Most restored Corvettes have better panel fit than St. Louis could have ever produced. Why would anyone restore a car to sixties quality levels?

In my case as an original SWC owner I lived with all the flaws through its first life. It's second life will not have them.

Duke

[Joe L.]

Re: LT1 Cam???

Duke-----

Also, the "30-30" camshaft, GM #3849346, was discontinued in December, 1971 and replaced by the GM #3972178. For that to have occurred that long ago, I'm sure that GM considered the 3972178 to be equal or better in every way. At that time, the 3849346 camshaft was only 7 years old and, at that stage in the life of a part, usually a supercession represents an upgrade rather than the result of parts "consolidation".

The GM #3736097 "Duntov" cam was never officially replaced by the 3972178, though. GM continued manufacturing and selling that cam until April, 1994 when it was discontinued without supercession.

The 3972178 was discontinued about 2 years ago. All of the above cams are available in reproduction from Crane, GMPP (Crane-manufactured), Federal-Mogul and others.

[Michael H.]

Re: Unreal

Duke,

That's fine for your car if that's what you want but many of the people that request info on the correct cam for their 65, never get it. Instead they get the same story about the LT1 cam. A few months ago, someone wrote and asked what the correct part number would be for the cam in his 65 365 HP car. You responded with an immediate rejection of the 3849346 and said that the cam that he wanted was the "new and improved" LT1 cam. The man didn't ask your opinion, just the correct part number. So, the NCRS, the National Corvette Restorers Society, recommended, without request, changing from the original configuration of his car. I hope he stuck with what he wanted originally and purchased the 3849346.

It's totally out of character for anyone on this board to automatically recommend a non stock non correct item. Or at least it should be. There are some items that should be upgraded as a safety issue for those that are going to drive their cars but I don't see that cam in the list. I do see you recommending it to people that don't even ask for information on it. If someone want's an opinion on their cam choices, that's another story and I agree with you giving as much info as you can but if they have "correct original" in mind for their restoration, then suggesting anything other than that is wrong. If someone wants to know how to modify something, then I agree that if someone here knows the answer, by all means, post it.

This issue has gone far beyond which cam makes more torque. I don't even care and I think a lot of other people feel the same way. It's not about horsepower now. It's restoration and preservation. At least it is here in this organization so when someone asks what the part number is for the 65 FI cam, the answer should be 3949346, period. No recommendations, no unrequested advice. I agree that if something was a bad design or created problems, a more current GM replacement could be recommended but the cams that are being discussed are excellent choices for the application.

We've all changed and modified our cars over the years in one way or the other but we have to remember that most of the people that come here want to restore their cars back to original for whatever reason. It's their choice and I think we should respect that.

Michael

[Kenneth G.]

Re: NCRS Standards

Joe,

when you eventually get the ZL1 done any chance youll take it to the track for some 1/4 mile fun? Just curious about what eta's you think it will/might do.

Kenny #31871

[Joe C.]

Re: originality versus practicality

Warren:

Engine overbore is simply a maintenance issue, and cannot be avoided, unless folks want to re-sleeve their bores upon every engine rebuild. But a CAMSHAFT change is strictly voluntary. The 30-30 cam is available in the aftermarket, so THAT is not the issue. Further, there are folks who sometimes lower the compression in the (often) mistaken belief that this is necessary with today's gasoline. We MUST educate folks that this is not necessary with SHP smallblocks, and in this, and many other regards, I know that Duke is doing a GREAT job. My only fear is that before long, with this persistent selling of the LT1 most smallblock Corvettes of the muscle car era will end up as generic/cloned shadows of their former selves.

Joe