NTChrist

Howdy all,
I've just bought a non cc HEI distributor that has been freshly rebuilt.
It'll be run with a stock '95 LT1 roller cam in a roller 350 block (1 piece seal) with a carb and no computer.
The guy who rebuilt the distributor says that the gear is "stock" for it's application (2 piece rear seals, flat tappet cam). The gear is light grey in colour, and not shiny.
I believe that I will need to replace it with a "melonized" distributor gear, correct? If I'm mistaken, please correct me.
Now for my q: Is GM the only source for this gear? $31 USD plus shipping sounds a little extravagant, seeing as it's a factory gear. PACE parts melonized gear
TIA

SinthetikIroc

iTrader: (1)

go to the junkyard and swipe one out of a roller cammed motor.

RB83L69

The one in a roller cam motor will probably not fit; it will most likely have the wrong inner diameter, since it's coming off of a completely different model of distributor.

Most likely, any stock gear will work fine. Factory type (street) roller cams are ground on a cast-iron core that's basically the same material as a flat-tappet cam blank.

Just FYI, I'm running the stock 83 L69 dist gear right now, on a Comp XR series cam. Seems to be working fine. Of course I only have a little less than 2 years and about 25,000 miles on it; so who knows what the long-term longevity might be.

NTChrist

Good point. That hadn't occured to me.

Any more votes for "stick with the grey matte gear you have now?"

NTChrist

Off-topic...

I'd just like to say: "Whoa, a semi-colon used correctly on-line."

RB83L69

This evil cannot be tolerated! Shoot him! String him up!!!! Extract his whole colon!!!!


EEEwwwwww

NTChrist

Any more opinions?

Twilightoptics

On Distributor Gears:

The roller cam is hardened steel, so they use a soft cam gear. Aftermarket usually uses bronze, and sometimes even plastic, and they need to be replaced fairly often. Gm however used a different metal(think its melanized steel) anyway, the gm roller distributor gear should work on any cam with no problems.. Some roller cam manufacturers now make the cam out of two different metals. This way the lobes are billet and the gear is cast. Lots of different things out there.

If early type distributor is used on a Roller Cam motor you will need the GM 104560413 distributor gear.

RB83L69

Factory roller cams and street hydraulic rollers are not hardened steel. Only real race rollers are. The others are cast iron. The billet race rollers do require a softer gear; a regular GM one, melonized or not, will eat the gear off of a billet cam.

Here's a pic I posted this morning, of a Comp XR hydraulic roller sitting next to the OE flat-tappet cam out of my 83 L69. Note the material and production techniques that are evident on both of them.

https://www.thirdgen.org/techbb2/sho...hreadid=174394

This whole thing about factory rollers needing special gears is a myth. It's right on up there with the one about waking up in a bathtub full of ice water with one kidney missing.

NTChrist

Alright, sounds like I will stick with the stock gear.

One last bump, in case there are more opinions...

Twilightoptics

So, why does GM change gears between the two cams then?

And are we coming to a complete FACT that you can use any dizzy with any stock camshaft?

RB83L69

I'm not within GM, so I can't answer factually for them; but i suspect that they changed gears for some completely other reason (since as we know they did it at some other time) that has nothing to do with whether the lifters are of the one design or the other.

Kind of like the 2-piece to 1-piece rear main seal... they did not do it for any reason that has to do with sealing; they did it because it made the engines cheaper to assemble. My guess, based on my experience, is that it's worth a good ½ hour of labor off of every engine..... if their fully-absorbed labor cost is $60/hr, and they build 1,000,000 of those a year, and it saves ½ hr each, that's $30,000,000 directly into the bank account every single year. That sort of thing is much more important to people who run companies than piddly little people like us that want to swap old and new stuff around in 20-year-old cars.

Twilightoptics

Well I've got an old points style dizzy with upgraded electronic points...... can I use it on my stock '87 305 LB9 roller cam.... or even the stock LT1 cam I'd like to use?

Vader

Yeah - Save some of the sphincter, or there won't be anything left. :rockon:

A sintered gear should work fine. On the L99, LT1, and LT4, thers is no choice for the driven gear, but lots of choices for aftermarket roller cams. Then again, the gear only drives the oil pump stub shaft, so I guess it isn't really that important. I don't have as many miles on my "mismatch" as RB, but two Comp cams and almost 8,000 miles later it's still holding oil pressure, so I'm guessing it's at least turning.