Hi,

I have a 88 Firebird with an LB9 roller-cam engine and it has been fitted with a HEI dizzy - I have searched the part number (1112977) and it looks like the HEI was used in the '76 Camaro.

Thing is, I have read a lot of conflicting opinions as to whether or not the drivegear on these older HEI units is o.k for use with the FACTORY roller-cam.

As far as I can gather from what I have read, the FACTORY roller-cam is cast iron, as would be the '76 cam - so will the dizzy be o.k for use with my engine?

I really need to understand this - am I right about the FACTORY roller-cam being cast iron, or is it steel with iron gears or what??

As for aftermarket cams - are they ALL harder than the cast factory cams and do they ALL need a hardened drivegear?

Why are people talking about soft materials like bronze for use with hard aftermarket cams??

Most important question is what drivegear is suitable for my cam?

Any advice/ suggestions would be much appreciated.

Thanks.

 

I ran one in my spare motor for 7 months. Inspected it b4 i put it in the rebuilt motor and dident notice anything wrong with it.

 

Can anybody help with this query, sureley one of you 3thirdgen experts knows a bit about cams and drivegears?

I need to know what material the GEAR on the 88 LB9 FACTORY roller is made from and what HEI DRIVEGEAR will be suitable - and why.

Also, what is all the talk about using bronze gears with aftermarket cams - I thought they were supposed to be hard?

Can anybody help at all?

Thanks,

Mark.

 

Here is a paragraph from a Wayne Scraba HP book that might help your choices.Attachment 140011

 

I don't know if anyone else can read that, but I can't.

GM recommends a "melonized" gear for use with a factory roller cam. If you buy a replacement gear from GM, it will be melonized. The factory roller cams are a little harder than flat tappet, but not nearly as hard as billet (for which the bronze gears are made).

If you have your stock distributor, take the gear off of it and put it on your old HEI.

 

Just wanted to clear up one last point...

What material is the factory roller-cam in an '88 LB9 made of?

Is it cast or steel - or steel with a cast gear or what?

Thanks