Roller Rockers in Stock

Charley Downing · 07-03-2008, 07:39 PM

I have been using jim's products for over two years in all our race cars ( sb olds and sb chevy) it is by far the best was to go NHRA stock racing with out breaking parts,

Jeff Lee · 07-04-2008, 11:02 AM

I can't imagine that a 6500 RPM stocker is considered "high" RPM. But high or not, it was with larger or more radical camshaft design that the car responded with quicker ET's and faster MPH's, with the limitation on upper RPM being placed on the small Autolite carb I ran. Now I guess if I were on the outside of the conversation listening in, I would maybe say "so Jeff Lee, I'l bet you never got that AMC 390 to run very well because obviously you don't have a handle on the valve train issues". Well, the best times were 10.500 @ 125.01 in D/S in what was "killer" air; in Arizona (which never see's air like the sea coast tracks). But typical would be a 10.62 @ 124.7 @ NHRA events.
So I guess that would lead me to "so your saying I need to lower the RPM and ET/MPH to save the parts"? Well tried that. All I can say is it went slower. And I guess for me that's a bitter pill to swallow.
Now I also have spoken to Vic Guillimo (I know, incorrect spelling). His 429 Ford, which is equally as fast but in D/SA, tells me he breaks rockers more frequently than even I did. Clark Holyrod came up with a substantially larger system which he markets to reduce or eliminate breakage. Aparently he, and his (many) customers along with Vic & I haven't been able to come up with the camshaft that will work in Stock that gives a 3-1 safety margin on rocker safety. Maybe the answer is a "pure Stock" cam?
Now if I had to guess at the one thing these racers mentioned above have in common is high compression ratio's on their NHRA blue-printed engines (429/396-375/427-425, etc.). Maybe that's part of the issue as well, I don't know. I just know they have issues, not just stupid old Jeff Lee.

Jeff Lee · 07-05-2008, 08:44 PM

Furthermore...

Chris Hill stated:
"The parts still broke with bearing steel. Then we changed the design of our valvetrain to lessen the impact loads, we could use the original Stainless steel material. The issue was not the material of the part or heat treatment, it was just a bad design".

Jeff ask's:
So you had failure with stainless rockers, developed a whizz-bang cryptonite rocker to no avail, then fixed the cam lobe and then the original stainless rocker stopped failing. Is this correct? So a better cam lobe solved the problem and therefore your confident that a standard Speed-Pro SBC stamped rocker available from AutoZone will get the job done on the lobe you and your crew developed under competition useage (burnouts. various loads, possible missed shifts, etc.)
So my big question is, what type of cam lobe are you testing against? Is this a NHRA Stocker lobe with approximately .450" lift (which I'm guessing may be an average) with duration and ramp designs that will allow the engine to be competitive? Or are you talking about a bracket-style, maybe even street / strip style cam lobe that is much less aggressive than the Stocker lobe?

View Poll Results: Should roller rockers be allowed on all stockers?
Yes	113	53.81%
No	97	46.19%
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07-03-2008, 07:39 PM	#1
Charley Downing Senior Member Join Date: Sep 2007 Posts: 762 Likes: 16 Liked 653 Times in 89 Posts	Re: Roller Rockers in Stock I have been using jim's products for over two years in all our race cars ( sb olds and sb chevy) it is by far the best was to go NHRA stock racing with out breaking parts,

07-04-2008, 11:02 AM	#2
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: Roller Rockers in Stock I can't imagine that a 6500 RPM stocker is considered "high" RPM. But high or not, it was with larger or more radical camshaft design that the car responded with quicker ET's and faster MPH's, with the limitation on upper RPM being placed on the small Autolite carb I ran. Now I guess if I were on the outside of the conversation listening in, I would maybe say "so Jeff Lee, I'l bet you never got that AMC 390 to run very well because obviously you don't have a handle on the valve train issues". Well, the best times were 10.500 @ 125.01 in D/S in what was "killer" air; in Arizona (which never see's air like the sea coast tracks). But typical would be a 10.62 @ 124.7 @ NHRA events. So I guess that would lead me to "so your saying I need to lower the RPM and ET/MPH to save the parts"? Well tried that. All I can say is it went slower. And I guess for me that's a bitter pill to swallow. Now I also have spoken to Vic Guillimo (I know, incorrect spelling). His 429 Ford, which is equally as fast but in D/SA, tells me he breaks rockers more frequently than even I did. Clark Holyrod came up with a substantially larger system which he markets to reduce or eliminate breakage. Aparently he, and his (many) customers along with Vic & I haven't been able to come up with the camshaft that will work in Stock that gives a 3-1 safety margin on rocker safety. Maybe the answer is a "pure Stock" cam? Now if I had to guess at the one thing these racers mentioned above have in common is high compression ratio's on their NHRA blue-printed engines (429/396-375/427-425, etc.). Maybe that's part of the issue as well, I don't know. I just know they have issues, not just stupid old Jeff Lee. __________________ Jeff Lee 7494 D/S '70 AMX Last edited by Jeff Lee; 07-04-2008 at 05:07 PM.

07-05-2008, 08:44 PM	#3
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: Roller Rockers in Stock Furthermore... Chris Hill stated: "The parts still broke with bearing steel. Then we changed the design of our valvetrain to lessen the impact loads, we could use the original Stainless steel material. The issue was not the material of the part or heat treatment, it was just a bad design". Jeff ask's: So you had failure with stainless rockers, developed a whizz-bang cryptonite rocker to no avail, then fixed the cam lobe and then the original stainless rocker stopped failing. Is this correct? So a better cam lobe solved the problem and therefore your confident that a standard Speed-Pro SBC stamped rocker available from AutoZone will get the job done on the lobe you and your crew developed under competition useage (burnouts. various loads, possible missed shifts, etc.) So my big question is, what type of cam lobe are you testing against? Is this a NHRA Stocker lobe with approximately .450" lift (which I'm guessing may be an average) with duration and ramp designs that will allow the engine to be competitive? Or are you talking about a bracket-style, maybe even street / strip style cam lobe that is much less aggressive than the Stocker lobe? __________________ Jeff Lee 7494 D/S '70 AMX