Hi all,
I have searched on the forum, and don't quite have the answer i'm looking for. I own an '89 IROC with a 305 / T5 transmission. According to the threads this has a hotter cam with the T5 than the standard cam in the '89.

My simple question is - with the bigger standard cam, am i at risk with any valve collision with these rockers below?

Summit has suggested the following product for my needs:

Scorpion Racing SCP1143
Specs: 1.6/1.5 SBC 3/8 .100 Offset Blue Race Series Rocker Arms Set of 16

Summit Racing Part Number:
SCC-SCP1143
UPC:
887753242815
Rocker Arm Mounting Style:
Stud
Self-Aligning:
No
Rocker Arm Ratio:
1.6, 1.5
Maximum Spring Diameter (in.):
1.650 in.
Rocker Arm Style:
Full roller
Stud Size:
3/8 in.
Rocker Arm Offset (Intake):
0.100 in.
Shims Included:
No
Rocker Arm Material:
Aluminum
Rocker Arm Body Style:
Standard
Rocker Arm Fasteners Included:
Yes
Slot Style:
Standard
Slot Width (in.):
0.634 in.
Rocker Arm Finish:
Blue anodized
Quantity:
Sold as a set of 16.
Rocker Arm Offset:
.100 in. intake, .000 in. exhaust

Thank you everyone.
Eddie

 

With the possible exception of the Canadian (export) model having a 1987-version 14088841 cam grind, it is more likely that the '89 in question would have been supplied as follows:

Automatic Trans - 10088155 - 179/194 Duration, .350/.384@1.5, .373/.410@1.6 109° LSA
Manual Trans - 10066049 - 207/213 Duration, .415/.430@1.5, .443/.459@1.6 117° LSA

The nearly 0.460" exhaust lift with the 10066049 cam under 1.6:1 rockers could be approaching interference if manufacturing tolerances and assembly variations were exactly wrong. Chances are that everything will clear on the valve and head side. It will be your responsibility to check interference.

The bigger concerns are the springs (if they are stock) and the aluminum construction of the rockers.

 

Thank you for your response. I do in fact have a Canadian model - does this change your advice or info above?

What are my concerns with the stock springs and aluminum construction of the rockers so I understand correctly. Reading between the lines, my guess is you are referring to my stock springs not compressing enough / and causing issues with the weaker aluminum rockers? Please clarify.

Thank you very much.
Eddie

 

On stock springs (85 pounders) there is probably no concern. The rockers will never see enough pressure to wear them out any faster. With better springs, aluminum can begin to reveal its weakness.

Regarding the Canadian (export) model, the cam profile can be different, and it should be more like the early TPI cam grinds. Either way, the clearance needs to be checked.

 

Thank you again Vader for your response.

 

And of all your choices for replacements, the Scorpion rockers are probably O.K. Motley Crue rockers can create much greater challenges, and White Snake rockers should be completely out.

Just sayin'...

 

I have heard that the KISS rockers can be obnoxiously loud.