A while ago I read an article (I think it was Chevy High Performance) where they featured a '92 Z28 with the LB9/700r4/2.73 gear posi combination.

They did some minor mods to the car to try and increase the performance. One of the things that they did was install some 1.6 ratio rocker arms. At the time they didn't know that since the car had the LB9/700r4 combo that it had the small factory cam, not the cam that the '92 G92 cars got.

They did a 3 angle valve job on the heads (stayed with the stock sized valves), installed a TPIS chip, throttle body airfoil, 3.73 gear alburn posi, headers, high flow cat, and cat back exhaust if I remember correctly. Other than that the car was stock.

Is there any real performance gain by installing 1.6 rocker arms in a stock engine?

http://www.summitracing.com/parts/CCA-1418-16/

 

On a dyno they will give you about 5hp to 10 hp and they add about .30 to your cam lift. I just added a set to my LB9 305 peanut cam 88 IROC in an attempt to get some extra hp out of this pig slow motor.

Honestly, do not expect any et in the 1/4 mile by themself alone. It takes about 15 to 20 hp to move a tenth or two in the quarter mile. However, they are a good cumulative modification that may help out your other mods.

After I installed mine it was very noticeable that my motor tached up in the rpm's alot faster and I gained about 100 rpm in the top end. But I also went full roller. I have not gone to the track yet to see if there was any et improvement but I am not really expecting any.

You can go full roller for a little bit more: http://www.summitracing.com/parts/SCC-SCP1036BL/

 

Thanks for the information. Yeah I have always been curious about that. It just sounded like a lot of work for a small gain in performance. I was thinking about installing a set in my car. Other than full exhaust the engine is all stock.

I just wish all the LB9/700r4 cars after '85 had the G92 style cam. I am sure they made more TPI/700r4 combinations than L98/700r4 or LB9/5-speed combinations. I guess it was to meet the fuel economy standards.

 

Actually, the install is easy. One of the guys on the board came over to my place and we did the install in about an hour. One of the easier mods to install compared to most.

 

where can you find NON roller 1.6 rocker arms

 

Self aligning or NON self aligning style rockers?

http://www.summitracing.com/search/P...eyword=rockers

 

well whichever rockers are on my 82 305... self aligning i guess???

 

I would say bad guess given SA rockers started in '87
Might pay to check type before ordering to avoid having to exchange them

 

what does self aligning mean? that the rocker isnt guided strait by the push rod?

 

Rocker has " ears' that center the rocker on the valve stem so it is " self aligning " and is not relying on the pushrod

 

If I put 1.6 roller rocker in my stock L98 would I need to change anything else for this mod?

 

Nope, you would really just be opening the valves to allow more air in and out. So it wouldn't hurt to have headers.

 

Ok sweet, I already have hooker headers and Im in the process of porting and polishing my TPI system

 

By the way will I need to worry about the valves hitting the pistons when swapping in 1.6 full rollers on my stock L98 or is it just bolt on and go?

 

Don't think piston clearance would be a problem, but retainer to guide/seal clearance is very tight on some of these engines. And on the earlier heads the pushrods may contact the bottom of the slot and cause noise and problems.

 

I have a set of Scorpion 1.6 ratio rockers for sale if interested (they run $222ish on summit)

 

so your are saying that i may have a clearance issue with the seals and push rods with my heads since its a 1989 L98

 

Running a full roller rocker will also help.

Mine are Comp Cams (CC) Pro Magnum self aligning. I also changed to CC Chrome Moly (CM) rods as well. CC recommends this.

If you're running centre bolt value covers, you'll need self aligning rockers.