i have read in some books that by changing the 4 corner exhaust rockers to 1.6 it would produce more power. so the question is this.
should i just keep 1.5's all the way around, or put 1.6's on the exhaust corners or 1.6's on all the exhaust?

tia,
RS

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1992 Camaro RS
Mods:
L30 Vortec heads, LT1 cam, SuperVictor intake, 454 TB, 65# injectors, 3” cowl hood,
Custom chip, 14x3 Open element w/ K filter, MSD 6a, MSD Coil, MSD wires, AFPR, 3-Row Al radiator, 180* t-stat, 1.5 roller rockers, Hooker 1 5/8 headers, 3" Hooker Aero Chamber cat-back, !Cat

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Underdog Racing

 

Underdogg,

I don't have an answer for your question but I noticed you have L31 heads. Did you have those milled down to 58cc? Where did you have it done if so and how much did it cost you. Or do you have a 350

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1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Custom Exhaust
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/26,000 miles

 

no, i have the L30 heads. same as the L31's but w/ a 58cc chamber.

 

I've never heard that before about the 4 corner rocker change. Does anybody have any dyno graphs showing this to be true?

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, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

oops, it a mistake... its the intake valves that get the 1.6's.

 

Every engine/cam combo is different and there is no real easy answer. for single profile cams with moderate/OEM heads, i'd put 1.6 on all exhaust valves. Reasoning is that the head intake flow numbers are usually better than the heads exhaust flow. Single profile cams just don't take that into consideration and 1.6's can help. Me, I would just change the cam.

When you get to high hp with GOOD heads and big and/or custom cams, fuel delivery/exhaust stuff can lead to different needs on a per-cylinder basis, which MAY demand different valve lift numbers, hence different rocker ratios. IMO, none of the motors in discussion here need to worry about that.

 

UnderdogRS,
Where did you get the L30 heads? Did you buy them new and if so how much did they cost?
Thanks,
~~~~~

 

he got them from Ebay.

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-Tas
'89 Formula WS-6
[soon to have Hooker 1-5/8" 50 state legal headers installed]

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

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EFI & Intake Options
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