1.65 rockers on a SBC? Pushrod clearance?

enkeivette

enkeivette

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Mar 30, 2008
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I have a set of AFR 195 heads with guide plates. Does anyone in here know if I'll be able to run 1.65 ratio rockers without having any sort of clearance issues?

Any other reasons not to use the 1.65 rockers as opposed to the 1.6 rockers?
 
Never heard of 1.65 ratio rockers. Most common for a old SB is 1.5 , 1.52 and 1.6 - next step up is 1.7 or so for the LS1....
 
Yeah, uncommon, that's why I'm worried about clearance. They also make 1.7s for a sbc, even more rare.
 
We build a lot of circle track engines and the ones that are restricted to a copression rule like 11:01 and 358 CID and flat tappet cam we will machine the cam tunnel to BBC and and with steel valves go with a 1.8 ratio and with 1.9 we have to to ti valves because with the valve acceleration and at the higher rpm there would be a good chance of floating the valves.

The bigger base circle cam makes for a more rounded lobe that will take the higher ratio rockers with out tearing the nose of the cam off.

The other rule of thumb is for every point of rocker you go up you can drop 2 or 3 degrees of seat and .050 numbers on the cam as you diong it with valve acceleration and droping the seat timing events will increase dynamic pressure making for much more torque and HP and it has shown to be a winning combination.

Basicly we are taking a gen 1 engine and making it run like the ls engines as they use big cam cores high rocker ratios and make dam good torque and power.
 
Do you think I'll damage my small base circle Comp Hyd Roller cam with the 1.65 rockers?
 
enkeivette said:
Do you think I'll damage my small base circle Comp Hyd Roller cam with the 1.65 rockers?
Click to expand...

I've been running 1.65 and 1.7 on my Dart 215, 227, and AFR 210.

I would think that the limitation would be springs and the H-roller. Most H-roller springs use a max of @ 145 pound seat. That is why HR are kind of limited to 6500 or less rpm because of valve float in our old heavy valved SBC's.

Higher ratio would induce valve float and even lower rpm.

You can yank the Hroller out and buy a set of Srollers and good spring and live happy ever after
 
When I bought my 97 SS, the previous owner had installed 1.65 Crower roller rockers on the LPE hydraulic roller. Seemed to work fine, but I swapped them to Pro magnum 1.6s when I did my cam swap for piston to valve clearance.
 
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