I have a set of Edelbrock E-TEC 200 SBC heads that the springs are rated at .575" lift max and I'm running a Comp Cams Hyd roller with .520" lift on the intake and .540" lift on the exhaust and was wondering if I install 1.6 roller rockers will the .540" lift exceed the factory .575" lift on the exhaust?THANKS
Will this cause to much cam lift ???'s
- Thread starter dickeymoore
- Start date
.539" with 1.5 rockers would put it at .575" with 1.6, so I'm guessing it'll probably be ok.
Finding 1.6 from 1.5 lift, multiply by 1.067... to get 1.5 from 1.6, divide by the same # (1.6 lift divided by 1.067).
Finding 1.6 from 1.5 lift, multiply by 1.067... to get 1.5 from 1.6, divide by the same # (1.6 lift divided by 1.067).
Take the cam lift of .520 and divide by 1.5 ratio. Small blocks are calculated at 1.5 for stock ratio unless noted otherwise.
.520/1.5= .347 This is your lift at the lobe. Multiply by new ratio 1.6= .555
Do the same on the exhaust
.540/1.5= .360 Multiply by 1.6= .576
However, most times springs are rated for coil bind rating, not necessarily spring pressure. So, you can use a .575 cam and have sufficient clearance for coil bind. Maybe not enough spring pressure at high rpm. Another thing you can try is that it was popular to put 1.6 on the intake and 1.5 on the exhaust and see a power gain.
.520/1.5= .347 This is your lift at the lobe. Multiply by new ratio 1.6= .555
Do the same on the exhaust
.540/1.5= .360 Multiply by 1.6= .576
However, most times springs are rated for coil bind rating, not necessarily spring pressure. So, you can use a .575 cam and have sufficient clearance for coil bind. Maybe not enough spring pressure at high rpm. Another thing you can try is that it was popular to put 1.6 on the intake and 1.5 on the exhaust and see a power gain.
So if the MAX valve lift on my Edelbrock E-TEC 200 heads are .575" lift will It be OK to use the 1.6 roller rockers which will make the lift on my cam be .576" lift?
If your springs were installed to the proper spring install hight and your coil bind is no less than .060 you should be ok.
I assumed you had the springs called out for by the cam. Not to say yours are wrong but the cam calls out for certain seat pressures and lift pressures as mentioned by Bracketchevy and a spring install hight to achieve it. It's far from being just max lift. Why do you want to put 1.6's on the exhaust?
The engine has been running great for over three years now with the same cam and heads but the heads have 1.5 stamped roller rockers and i was thinking of swapping to 1.6 full roller rockers or should i go with 1.5 full roller rockers
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