Mixed roller rockers

[likwidsukr]

Why would someone run mixed ratio roller rockers. There are some on ebay for sale with mixed ratio :hammer2: :cool:
:hammer2: set of 8 Pt# 27757-16 1.6 ratio and 8 Pt# 27759-16 1.65 ratio rockers :hammer2:

[UBFJ #454]

What heads do you think they came off? :D
Do you think they came off Stock Heads? :D :D
Could they have had some 'Special Work' done on them? :D :D :D

[FoMoCo]

I ran mix rockers on my first motor. 429 BBF. Since Fords have poor exhaust port flow I ran 1.7 ratio on the intake and 1.8 on the exhaust. I was running a solid roller cam that had the same intake and exhaust lift so the bigger ratio helped.

[Moneypitt]

Some builders/users "crutch" the weak point of a combination by increasing the ratio on the rockers to increase the action of the cam. This could be done to enhance a poor exhaust port design, or to assist scavaging by a mismatched set of headers. There are several reasons why someone would do this, but most of them come back to trying to "fix" something in the set up that isn't quite right. I know crane makes 1.8:1 rockers to assist BBCs breathing. Also, sometime the engine has been transplanted into something it wasn't built to be in,(weight/ gear/load) and the additional rocker ratio may step it into the new home a little better...............MP

[UBFJ #454]

Some builders of what some would call 'Exotic' Motors use more than two different rocker ratios in a motor ... Not to "Fix" anything, but rather, to Optimize Everything As Best As Can Be Done Within the Constraints of even the 'Best' Aftermarket Parts and Budgets.

[FOURQ]

maybe the same reason we run diff. piston compression heights in our nitro funny car ... to get the most out of it

[UBFJ #454]

Same Way Of Thinking.

[clownpuncher]

maybe the same reason we run diff. piston compression heights in our nitro funny car ... to get the most out of it
Don't ever lose that avatar :wink:

[dave186]

ive heard of some of the 5.0 guys running a 1.6/1.7 combo when running boost. supposed to help the exhaust out since the intake side has the help of the charger/turbo.
and that is a nice avatar 4Q :rollside:

[likwidsukr]

thanks guys i was a little confused but I am clear now. At least it makes since anyways. Crane golds at $100.00 Not too bad a price.......Yet

[Squirtin Thunder]

Usually that combo is used on SBC. I used it quite offen back in the '80s on the LT1 350. It works great. Now with the BBF I would like to see that only with a strieght cut cam. BBF love abit more on the exhaust side.

[superdave013]

thanks guys i was a little confused but I am clear now. At least it makes since anyways. Crane golds at $100.00 Not too bad a price.......Yet
I'd buck up and get a new set. One of those suckers breaks the little needle bearings will go right to the oil pump. Don't ask me how I know.

[likwidsukr]

I'd buck up and get a new set. One of those suckers breaks the little needle bearings will go right to the oil pump. Don't ask me how I know.
Dave thanks i am getting new ones just could not think why people use diff ratios. Until now. :cool:

[Jet Hydro]

Dave thanks i am getting new ones :cool:
They brake too ;) Dont ask :D

[superdave013]

They brake too ;) Dont ask :D
yes they do. I'd stay away from Harland Sharps or anything like 'em. Look at the trunions. Get the biggest ones you can. Comp Cams makes a nice stout alum rocker that can be rebuilt.