PDA

View Full Version : roller rockers


el-camino
10-30-2005, 05:05 AM
i´m on the search for roller rockers for my new Dart Iron Eagle Platinum heads.
here are the specs:

Iron Eagle
200 cc
Cast Iron
64cc
2.05/1.60"
Street performance and restricted Oval Track 6000 rpm, 327/350 ci
http://www.dartheads.com/manager/uploads/Tech%20-%20200%20IRON%20SBC.pdf

camshaft is from Comp cams XE274
http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=12-246-3

now i have the choice:
1.52 ratio or 1.6 ratio
what is the better ratio for my combination :question:

cutlasskid
11-03-2005, 06:52 PM
if you had the rockers first they would have built the cam around the ratios you had. most of the time you dont want the same ratio on intake and exhaust and i have not seen them sell half a set of each ratio. it also depends on the piston to valve clearance you have.

TravisB
11-04-2005, 08:00 AM
I would call comp!

Y-TRY
11-04-2005, 12:48 PM
Yeah, call Comp.

Cutlasskid is right: Using longer rockers is a band-aid fix for a wrong cam. If you want more lift, order a cam with more lift. There is no mechanical advantage to having small lobes and large ratio rockers, in most cases. If you have the room, piston-to-valve, then go for the 1.6's. Lift is good.

But the same rule applies to the other statement about different ratios for intake/exhaust. There is no reason to alternate if you have the right cam in the first place. If you feel the exhaust is restrictive then get a split-duration cam and you won't need different rocker ratios. That's why they are sold in sets of 16. They figure people can order a cam that meets the needs for NET lift. Poeple experiment with rocker ratios to alter the lift without changing the cam. The change in duration is negligable.

Good combo, though. Sounds fun.

69MyWay
11-04-2005, 12:55 PM
Off topic I know...but.

I can't help but giggle now when I hear or see roller rockers. Ran into a very drunk lady at the Kissimme, FL cruise in last weekend. She walked up to my corvette and asked me if I had.

Rocky Rollers

Anyway, a little alcohol and just enough knowledge to be dangerous!

Okay...back on topic now.