74 302 Rocker Arm Ratio

[savage]

What is the stock Rocker Arm Ratio on 302?I want to go to a different stlye of roller on my steel heades they have been reworked with heavy springs for the new cam,was woundering what ratio you guys are using,whats the defference between 1.6 and 1.7?

 

[ENDLIFE]

I run 1.6 rollers, and I think stock could be in the neighborhood of 1.5. As for the difference between 1.6 and 1.7, it's just that simple, as your rockers are going to open the valve 1.6 or 1.7 times your cams maximum lift. However, be aware if your running a cam with a generous amount of lift it is wise to check piston clearance using a special spring, so if you value your engine this is a step that shouldn't be skipped if your going big.

 

[baddad457]

The difference is .030 at the valve. You should also check for coil bind in the springs due to the increased lift.

 

[bmc69]

The difference is .030 at the valve. You should also check for coil bind in the springs due to the increased lift.

That ^

 

[Broncobowsher]

1.6 is stock
Going up to 1.7 means the valve spring pressure on the cam lob is now 1.7 times instead of 1.6. Since you have a little more lift, there is a little more pressure. If you try this you really need to watch the break in oil so you don't wipe a cam lobe.

 

[rguest3]

I recommend the Comp Cams Magnum Rockers - 1.6 Ratio and Roller Tip. Part number CCA-1442-16.

These are strong, fit under the stock Valve Cover, and may add a little HP.

 

[baddad457]

I recommend the Comp Cams Magnum Rockers - 1.6 Ratio and Roller Tip. Part number CCA-1442-16.

These are strong, fit under the stock Valve Cover, and may add a little HP.

Those are a waste of money. Better to spend a few dollars extra and get full rollers and get the true benefit of the roller trunions. The roller tip does virtually nothing to eliminate friction. If you'll watch a std rocker in motion at the valve, the tip actually rolls across the tip in service, the tip is curved slightly to facilitate this.

 

[rastiss]

1.6 is stock. and as mentioned, you don't gain anything worth noting if you don't go full roller. even then, you won't feel any realistic difference....going to 1.7's will make some difference. you'll need to check for coil bind and piston clearance to be safe. ive got a 306 with eddy heads and 1.72 rockers. it ran low to mid 7's in the 1/8th in a factory five cobra replica.