1.6 Roller rockers
 

A buddy of mine wants to sell his for $100.00, it it worth it on a stock motor, and is there a big difference between the 1.6 and 1.7?

thanks,
Leo



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1990GT 5.0 302, T-5, 3.73's, K&n Air filter, Dynomax Super Turbo Exhaust, Hypertech Chip, MSD 6A Ignition, RAM Clutch, Motorsport 3 core, Offroad H-pipe.

Well that depends. the biggest benfit from a set of roller rockers are more accurate ratio's vs. the stock rockers. the added benefits are reduced friction and side loads on the valve. As far as the 1.7 vs. 1.6 thing that depends on how well the heads flow. as an example. I believe the stock HO cam has a lift of .444 (with a 1.6). So the lobe lift is 0.2775.

0.2775 x 1.6 = .444
0.2775 x 1.7 = .472
0.2775 x 1.73 = .480

Stock E7TE heads zonk out at .500 lift, so yeah they are worth some power simply due to the fact there is still some flow left in the heads and at the very least you pass the .444 flow mark twice as the valve opens and closes (rather than once with a 1.6 rocker). the flip side of higher rocker arm ratio's. they increase the amount of load on lifter and decrease the RPM potential of the motor. I wanna say that on a brand X motor going from a 1.5 to a 1.6 lowers peak rpm by 300 (as a rule of thumb)

So, what you are saying is that on a stock motor/cam, use the 1.7's, and the 1.6's if you plan on changing the cam, too?

Yeah on a bone stock H.O motor, a set of 1.7's won't out pace the cylinder heads. If you plan on installing a cam with more than .480 lift then get the 1.6's if your using stock heads. On the intake side more lift beyond .500 doesn't help do that much. Except maybe simulate a bit more duration