i have 1.6 and 1.7 RR's, which ones should i run with my setup?

[cenok is family]

i'm about to put my motor back together, but can't decide which set i'm going to install. i have some crane/ford 1.7 roller rockers and a set of proform 1.6 rockers. my mods are everything in my sig, and i'm installing a set of thumper heads with 1.94/1.6 valves, an afm n-412 cam, and my 24# squirter's are going back on with a matching 75mm proflow MAF. afm's site says to use 1.6's, but what do you guys think? here are the specs on my cam:

N-412 Cam Spec

Engine 302HO/351

Duration at .006 -- Int. 276 Exh. 284
Duration at .050 -- Int. 222 Exh. 230
Timing events at .050 --Int. 3/39 Exh. 51/-1
Lobe lift @ cam -- Int. .320 Exh. .320

Gross Valve Lift w/1.6 Int. 0.512 Exh. 0.512

-Lobe Seperation 112
-Degree intake Lobe to 108
-Valve Lash (hot) Int. & Exh. 0

the lift will be .544 with the 1.7's. and ptv clearance won't be an issue with my pistons.

 

[92notch6886]

Ive heard bad stuff about Proform parts, so i will say the Crane/Ford rockers

 

[PUNISHER RACING]

id go with the 1.6

 

[NIKwoaC]

All else equal, the 1.7s by definition are going to give you more flow, and thus, more power. As for quality of parts, I can't say.

 

[lang williams]

have you considered running the 1.6's on the intake side an 1.7's on exhaust since the exhaust side of the heads don't flow quite as well.

 

[stykthyn]

have you considered running the 1.6's on the intake side an 1.7's on exhaust since the exhaust side of the heads don't flow quite as well.

you can do that? where you would you find a set of 8 rocker arms?

 

[joel5.0]

Check their (split ratios) items.... sets of (8) 1.6 and (8) 1.7 ratio rockers...... stud mount only though.

 

[lang williams]

you have to have 2 sets to do it, but then you have 2 sets of split ratio! My friend does it on his 3 cam 100 shot car.

 

[cenok is family]

have you considered running the 1.6's on the intake side an 1.7's on exhaust since the exhaust side of the heads don't flow quite as well.

yeah i actually have heard about doing that and it did cross my mind, but i havent really heard that much about it and any effects, if any. but if i were to do that, why shouldn't i just run straight 1.7's?

 

[NIKwoaC]

yeah i actually have heard about doing that and it did cross my mind, but i havent really heard that much about it and any effects, if any. but if i were to do that, why shouldn't i just run straight 1.7's?

I would think that you should just run the 1.7s, especially since you feel like P-T-V clearance won't be an issue. Build the motor with the 1.7s, run it a few times to make sure they work well, then sell the 1.6s to some sucker that wants to run split ratio. Either way, I think you may be splitting hairs, I've never heard of anyone making more than ~10hp by switching from stockers to rollers. I'd think switching between 1.6 and 1.7 RRs, you'll see even less difference.

 

[cenok is family]

I would think that you should just run the 1.7s, especially since you feel like P-T-V clearance won't be an issue. Build the motor with the 1.7s, run it a few times to make sure they work well, then sell the 1.6s to some sucker that wants to run split ratio. Either way, I think you may be splitting hairs, I've never heard of anyone making more than ~10hp by switching from stockers to rollers. I'd think switching between 1.6 and 1.7 RRs, you'll see even less difference.

yeah that's probably what i'm going to end up doing. hah yeah i didn't think this was going to be the 'end all' power maker, but since i have both, i wanted to make sure i have the better set in there. thanks everyone for your input!

 

[5spd GT]

I would use the one that the camshaft lobe is designed for.

No need to run splits.

Good Luck!