Roller Rockers...

[Fast63]

you're absolutely right Foxfan

 

[stykthyn]

wont he need to have his stock heads machined to accept a stud mount? for a daily I would stick with the 1.6 pedestal mount

 

[NKau]

wont he need to have his stock heads machined to accept a stud mount? for a daily I would stick with the 1.6 pedestal mount

It's a good thing you mentioned this. Sounded like the OP wanted to put them on his stock heads, then transfer them to better heads down the road. Not really feasible unless you have your heads machined for studs or buy aftermarket heads with crappy pedestal mount rockers; neither of which make a lot of sense.

 

[88mouse]

so i'm going to be putting them on my stock heads and then switching them over to my GT40's whenever I get those. Does anyone see any problems with a 1.6 ratio RR, with a 3/8 stud mount? Thanks.

Are the gt40x's are stud mounted?

If they are the stud mounted rockers won't work on stock heads.

 

[Foxfan88]

FWIW crane makes a stud rocker conversion for stock heads. its a 3/8 stud for the rockers that has 5/16 threads on bottom that will screw into the 5/16 hole where the pedestal rockers bolted down originally. it also comes with guide plates and is rather affordable.. under 100 bucks last time i checked. the only bad thing is your using a 5/16 bolt in the head. not very strong and poses a greater chance of breaking with stiffer valve springs etc etc. but i guess it couldnt be much weaker than the stock setup because it used the 5/16 bolt also.

a better alternative is to have the holes in the head drilled out and tapped into a 3/8 thread so you can run a conventional stud.

 

[Foxfan88]

Are the gt40x's are stud mounted?

If they are the stud mounted rockers won't work on stock heads.

IIRC gt40x are pedestal mount

 

[5spd GT]

Simply take Excel to look at the differences in rocker ratios and how the lift changes exponentially.

Trickflow Stage 1

Lobe Lift - 1.6 RR - 1.7 RR - 1.8 RR

0.010 - 0.016- 0.017 - 0.018
0.020 - 0.032- 0.034 - 0.036
0.030 - 0.048- 0.051 - 0.054
0.040 - 0.064- 0.068 - 0.072
0.050 - 0.080- 0.085 - 0.090
0.060 - 0.096- 0.102 - 0.108
0.070 - 0.112- 0.119 - 0.126
0.080 - 0.128- 0.136 - 0.144
0.090 - 0.144- 0.153 - 0.162
0.100 - 0.160- 0.170 - 0.180
0.120 - 0.192- 0.204 - 0.216
0.130 - 0.208- 0.221 - 0.234
0.140 - 0.224- 0.238 - 0.252
0.150 - 0.240- 0.255 - 0.270
0.160 - 0.256- 0.272 - 0.288
0.170 - 0.272- 0.289 - 0.306
0.180 - 0.288- 0.306 - 0.324
0.190 - 0.304- 0.323 - 0.342
0.200 - 0.320- 0.340 - 0.360
0.210 - 0.336- 0.357 - 0.378
0.220 - 0.352- 0.374 - 0.396
0.230 - 0.368- 0.391 - 0.414
0.240 - 0.384- 0.408 - 0.432
0.250 - 0.400- 0.425 - 0.450
0.260 - 0.416- 0.442 - 0.468
0.270 - 0.432- 0.459 - 0.486
0.280 - 0.448- 0.476 - 0.504
0.290 - 0.464- 0.493 - 0.522
0.300 - 0.480- 0.510 - 0.540
0.310 - 0.496- 0.527 - 0.558
0.312 - 0.499- 0.530 - 0.562