Hey guys, I am doing my top end this winter, adding afr 165's, trick flow street heat intake, 65m TB and 1.7 rockers, should I get heads for pedistol mount rockers or stud mount, leaving the stock cam.
well, from what I have read, with a supercharged application like mine, you can get away with the stock cam without loosing lots of hp and keep your idle quality, its a daily driver. Why go with the stud mount?
I would also like to know the pros/cons of stud vs. pedestal, as I am looking at replacing my GT40 Iron heads with an aluminum head this winter. Due to $$, I would like to stay with the pedestal rocker arms with the new heads. What is everyone's opinions?
Given a choice, always go with stud mounts. Unless, of coruse you're going shaft rockers. Reasons: 1) MUCH easier to adjust, no shims. 2) Stronger, 5/16 bolts VS. 7/16 stud. Don't even think about the 5/16 to 3/8 coversion pieces, they're still 5/16 on the bottom. If you are ordering the heads and they are available either way, go for the stud type. If you already have fulcrum style heads, they can be changed by a GOOD machine shop $$. DO NOT try this at home unless you have a vertical mill (Bridgeport) because it MUST be done properly or you'll have junk. BTW, the strong valve springs, required for a "big" cam , can easily pull 5/16 bolts out of the heads.
Given a choice, always go with stud mounts. Unless, of coruse you're going shaft rockers. Reasons: 1) MUCH easier to adjust, no shims. 2) Stronger, 5/16 bolts VS. 7/16 stud. Don't even think about the 5/16 to 3/8 coversion pieces, they're still 5/16 on the bottom. If you are ordering the heads and they are available either way, go for the stud type. If you already have fulcrum style heads, they can be changed by a GOOD machine shop $$. DO NOT try this at home unless you have a vertical mill (Bridgeport) because it MUST be done properly or you'll have junk. BTW, the strong valve springs, required for a "big" cam , can easily pull 5/16 bolts out of the heads.
3/8" rocker studs will be fine as well, lots of rockers avail for that application. All the Edelbrock stud mount heads use 3/8" studs and all small block Chevy's use 3/8" studs. The only motors I knew of that use 7/16" rocker studs are big blocks.
My vote is for pedestal mount. Only reason why is that I have had bad experience with stud mount. The pedestal mount 1.7's always stayed tight on my friends car. Could not have been happier. He moved over to trick flow heads with stud mount rockers, and we have had nothing but problems with it. They always come loose no matter what we do. We asked tons of questions about how to properly set them, but nothing worked.
Stud mount rockers should NEVER loosen up.
All Ford rockers I have seen use good locking nuts, those hold on nice and tight Not the cheapo Knurled or Nylock nuts that cheapo Chevys use that only hold tight the first time put on the stud.
The studs are screwed into the heads, cheapo Chevy heads have pressed in studs, those can pull out over time.
As long as you adjust the valves properly you will have no problems. Use the Intake Close / Exhaust open method. When the intake valve Just closes, adjust the Exhaust valve on that cyllinder, when the Exhaust valve JUST starts to open, adjust the Intake valve.
With Hydraulic lifters, go with 1/4 turn past zero lash. VERY IMPORTANT do not use the spinning the pushrod method to find zero lash.
The trick is to snug down the nut till the point the rocker JUST will not rock back and forth, this is the real Zero lash. This is the point where all the slack between the pushrod, valve and lifter is taken up without starting to depress the plunger on the lifter.
The spinning pushrod method fails beacuse some of the lifters will be "pumped up" or full of oil and will feel solid and not depress easily. So when you find zero lash the pushrod will not be easlily spun. But some lifters will bleed down and the plunger will easily depress at zero lash, and you will end up pushing the plunger nearly all the way down before the pushrod stops spinning.
Having adjustable stud mount rockers is the way to go, trash the net lash pedastal mounts I can't imagine how much of a pain it is to find the proper preload with shims etc, plus the weak 5/16 bolts with 1.7 rockers icko.
Stud mount rockers are more forgiving of pushrod length issues too, but it still does pay to have the right length in the long run with any setup
I would forgive someone with a nice set of 1.7 pedastal rollers that did not want to buy a new set, but heck, you can sell em on EBAY