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I would trust the Comp aluminum over Chinese $150 stainless knockoffs. Used them on quite a few builds .500 lift area and never had a failure. I have 3/8 studs with a stud girdle on my 383. I have also seen them Chinese knock off stainless rockers scatter needle bearings through the motor. I'm out.
I believe that it is, but how exactly do you tell?
# of degrees divided by lift or something weird like that?
The other thing that's making me think I should go with 1.5 ratio roller rockers is that the CFM of my heads doesn't really increase with more lift.
They flow 273 CFM @ 0.500" and 274 @ 0.600". With 1.5:1 RRs the valve lift is 0.562" and with 1.6:1 RR 0.600". My thought was that if the valve is opening more but not flowing more that also decreases air velocity (assuming that at that lift the valve curtain area is actually the bottle neck).
The one thing that's making me lean towards 1.6:1 ratio is the slight increase in duration; my Mike Jones cam's duration is rated with the assumption of a .750 diameter roller wheel or .800 diameter wheel; but my lifters are only 0.700; Mike said that I'd only lose about 1 degree of duration by going with the smaller diameter wheel so part of me just wants to get a tiny bit of duration back by going with the higher ratio RRs.
See diagram for how higher ratio RRs increase duration:
I honestly don't mind the added wear on the springs from 1.6 ratio RRs because I'd just use them wearing out as an excuse to get some lighter weight beehive springs.
Adam
Last edited by NewbVetteGuy; Dec 8, 2016 at 07:15 PM.
I believe that it is, but how exactly do you tell?
# of degrees divided by lift or something weird like that?
The other thing that's making me think I should go with 1.5 ratio roller rockers is that the CFM of my heads doesn't really increase with more lift.
They flow 273 CFM @ 0.500" and 274 @ 0.600". With 1.5:1 RRs the valve lift is 0.562" and with 1.6:1 RR 0.600". My thought was that if the valve is opening more but not flowing more that also decreases air velocity (assuming that at that lift the valve curtain area is actually the bottle neck).
The one thing that's making me lean towards 1.6:1 ratio is the slight increase in duration; my Mike Jones cam's duration is rated with the assumption of a .750 diameter roller wheel or .800 diameter wheel; but my lifters are only 0.700; Mike said that I'd only lose about 1 degree of duration by going with the smaller diameter wheel so part of me just wants to get a tiny bit of duration back by going with the higher ratio RRs.
See diagram for how higher ratio RRs increase duration:
I honestly don't mind the added wear on the springs from 1.6 ratio RRs because I'd just use them wearing out as an excuse to get some lighter weight beehive springs.
Adam
Sorry, don't get the comps I recommended. I did not realize the lift numbers you were going to have. Comp Pro Magnums are what I am running. Crower Enduro would be the other option. Neither is cheap but your talking a fast ramp cam with a lot of lift.
Just to report back; I'm just going to take out a 2nd mortgage and get the Comp Ultra Pro Magnum 7/16" 1.6 Ratio Roller Rockers.
As far as ARP studs.... Good god they make it hard!
For some reason my heads came with 3/8"-24 thread tops with 7/16"-14 thread bottoms; why they would "downgrade" the head from 7/16" to 3/8" is beyond me...
Now I'm trying to find the ARP version of that stud... It's not easy at all.
The jegs part says 7/16" -20 top, 7/16" 14 bottom with 11/16" hex in the middle.
It says 2.650" O.A.L. (no idea what that means)
1.68" stud height
1" thread top
.734" thread bottom
The closest I can find from ARP is ARP 134-7103, which says it's typically for small blocks.
They rate things in "B","C","D","E", & "F" dimensions.
E: 7/16"-20
F: 7/16"-14
-Cool I can tell what that is so far, so good.
B: 1.770" -wtf is this?
C: .700" wtf is this?
D: .670" wtf is this?
I can't find an AFR part with #'s that match the Jegs part. The jegs part is $28; ARP $50+; is this a place where the extra $ is worth it?
As far as the guideplates... They're VERY simple, flat guideplates that specifically say I may need to machine them as appropriate.
They're 5/16" and it says I should use 5/16" hardened pushrods with them.
Not sure if they're hardened or not, but obviously I don't want little chunks of metal being ground off through friction and falling down into the engine; I'm assuming Jegs wouldn't sell me something wholly inappropriate.... http://www.jegs.com/i/JEGS-Performan...02000/10002/-1
Adam
Last edited by NewbVetteGuy; Dec 9, 2016 at 06:52 PM.
ARP has high tensile strength studs. 7/16 rockers fit on 7/16th studs not interchangeable with the 3/8th counter parts
I install rocker studs with sealant because there are certain thing that i don't like to use loc-tite blue or red on. because it takes heat to dissassemble.
In late November I bought the Jegs 195cc Profiler heads. Then on the basis of the recommendations here I swapped the rocker studs out for 7/16" and used the Permatex sealant on them. -Just finished that today.
-Now how much do I torque these suckers? -Just use my new torque wrench and a super deep well socket-right?
So far, I'm really enjoying the interior and engine work; @$#@$ parking brake, not so much.
I bought a polishing kit and I'm getting an old set of 1.6" and 2.02" valve to temporarily put into each combustion chamber and I'm going to do some minor touch-up / light polishing on the chambers for sure. Realize I'll probably have to buy a kit to measure chamber volume but if I'm only going to do this once, I want do it right.
Considering sending heads away to get the chambers, exhaust valves, and exhaust ports coated, too; depending upon cost. -Because I'm OCD and I like the idea of a 5% improvement in fuel economy -I realize that's only 1 mpg, but it's my car and I can be as OCD as I wanna be! ;-)
The value for the HP and torque kings...
An assembled head that can get you over 400hp & 400ft lbs in a 350 and 500hp with a good cam in a 383 for under $1000 including tax and shipping- YES PLEASE!
The reason why you lift the valves higher even if the heads don't flow any more CFM is because the valves then spend more (Time) at max CFM.
At higher rpm your valves are spending very little time being open and closed. Duration changes the amount of time. Lift and ramp speed is the amount of total flow during that time.
That is why a roller motor can make so much more power over a flat tappet cam.
In late November I bought the Jegs 195cc Profiler heads. Then on the basis of the recommendations here I swapped the rocker studs out for 7/16" and used the Permatex sealant on them. -Just finished that today.
-Now how much do I torque these suckers? -Just use my new torque wrench and a super deep well socket-right?
Well THAT'S embarrassing but reassuring- for some reason I was looking for the spec on the rocker stud page and not the heads' page.
Jegs support emailed me back 50lbs-and I got lucky there because that's exactly what I torqued them too. I might have to reposition them after installing pushrods- or even drill them out as I went with 1.6 ratio RRs so probably not a big deal right now.
