The Chevrolet Rocker thread.

The Big Block of inline Ford sixes

Moderator: Mod Squad

The Chevrolet Rocker thread.

Postby SuperMag » Fri Jan 11, 2008 9:56 pm

FAQ material:

Q: I've heard alot about using chevy inline six rocker arms for a cheap performance gain, what is this? How hard is it to do?

A: To do this with no additional parts, you need pedestal mount rockers and 3/8" studs (which engines can these be found in? '85 for the pedestal mount rockers, what 'bout the studs?) (what is needed to do this for an EFI head is below) Basically, using rockers from any 192/250/292 cubic inch chevy inline six (go to the store and ask for rockers for a '75 Chevy C-10 with a 250 I6),

broncr wrote:IF you have pedastal mount rockers AND 3/8" studs, this is a good, CHEAP shortcut. Unless you have a very high lift cam (in which case you MIGHT encounter problems), you can increase your rocker ratio from 1.6 to 1.7, for about $30 -$40. REMEMBER, Mr1ford said he did this swap with a .487/.462 lift cam - in his opening post.

ALL it involves is replacing the stock, pedastal style rocker with the chebby one, and using a lock nut to properly adjust the valve clearance. I ended up double-nutting ALL of the studs, as one lock nut had lost it's bite.

I think most any cam would provide more lift/duration, but it would take another $70 to $100+(for the cam) AND significantly more time. I did the rocker swap & readjusted the valve train in a bit over an hour.

IIRC, the lift for the stock cam is .400. By switching to the chebby 1.7, it should now be .425. Not a BIG deal but, as mentioned earlier, cheap, quick and effective. :D

Thanks again, Mr1ford :!:


80broncoman wrote:A pedestal mount 300 head can use stud mount rockers if you use a pushrod guidplate conversion kit. I have intsalled it on my 90 cyl head and it all works just fine. Crane part number 36655-16 will give you 3/8 studs and guideplate for 5/16 pushrods. If you go this route hardened pushrods are not required becuse the kit has nylon inserts in the guidplates. I had to mix a couple of kits on mine cause I needed 7/16 studs for BBC rockers I already had. It is best for long life of the nylon inserts if you polish the pushrods to make sure there are no burrs on them. This is easy to do in a drill.
This conversion kit will also make your valvtrain adjustable.

broncr wrote:
broncr wrote:...the link to the post on the Isky guideplates for our 300's?...


It took a while...(& courtesy of Tetraruby300 - :) )

www.iskycams.com/category_template.php? ... ory_id=167

Note the fine print on the larger pic's -" picture may not exactly match actual product" - they all show a SET of adjustable guideplates.

originating thread can be found here

more relevant info can be found over here
brocr wrote:Q: what screw in stud sizes should I consider, and why?

SuperMag wrote:Specifically, Big Block Chevrolet 7/16" studs. The shaft is 7/16", but the part that screws into the head is 3/8", thus enabling you to use the existing 3/8" hole. Helps in keeping the price down...


Q: Which heads have provisions that allow a direct bolt on of Chebby rockers?
A:
82F100SWB wrote:This I think might be 84 and older with stud mount rockers, if there is any that allows it to be a direct bolt on, I seem to recall that there isn't.

Q: which rockers can i use for my BB6?
A:
StrangeRanger wrote:SBF rockers will not fit a 300.
GMC I6 rockers will fit
BBC rockers can be made to fit
385 series rockers (429/460) can allegedly be made to fit, there has been some dispute.

Q: what was the year of the head change over to pedastal mount rockers
A: 1985 was the first year for pedistal mount rockers
Courtesy of a PM by Other Evan
"...and he that hath no sword, let him sell his cloak and buy one." --Luke 22:36
User avatar
SuperMag
VIP Member
 
Posts: 3367
Joined: Sat Nov 16, 2002 12:29 am
Location: God's Country, Idaho

Postby 66 E100 Pickup » Sun Jan 13, 2008 2:02 am

Hi SuperMag,

Can you link this thread back over to the roller rocker thread--I've posted more info and photos regarding the I6 chevy rocker and the BBC roller rocker (on the early 240 head).

Thanks,

John
66 E100 Pickup
Registered User
 
Posts: 847
Joined: Sat Mar 24, 2007 5:38 pm
Location: Fresno, CA.

Postby Lazy JW » Sun Jan 13, 2008 12:04 pm

Here is a link to some stamped-steel Chebbie rockers by Manley that are 1.6 ratio. No real advantage other than they are lighter weight than the stock cast Ford units. If someone were doing a rebuild and planned to replace worn-out rockers but wanted to retain the stock ratio they may be worth a look-see.
Joe

EDIT: I deleted the link because I realized that those are for the SBC V8 and may be different from the Chebbie Six rockers. Joe
74 F-350 300-6, EFI manifolds into single exhaust, Carter YF, T-18B, Dana70 w/4.11, Flatbed dually w/dump bed. Great farm truck!
Image
Lazy JW
FSP Moderator
 
Posts: 6272
Joined: Fri May 16, 2003 10:25 pm
Location: Careywood, Idaho

Postby SuperMag » Sun Jan 13, 2008 3:10 pm

66 E100 Pickup wrote:Hi SuperMag,

Can you link this thread back over to the roller rocker thread--I've posted more info and photos regarding the I6 chevy rocker and the BBC roller rocker (on the early 240 head).

Thanks,

John


Done. :wink:
User avatar
SuperMag
VIP Member
 
Posts: 3367
Joined: Sat Nov 16, 2002 12:29 am
Location: God's Country, Idaho

Postby Modifyre » Wed Aug 13, 2008 4:15 pm

Hi guys. I had an interesting conversation with a Comp Cams help guy today and just wanted to see what you thought. Didn't realize a simple cam swap would be such a pain but the machinist where I brought my head told me I needed the springs that were recommended by the cam sheet. Didn't even look at them but luckily the performance shop nearby got them in the next day... I have Comp Cams # 66-237-4 which is the 260H cam and the springs I bought are the #903-12 springs. After talking to the machinist he told me that with the factory valve spring retainers he only had around 1.68" of height even with the +50 locks. I immediately asked about machining the spring seats and he said that he didn't like to "compromise" the head like that because the seats are too close to the water jacket. The springs call for 1.7" so I thought it would be best to call Comp. After holding for quite a while, I told the guy on the other end the parts I had and the problem I had. After calculating with the stock ratio @ .447 lift he hummed and hawed and said that technically I could go as low as 1.64" but he said, "I wouldn't". He said 1.68" should be fine. When I mentioned about going to a 1.7 ratio rocker he immediately stopped me in my tracks saying that now the lift would be up around .470 something and that's not good. Unfortunately I already bought the 3/8" rocker stud conversion AND the 1.7 ratio Chevy rockers. I guess I just wasted a bunch of money except for having adjustable rockers, and I now gotta get stock pre '85 rockers because the Chevy's will just sit here... ??

Any opinions? comments?

Darren
'85 F-150 2WD LWB I-6 carb w/ no emissions junk, 5-speed manual (M5OD), EFI exhaust manifolds w/ shortened exhaust and high flow muffler.
Future mods: TBI EFI conversion w/ Offy intake, GM TBI unit and Megasquirt computer, COMP 260H cam, ported/polished head, upgraded fuel pump and injectors, full dual exhaust.
"Far Away" mods *CHANGED*: Turbocharging.
Modifyre
Registered User
 
Posts: 33
Joined: Mon Jun 16, 2003 5:35 pm
Location: Hamilton, Ontario, Canada

Postby Harte3 » Wed Aug 13, 2008 4:51 pm

The Chebby rocker swap is usually the $40 upgrade on a bone stock cam and usually not recommended on an upgraded cam. I had a set of new stock rockers and a set of new Chebby rockers when I had my engine built. The builder suggested stay with the stock rockers...so that's what I did.
'83 F150 300, 0.030 over, Offy DP, Holley 4160/1848-1 465 cfm, Comp Cam 260H. P/P head, EFI exhaust manifolds, Walker Y Pipe, Super Cat, Turbo muffler, Recurved DSII, Mallory HyFire 6a, ACCEL Super Stock Coil, Taylor 8mm Wires, EFI plugs.
User avatar
Harte3
VIP Member
 
Posts: 2442
Joined: Sat Oct 21, 2006 9:17 pm
Location: Spokane, WA

Re: The Chevrolet Rocker thread.

Postby MX500 » Thu Aug 14, 2008 5:31 pm

SuperMag wrote:FAQ material:

StrangeRanger wrote:SBF rockers will not fit a 300.
GMC I6 rockers will fit
BBC rockers can be made to fit
385 series rockers (429/460) can allegedly be made to fit, there has been some dispute.

Q: what was the year of the head change over to pedastal mount rockers
A: 1985 was the first year for pedistal mount rockers
Courtesy of a PM by Other Evan



385 series engines include (IIRC) the 351M/400. I know their rockers are interchangeable with the 460 rockers.
MX500
Registered User
 
Posts: 32
Joined: Sat Jul 26, 2008 1:12 pm

Postby 80broncoman » Fri Aug 15, 2008 3:05 pm

Modifyre wrote:Hi guys. I had an interesting conversation with a Comp Cams help guy today and just wanted to see what you thought. Didn't realize a simple cam swap would be such a pain but the machinist where I brought my head told me I needed the springs that were recommended by the cam sheet. Didn't even look at them but luckily the performance shop nearby got them in the next day... I have Comp Cams # 66-237-4 which is the 260H cam and the springs I bought are the #903-12 springs. After talking to the machinist he told me that with the factory valve spring retainers he only had around 1.68" of height even with the +50 locks. I immediately asked about machining the spring seats and he said that he didn't like to "compromise" the head like that because the seats are too close to the water jacket. The springs call for 1.7" so I thought it would be best to call Comp. After holding for quite a while, I told the guy on the other end the parts I had and the problem I had. After calculating with the stock ratio @ .447 lift he hummed and hawed and said that technically I could go as low as 1.64" but he said, "I wouldn't". He said 1.68" should be fine. When I mentioned about going to a 1.7 ratio rocker he immediately stopped me in my tracks saying that now the lift would be up around .470 something and that's not good. Unfortunately I already bought the 3/8" rocker stud conversion AND the 1.7 ratio Chevy rockers. I guess I just wasted a bunch of money except for having adjustable rockers, and I now gotta get stock pre '85 rockers because the Chevy's will just sit here... ??

Any opinions? comments?

Darren


Surely Comp has a spring that can work with that cam and .470 lift.
Just going to 1.65 instaead of the 1.7 recommend for thier spring is going to greatly increase the seat pressure.
If they really have nothing I know crane has more than a few spring that will work although some springs will require different retainers.
OAPSE Union Member

Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh
User avatar
80broncoman
Global Moderator
 
Posts: 5486
Joined: Sat Oct 18, 2003 10:49 pm
Location: The Great state of Ohio!!

Postby Modifyre » Fri Aug 15, 2008 5:40 pm

As it turns out my machinist took some hardened steel Comp retainers and turned them down the amount he needed to get the 1.7" spring height. Now I'm curious if I could use those Che-y rockers but I think I'll just stick to stock right now and see how the new cam is.

Darren
'85 F-150 2WD LWB I-6 carb w/ no emissions junk, 5-speed manual (M5OD), EFI exhaust manifolds w/ shortened exhaust and high flow muffler.
Future mods: TBI EFI conversion w/ Offy intake, GM TBI unit and Megasquirt computer, COMP 260H cam, ported/polished head, upgraded fuel pump and injectors, full dual exhaust.
"Far Away" mods *CHANGED*: Turbocharging.
Modifyre
Registered User
 
Posts: 33
Joined: Mon Jun 16, 2003 5:35 pm
Location: Hamilton, Ontario, Canada

Postby Craigwell » Fri Oct 03, 2008 9:44 pm

Ok .. has anyone accomplished a Rocker Arm swap with stud mount rockers??
1995 F150 4x4 4.9L E4OD Mule / Plow Truck
Gone but not forgotten: 1976 F250 4x4 300 six, NP435. Dana60/44HD 4.10 Traction Lok, EFI Exhaust, 240 Head
User avatar
Craigwell
Registered User
 
Posts: 704
Joined: Thu Sep 16, 2004 12:37 pm
Location: Atlantica, Canada

Postby rhetor » Sat Oct 04, 2008 2:26 pm

I used Scorpion 1.73:1 aluminum roller rockers for 351C/460 motor.

I had to remove .110" from the pedastals of the rockers and also some material from the u-channel factory pieces.

These was for a 1995 EFI head with BOLT DOWN rockers.
300- mild head porting - 204/214 cam - 1.73 rollers - 2.5" exhaust DEAD AND GONE!

New truck- 71 F-100 302/AOD. Missing my 300 dearly. 302 belongs in a mustang, lifters tick, headers sound annoying, vibrates, is ugly, etc.
User avatar
rhetor
Registered User
 
Posts: 797
Joined: Mon Aug 04, 2003 9:05 pm

Postby Lazy JW » Sat Oct 04, 2008 3:00 pm

Craigwell wrote:Ok .. has anyone accomplished a Rocker Arm swap with stud mount rockers??


Yup. They bolted right onto my 78 300 head.
74 F-350 300-6, EFI manifolds into single exhaust, Carter YF, T-18B, Dana70 w/4.11, Flatbed dually w/dump bed. Great farm truck!
Image
Lazy JW
FSP Moderator
 
Posts: 6272
Joined: Fri May 16, 2003 10:25 pm
Location: Careywood, Idaho

Postby Craigwell » Sat Oct 04, 2008 9:44 pm

Ok Thanks. After a closer look, I did see the appropriate link above in the initial post.

I'll be giving this a shot with my 1981 Stud mount head. I just need to check if they are 3/8 studs or 5/16.

Thanks to everyone for great information.
1995 F150 4x4 4.9L E4OD Mule / Plow Truck
Gone but not forgotten: 1976 F250 4x4 300 six, NP435. Dana60/44HD 4.10 Traction Lok, EFI Exhaust, 240 Head
User avatar
Craigwell
Registered User
 
Posts: 704
Joined: Thu Sep 16, 2004 12:37 pm
Location: Atlantica, Canada

Postby thunderb » Tue Oct 07, 2008 1:42 pm

Craigwell wrote:Ok .. has anyone accomplished a Rocker Arm swap with stud mount rockers??


Me too. Worked fine for me. I just torqued them down to spec for the '79. I used the stock lock nuts with the new rockers and pivots.
'79 F100 SB
Hurst Mastershift 3speed floor shift conversion
Offy (divided single plane)
Holley 390
EFI manifolds
Chebbie Rockers
Summit Racing 3.50 gearset

My Truck:
http://www.ford-trucks.com/user_gallery ... umid=21535
User avatar
thunderb
Registered User
 
Posts: 207
Joined: Thu Jun 23, 2005 8:55 am

Re: The Chevrolet Rocker thread.

Postby F-250 Restorer » Wed Apr 21, 2010 2:49 am

I just wanted to add that Crane Cams makes BBC rockers for 3/8" studs. They are for a 409, pn 15750-16.
F-250 Restorer
Registered User
 
Posts: 327
Joined: Wed Jan 13, 2010 11:42 pm

Re: The Chevrolet Rocker thread.

Postby julianc » Mon Apr 15, 2013 12:41 pm

I will go for the stock ratio Harland Sharp ones. I don t know which screw in arp rocker studs to buy, can someone help me ?? http://arp-bolts.com/pages/viewcatalog.shtml page 54 I have all the options. I have pushed in studs but will be tapping the thread holes for some screw in rocker studs.
julianc
Registered User
 
Posts: 8
Joined: Wed Dec 19, 2012 6:28 pm

Re: The Chevrolet Rocker thread.

Postby 80broncoman » Sat May 04, 2013 11:54 pm

julianc wrote:I will go for the stock ratio Harland Sharp ones. I don t know which screw in arp rocker studs to buy, can someone help me ?? http://arp-bolts.com/pages/viewcatalog.shtml page 54 I have all the options. I have pushed in studs but will be tapping the thread holes for some screw in rocker studs.


Here is the way I would do it.
1st Don't pull out alll of stock studs tilll you take some measurements.
2nd I'd measure down the length of the stock stud to the casting.
then look at the height of the hex on new studs. That is the amount that you would mill off the head stud bosses.
Also remember if you head has round holes for the pushrods and not milled slots you will guideplates and heattreated pushrods.
OAPSE Union Member

Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh
User avatar
80broncoman
Global Moderator
 
Posts: 5486
Joined: Sat Oct 18, 2003 10:49 pm
Location: The Great state of Ohio!!


Return to 240-300 "Big Block" Six Performance

Who is online

Users browsing this forum: Bing [Bot] and 0 guests

cron