pushrod length question/adjusting valve train preload

84LX89GT · 01-03-2003, 03:35 AM

I just recieved my B303 cam and i'm going to be putting it on my 302 with my 1.7:1 Cobra roller rockers and GT40 heads.

I was wondering, will i have to change pushrod length or put shims underneath the pedestal mount rocker arms. I read in a ford manual that you use shims after milling the heads (or get shorter pushrods) and i've heard people put different length pushrods with different cams, but i'm not sure what i need to do in my case.

I'll have a total of .510" lift and i'm using new Ford hydraulic roller lifters.

I appreciate any input, thanks,

Rick

PKRWUD · 01-03-2003, 05:07 AM

You just need the standard 7.6" pushrods. The rockers should have come with shims, just in case you need them.

MEDIK418 · 01-03-2003, 12:29 PM

FYI. . . I installed an F303 last year with Ford Racing's roller rockers and didn't have to use any of the shims and havent' had any problems with it yet.

jonnyk · 01-03-2003, 12:35 PM

You may have to use shims based on the travel of the rocker arm across the valve stem. If the B303 has a smaller base circle than the stock cam, you may have to use a different length pushrod also. The best way to find out is to assemble it (correctly), and then turn the engine over by hand and watch the path of the rocker across the valve. You want as little movement as possible across the valve. It sounds tedious but if you do it right the first time, you won't have problems.

84LX89GT · 01-03-2003, 03:59 PM

awesome, thanks guys! I have no problem spending extra time making sure it's correct, i'd rather do it right the first time than to screw around and break stuff.

01-03-2003, 03:35 AM	#1
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	pushrod length question/adjusting valve train preload I just recieved my B303 cam and i'm going to be putting it on my 302 with my 1.7:1 Cobra roller rockers and GT40 heads. I was wondering, will i have to change pushrod length or put shims underneath the pedestal mount rocker arms. I read in a ford manual that you use shims after milling the heads (or get shorter pushrods) and i've heard people put different length pushrods with different cams, but i'm not sure what i need to do in my case. I'll have a total of .510" lift and i'm using new Ford hydraulic roller lifters. I appreciate any input, thanks, Rick __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

01-03-2003, 05:07 AM	#2
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	You just need the standard 7.6" pushrods. The rockers should have come with shims, just in case you need them. __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

01-03-2003, 12:29 PM	#3
MEDIK418 Registered Member Join Date: Mar 1999 Location: Amarillo, Texas, USA Posts: 780	FYI. . . I installed an F303 last year with Ford Racing's roller rockers and didn't have to use any of the shims and havent' had any problems with it yet. __________________ 1986 four-eyed LX coupe, 358 Cleveland, Tremec TKO600/centerforce clutch, dish cut Probe forged pistons, comp cams hyd.roller cam, .579/.588@224/230, Edel.performer, 670 holley street avenger, CPR custom built long tubes, ported and polished 4bbl heads, manley valves, beehive springs, MSD peo-billet dist/MSD6AL, fluidamper, 5 lug conv. with 17x8 bullits there's more but it's still not finished yet. Oh, and the oldest boy is turning his 89 GT into a FFR cobra this next summer.

01-03-2003, 12:35 PM	#4
jonnyk Being stroked is great Join Date: Oct 1998 Location: Alberta, Canada Posts: 772	You may have to use shims based on the travel of the rocker arm across the valve stem. If the B303 has a smaller base circle than the stock cam, you may have to use a different length pushrod also. The best way to find out is to assemble it (correctly), and then turn the engine over by hand and watch the path of the rocker across the valve. You want as little movement as possible across the valve. It sounds tedious but if you do it right the first time, you won't have problems. __________________ Novi 2000 now spinning off the snout of the 331... Mods Pics

01-03-2003, 03:59 PM	#5
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	awesome, thanks guys! I have no problem spending extra time making sure it's correct, i'd rather do it right the first time than to screw around and break stuff. __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

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