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pushrod guide plate issue

8K views 36 replies 5 participants last post by  oilbnr 
#1 ·
Ok, so I'm at the point of checking piston to valve clearance on my stroker motor. I'm using the ford motor sports Z304 heads with the offset intake valves, and the scorpion offset roller rockers for those heads. I bought what I though were the correct pushrod guide plates from Speedway motors, but putting everything together, the rocker roller tips are no where near where they should be. Should I cut the Speedway guides and weld a tab across them once in the correct place, or buy a set of adjustable plates from comp, or afr, etc.??
 
#2 ·
You can do it either way, but I would call speedway first and see if they have another option or suggestion. They could poss take them back also if you wanted to try and re coup a little cash to purchace the others you mentioned...
 
#4 ·
I have the correct set from Z304 heads .

will sell for $54 plus $8 USPS flat rate they are new
Dan could you tell me some dimensions of the ones you have, ie. the spacing between the pushrod slots, and the approximate offset of the intake slot from center of the intake rocker stud hole? I'm a little worried about spending more money on something that may not work. Here are the ones I bought from Speedway.....
Ford N351 Head Pushrod Guide Plates - Speedway Motors, America's Oldest Speed Shop
 
#10 ·
they are right out of the box of new Z heads . Z304 first came out , Ford gave the g/plates with them . can always do what I did , get Jesel shaft rockers
Thanks for your offer Dan, but I think I would end up with the same plates as I have now. Going the Jesel route is not an option, as I'm only running a hydraulic cam, 6400 rpms at best, and I'm retired on a fixed income, can't really afford the cost of Jesel stuff.
 
#12 ·
Thanks for your offer Dan, but I think I would end up with the same plates as I have now. Going the Jesel route is not an option, as I'm only running a hydraulic cam, 6400 rpms at best, and I'm retired on a fixed income, can't really afford the cost of Jesel stuff.
I know the difference between N and Z and straight on plates​
 
#11 ·
If it's easier, the alternative way to make solid check lifters is to pull the guts and flip the check valve. Some require grinding to get the perfect zero-height on reassembly. Be sure to mark them as TEST lifters. ;) Yeah, I still kick my self for not getting a couple extra pairs of Z304s when they were on sale from FRPP last year. Complete, assembled, with valves, springs, etc., the correct K351 roller rockers, and guide plates for $1200. Total. For the pair. Damn.
:(
David
 
#13 ·
If it's easier, the alternative way to make solid check lifters is to pull the guts and flip the check valve. Some require grinding to get the perfect zero-height on reassembly. Be sure to mark them as TEST lifters. ;) Yeah, I still kick my self for not getting a couple extra pairs of Z304s when they were on sale from FRPP last year. Complete, assembled, with valves, springs, etc., the correct K351 roller rockers, and guide plates for $1200. Total. For the pair. Damn.
:(
David
"kick my self" ......didnt know , wish I did , Iam kicking myself . I'll be back when done
 
#20 ·
Re: pushrod guide plate issue......continued

Ok, so I sent the duplicate set of plates back, and went back to assembling the valve train to check the piston to valve clearance. Attached are pictures of what I am ending up with. The guide plates are supposed to be for the Z304 head, and the Scorpion rockers are the set with offset intake for the Z304 head. I have cut one of the plates apart and located them where the roller tips of the rocker arms are centered on the valve tips. You can see how far the gap is between the two pieces. My plan is to get some steel plate and tack weld it across the halves to keep them in place, then remove them and finish welding them. That way I know everything will end up where it is supposed to. Anyone have any other ideas??
 

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#21 ·
I dunno, the one rocker (right side in pic) doesnt look correct to me. Have you tried swapping them or a different rocker? Seems if they are the correct "offset" rocker it wouldnt set sideways...... :confused::confused:

Maybe someone else will jump back in...
 
#22 ·
I dunno, the one rocker (right side in pic) doesnt look correct to me. Have you tried swapping them or a different rocker? Seems if they are the correct "offset" rocker it wouldnt set sideways...... :confused::confused:

Maybe someone else will jump back in...
Yep, tried all sorts of combinations and moving parts around. I'm scratching my head on this one. All the parts are supposed to be the correct ones for the heads. The only obvious thing was that the rocker arm stud holes are a tiny bit too far apart for the original guide plate, maybe less than 1/32 too far apart for the plate holes to clear the stud threads. Not any where near enough to effect the large offset issue. I know the key is to have the rocker arm rollers centered on the valve tips...
 
#23 · (Edited)
I'll bet you have a set of early Z304 heads that have the wider stud spacing and do not use the offset rockers. The later "D" head used narrower stud spacing and offset rockers. IIRC, the geometry was off a bit but do-able with the old heads, and shaft rockers were often used on high-end setups to solve angularity. Anyway, old heads had studs over 2" apart, and the newer heads were less than 2" apart. If yours are the older ones, try two non-offset rockers and an uncut plate for size.

David

PS: When I say "do-able", that's with corrective parts - not like yours is set. I would not run that. You can try some cycles with your setup, and you should see some heavy side-loading that won't last.
 
#24 ·
I'll bet you have a set of early Z304 heads that have the wider stud spacing and do not use the offset rockers. The later "D" head used narrower stud spacing and offset rockers. IIRC, the geometry was off a bit but do-able with the old heads, and shaft rockers were often used on high-end setups to solve angularity. Anyway, old heads had studs over 2" apart, and the newer heads were less than 2" apart. If yours are the older ones, try two non-offset rockers and an uncut plate for size.

David

PS: When I say "do-able", that's with corrective parts - not like yours is set. I would not run that. You can try some cycles with your setup, and you should see some heavy side-loading that won't last.
Just went out and measured a head....yep the stud holes are 2 1/16 apart on center. That is the information I needed. Thanks so much David. Will be going away for a couple days so will check with two straight rockers when I return. I was not aware that there were two different Z heads produced. I did try two straight rockers, but the roller tips were way off on the valves. Maybe with the different guide plates. Looks like I have the wrong set of rockers, and need a new set of guide plates. Crap. I'm retired and on a limited budget with this build, so this is going to hurt some. Thanks again.
Bob
 
#27 ·
Spoke with Ford Racing Performance tech today and, yes indeed, I have the earlier version of the Z304 heads. So the guide plates and off set roller rockers will not work on them. Great. He may have a set of the older style guide plates, will get back with me later. Not sure if I should just get 8 more Scorpion straight 6.5 rockers, or get a whole new set and try and sell the set for the Z304D heads.....more waiting now....:(
 
#28 ·
Spoke with Ford Racing Performance tech today and, yes indeed, I have the earlier version of the Z304 heads. So the guide plates and off set roller rockers will not work on them. Great. He may have a set of the older style guide plates, will get back with me later. Not sure if I should just get 8 more Scorpion straight 6.5 rockers, or get a whole new set and try and sell the set for the Z304D heads.....more waiting now....:(
I have the very first Z304's , they came with plates.

you never did answer if engine is a d/driver or race only . no need to now but I always have a reason for asking
 
#33 ·
Also, the ford tech said that I could also run an Eddy Vic Jr intake on the motor without any problems due to the motor size. I was planning on running the RPM performer that I ported.......he said the thing would have monsterous torque with that on it, but would loose a bit at top end compared to the vic jr. Again.... it's a street motor that will live between 2K and 4K mostly. Any thoughts......?
 
#34 ·
Also, the ford tech said that I could also run an Eddy Vic Jr intake on the motor without any problems due to the motor size. I was planning on running the RPM performer that I ported.......he said the thing would have monsterous torque with that on it, but would loose a bit at top end compared to the vic jr. Again.... it's a street motor that will live between 2K and 4K mostly. Any thoughts......?
for RPM mostly in the 2K _4K range and a street car , stay with the RPM Perf.

Plates , others read this forum .... plates are sold .

reason I ask about use of engine ... taking a page from the 227 SBC head , has the same type of intake rocker setup . ...plates for limited use and shafts for a driver
 
#36 ·
bait and hook, was an expression, nothing implied, and not actually a question even tho structure-wise it was a question

other than a way to get the OP'r to answer question

but did cryptically get the reason for asked question, dunno if OP did but I did
 
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