SBF GUIDEPLATE QUESTION

I'm assembling my best friends 347 and I'm running into troubles with the rocker arm geometry. The new AFR cnc'd heads have the valve locations moved so they came with AFR's adjustable guide plates. The trouble is they inter-lock together way too loose for my liking - as soon as you go to torque them they friggin move and mess up the adjustment and not only that it's damn near impossible to get the alignment right and not have the pushrod rubbing the head. Does anyone else make a better set of adjustable plates? My buddy said he had the same issue with his SBC AFR's and he had to use offset rocker arms to get the roller tips on the valve stems where they should be.

Tack weld

Already discussed that but that's not what I want to do nor does my buddy who owns the car...He wants it done right and I can't blame him there. I was looking at other brands on line and they appear to fit tighter so that might be the best option.

BigRigTech wrote:Already discussed that but that's not what I want to do nor does my buddy who owns the car...He wants it done right and I can't blame him there. I was looking at other brands on line and they appear to fit tighter so that might be the best option.

Hate to break your bubble, but "done right" most often involves custom work, welding, etc. beyond what comes in the box.  The world of building engines outside of factory issue involves custom fabrication.. don't expect to find everything fitting "online"

I realize this as I work on engines for a living but when you pay over $2000 for a set of heads you don't expect a $25 set of guide plates to fit as poorly as they do. I can deal with the guide plates but trying to get the tips completely on the valve stem is the real issue. If I get one side fit nice the other valve has the pushrod almost rubbing the head. After googling this issue it seems to be a common theme with these heads. My buddy said he corrected this problem with offset rocker arms on his last SBC build. I think he said in his case .050" offset did the trick but all I've seen online for SBF is .150" offset.

Weld um, hell i had to fab mine on my 563 outta some bbc stuff.

Aint no big deal its done all the time.

I'll run that up the flag pole with him again, he wont be home for 10 days, he's sitting somewhere off Newfoundland on a Coast Guard boat in the Atlantic....Yet he can still get my emails...LOL;) If I can get the rockers where I want them I don't mind tacking them. I'm fussy and anal about my own stuff, worse when I'm working on someone else's for free... 

Weld them its done all the time.

I doubt if the heads flow what they claim out the box also.

Dave C. wrote:I doubt if the heads flow what they claim out the box also.

Depends on the bench......

and OP $2000 is chump change for good heads nowdays. That barley gets castings in most cases.

Well $2000 is a lot for a guy who works for the coast guard on deck 30 days at a time LOL. They are pretty to look at. He replaced some TF track heats with them

BigRigTech wrote:I'm assembling my best friends 347 and I'm running into troubles with the rocker arm geometry. The new AFR cnc'd heads have the valve locations moved so they came with AFR's adjustable guide plates. The trouble is they inter-lock together way too loose for my liking - as soon as you go to torque them they friggin move and mess up the adjustment and not only that it's damn near impossible to get the alignment right and not have the pushrod rubbing the head. Does anyone else make a better set of adjustable plates? My buddy said he had the same issue with his SBC AFR's and he had to use offset rocker arms to get the roller tips on the valve stems where they should be.

If you have the tips centered and the pushrod almost rubs the head, it's time to clearance the head...
Once it's running and wound up, it WILL be rubbing...
Different guide plates aren't going to change that...

It was close but not rubbing, once he gets home we will get it sorted out. I have the engine here but all the parts yet to be installed are at his place. I have a 347, 302 and a two 7.3L Powerstrokes here right now - my mustang is in here too, my garage is full...LOL

make sure you check the piston to valve clearance real good, sbf AFR's are a pita......

BigRigTech wrote:It was close but not rubbing, once he gets home we will get it sorted out. I have the engine here but all the parts yet to be installed are at his place. I have a 347, 302 and a two 7.3L Powerstrokes here right now - my mustang is in here too, my garage is full...LOL

That's the point....
If this thing is going to be wound tight and they are within 0.030" or so, They will rub...
You be surprised how things move and bend at higher RPM..

i used harland sharpes shaft rockers and had no problems

I here ya on the whole deflection deal with the pushrods.  

what pushrod dia?

TF 6.700", .080" wall. 5/16"

we wanted to step up to 3/8" in ours but the AFR's wont let it happen, went w a .115 wall 5/16 instead. I did use the reg comp no adj gp's and it worked out fine.

Are the thick walled 5/16 heavier or stronger than the 3/8?

Used a few of the afr heads. We just tack weld them together. That is an acceptable way of doing it.

We run very large thick walled pushrods on our turbo motors because of the rpm and spring pressures.