906 head capabilities?

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PRH said:
I wasn’t there, and never say never…….. but…….
Since those heads have valves that are .350+ longer than factory heads, then any pushrods designed to work on factory heads…….. in theory would be way short on your heads.
But………mix n match rockers, lifters, cam base circle, etc…….. and you need what you need.
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Yea I thought it was strange how much shorter the pushrods were coming out to be but the pushrod tool I had came out consistent on all the push rods.
 
PRH said:
Two different sets of pushrods?
The ones in the first pic are showing obvious contact with the head, and the pushrod cups are black.
The bent ones have pushrod cups that are more of a silver color.

View attachment 1716149408

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Yes so it had 1 bent rod and I tried to order just one but they were on back order and had to order a full set but they were the same pet number. We swapped from a 750 to a 1050 carb and had a big back fire through the carb and thought that’s what had caused the 1st push rod to bend and the 440 source rockers failed as wel. I just clicked reordered.
 
Like I said……… that roller valvetrain stuff is pretty unforgiving of not having things being right.
 
RustyRatRod said:
A lot of them are because the red x is so close to the reply button.
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Also I 'm right handed and tend to scroll with my right thumb on the right side of the screen where the red x is. Too bad they couldn't move those options to the center of the screen and or add an "are you sure" step to it. Or just get rid of it. If you disagree you can say so in a post along with why you politely disagree.
 
PRH said:
I wasn’t there, and never say never…….. but…….
Since those heads have valves that are .350+ longer than factory heads, then any pushrods designed to work on factory heads…….. in theory would be way short on your heads.
But………mix n match rockers, lifters, cam base circle, etc…….. and you need what you need.
Click to expand...
Wouldn't roller lifters need shorter pushrods? And longer valves need longer pushrods? In general.
 
I may have missed where you said what you were doing with this car. Street, street strip, full time drag race. But even without knowing I’m going to repeat what I said earlier. You don’t need a 380 cfm capable flowing head on this engine. Good luck with your fix but I would sit down and think things over.
 
My .02 is, he already has the heads, and the expensive rockers to go with them.
Aside from some clearancing for the intake pushrods, there isn’t any extra work involved in using these heads as anything else that will be used with the cam he has………other than some TF heads with the roller spring package(and his rockers won’t work with those).
And whatever is causing the nearly zero P/V clearance on the exhaust, but tons of clearance on the intake……..won’t be solved with a head swap.
If the OP’s heads are the unported version they’ll flow in the 310-320 range……..which should be fine for a street/strip 470.
(Actually, the cnc ported std port version would be fine as well)

What I’m seeing appears to be:
-cam is probably in wrong*
-pushrod tunnels need more clearancing
-valve springs completely wrong for the cam

* if the cam is degreed in properly, and the clearance is still next to nothing on the exhaust, the easiest solution would be to use a shorter duration cam.

The motor needs to be gone over by someone who knows what to look for, and what parts should be used to make it as trouble free as a combo like that can be.

More related reading:
Pro Comp BB Victor CNC heads
 
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92b said:
Wouldn't roller lifters need shorter pushrods? And longer valves need longer pushrods? In general.
Click to expand...

The solid roller lifter pushrod seat heights vary quite a bit, brand to brand, and sometimes even within the same brand for different part numbers.
But not always…….
Comp SFT lifter 2901, seat height = 1.79”
Comp Roller lifter 829, seat height = 1.79”

As I said in that post, when you mix n match parts(heads, rockers, lifters)…..get out the checking tool and see what your combo requires.
If someone has something available off the shelf, great.
 
GTX JOHN said:
That cam is insanely huge for anything that will ever
see the street longer than it takes to get on a trailer.
it sounds like your Valvetrain may not accommodate the lift
on your camshaft.
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The duration is very large for a street car, the lift isn't.

I agree as to the potential cause of the failure though.
 
92b said:
Wouldn't roller lifters need shorter pushrods? And longer valves need longer pushrods? In general.
Click to expand...
Longer valves need longer pushrods in a magnum (read: chevy-like) application, stud mount rocker.
If you have a fixed location shaft rocker, you would need to move the shaft, or use SHORTER pushrods, (and the geometry would suck.)
 
“In the context of this thread”, and relating to the heads the OP is using(Victor copies), the heads use valves that are roughly 3/8” longer than factory heads.
The rocker shaft saddles are relocated accordingly to accommodate the longer valves.

If you removed factory heads from an engine that had the correct length pushrods in it, and bolted the Victor type head in its place, the engine will now require longer pushrods……..and not just a little longer.

The same situation is also true with B1, B1-BS, Bulldog, Indy, Chapman stage 6(original stage 6 use stock length valves), or TF heads.
 
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