Pushrod Length Check..WTF am i doing wrong?

If the block is stock and not squared from the mains you need to measure the lifter preload side to side and front to back. Shoot for the max .030 preload max.. less is fine. JW used .030" it so I would go with that. The last block I had machined was .018" out on the pass side from front to back. You need to establish a proper valve tip wear pattern 1st however. Then worry about preload. Very important. Like JW says it can cause revebility issues and it takes alot of friction of those valves to make that loss happen. not good. This is why it's so important. You don't want the valve stem rubbing on the guide as it also causes rapid guide wear, when that happens it will affects the valve not to seal on the 45*angle on the V/J on the head.
Ray

 

Have you set each of the 4 corner pistons at top dead center and measured to see how square the deck is? I would start there.

 

Technically speaking your should use the same piston/rod in all 4 corners to verify first. Then check with the correct pistons/rods know what difference exists, if any.

 

Just get a set of adjustable 5/16" pushrods and be done with it. There's way too much over thinking this already. It barely costs more than a set of good normal non-adjustable pushrods and they will make up for any machining/cam base circle changes and allow for the correct preload of every lifter. As previously said the only way to change the valve tip pattern is to change the valve tip height or shim the rockers up. If your rocker tip favors the rocker arm stand side already then you need taller valve stem height because shimming the rockers will just make it worse. Possibly lash caps could be used too. Unless it is out of wack considerably or you're going over 6000 rpm noticeably then you should have no problem. Thousands of guys have been running Buick V8's without ever worrying about the problem.

I've used adjustable pushrods for 35+ years with no problems and I'm sure others have done the same. I've bought some new and all but new sets right off this board for usually a good deal. You could also use the 3/8" pushrods but the 5/16" give better clearance and will work fine unless you have very heavy spring pressure.

http://www.taperformance.com/proddetail.asp?prod=TA_1428

I run the Pro Magnum lifters typically at something like 1/8th turn which is only a few thousandths of preload for max rpm but I have also set them at .030" preload and they run very quiet. Again it depends on what kind of rpm you plan on hitting. However the older "Magnum" lifters are not the "Pro Magnum" lifters which run the usual .030" or so preload. You can tell the Pro Magnum because they have a special sheet metal cup retainer that looks different from usual c-clip or wire retainer.

http://www.jegs.com/images/photos/200/249/249-858-16.jpg

I just wanted to add that if your are using a hydraulic lifter to do the valve tip checking then it probably isn't right because the lifter will almost have to compress some although the Pro Magnums do hold up pretty well but if they are not fed oil pressure sooner or later the spring will compress it. I almost hate to add this because I've said it before but I may as well: You're worried about this, as far as I'm concerned after looking at the picture, insignificant "problem" and yet that camshaft is still in the engine? There's way more power to found in a cam change to a correct cam then playing with the valve tip height. Just sayin'

 

Or better yet blueprint the block when you start the engine build and square off the block at that time making the deck perpendicular to the crank main journal...

 

Obviously.

 

shimming the pedastals is what we did back in the 70's racing nhra stock. you couldn't use adjustables. but shimming is no good. the mating radii are not mating anymore. it now make the shaft bolts and shafts breakable and also makes the pushrods into 's'.
been there, done that

 

How does changing the height of the pedestals by ~0.015 create all those problems?

 

The mopar camp has that covered. These shims are ultra soft aluminum.http://www.manciniracing.com/rocshafshim.html
I used these 8 yrs ago on a 440. Still runs strong. But the Mopar has 5 pedestals the Buick 455 has 4. They come in sets of 10.
I built many engines since 1980. I build an engine every year. Buick chev and mopar. With the first engines I would rebuild early on the first thing I noticed the engines guide wear was excessive. Then I noticed the valve tip wear pattern was way out. Way over centered. You need it bang on.
If running over 280 lbs over the nose I would recommend TA hd shafts and the 430 hold down ass. and studs.
Ray

 

I wrote a detailed expanation in another thread: "TD Rollers" 3/19/16, post #15.

Larry