After buying an adjustable lenghth pushrod and doing the sharpie on the valve stem check,I end up with a 8.200 length to get the desired mark in the center of the stem.That was way more than I expected.Am I over looking something?Where could this need for extra lenghth come from.I have new canfield 215cc heads with a 1.900 installed spring height,the block deck was milled just enough to square surface.Im using Elgin steel roller tip rockers.I dont think my 401a6lun cam is a small base circle?Could all that stuff just add up?Anyone have similer results with similer combos?Just looking for reassurance I guess.

Originally posted by jm67:
After buying an adjustable lenghth pushrod and doing the sharpie on the valve stem check,I end up with a 8.200 length to get the desired mark in the center of the stem.That was way more than I expected.Am I over looking something?Where could this need for extra lenghth come from.I have new canfield 215cc heads with a 1.900 installed spring height,the block deck was milled just enough to square surface.Im using Elgin steel roller tip rockers.I dont think my 401a6lun cam is a small base circle?Could all that stuff just add up?Anyone have similer results with similer combos?Just looking for reassurance I guess. =
Stock flat tappet is 8.280/9.250, what am I missing here??

Mike, are you talking about BBCs?

My Canfield 215cc heads required 8.050" rods with a small base circle cam, .017" deck, and a .041" gasket. I believe my springs are 1.850".

How do you like your Canfields? I did some cleanup and bowl work, and I think they should run real well. I like their port better than the equivelent Brodix head I saw at a vendor's booth at a swap meet.

By the way, if you've noticed, the intake (I think) valve is slightly moved away from the exhaust. If you run roller rockers down the road, you may have to dimple the valve covers.

7.800 for a stock SBC I believe.I know with my stock pushrods installed,the roller tip on the rocker leaves a wide mark that ends up almost off the stem.I am trying to understand why the length difference from stock is so huge.

Thicker head deck is probably the first reason.

But don't worry about the difference from stock. Just check the length, order them, check again with the new rods, and run with it. The pattern on the stem doesn't lie ;)

JM67, 0.400" is really a lot longer. It doesn't sound right to me.

Does his heads have longer valves than stock and is the valve spring installed height taller than stock? These two things would clearly add some pushrod length to keep the geometry correct.

I have no idea, but I'd imagine a small base circle cam would also drop the lifter down some requiring a bit longer pushrod???

JM,
Sorry about that, with the length you posted yes, I was thinkin (using the term loosely graemlins/clonk.gif ) Rat.
.400 seems pretty long for most applications.
.200- .250 is not that unusual but I do not use Canfields so I don't have a reference to go by.
A 1.900 installed height is normally a pretty long valve in a small block.
As was mentioned, a small base circle could also make a difference.
Do you know the base circle?
If it's like .900 then yes it could very well need a +400 pushrod.

Sorry for the confusion,,, should have read the post a little more carefully & I would have seen the 215cc port :rolleyes:

Thanks for all your replies.After going over the checking procedure a couple times Im pretty confident its right.Just alot of factors added up to .400.Im almost positive the valves are .100 longer,even though that didnt need to be for my application.The cam is a UDHarold grind and although I didnt specify it,may very well be small base circle.I ordered my freakishly long pushrods today.Thanks again for all replies.

1. Did you measure the checking pushrod correctly, including the phantom length caused by the oil hole in the tips?

2. Are these hydraulic lifters that collapsed during the measurement process and added something like .230 to the length?

3. Different rocker designs require different pushrod lenghts--maybe you have some odd rockers?

I know nothing of phantom length.
They are solid flat tappets.The checker measures .400 longer than the stock rod.My rockers are just Elgin steel roller tips.I think all the variables just stacked up on the + side.

jm67, here is a link that might explain phantom lenght measuring pushrod length (http://www.compcams.com/Technical/Products/Pushrods/) . I found this when I was researching how to do the measuring myself. Hope this helps.

I could be wrong, but I believe that diagram (diangram "A") has #1 and #3 reversed. Somebody look and see if I need correcting or not.