[i82much]

I am curious what people typically use for valve lengths and installed height in the older Edelbrock round port heads. I am running a hyd roller with these springs at 1.9 installed height:

https://www.summitracing.com/parts/tfs-16911-16

Just reading the forum, seems like people tend to run shorter valves and springs with closer to 1.8 installed height. I wonder why the original builder set the heads up this way?

[ID67goat]

I will have to check my old Edelbrocks to see how they are setup. Do you have the 72 or 87cc heads? Also what lift are you running?

[i82much]

87 cc heads and almost .600 lift (old faithful 1.0 with 1.5 rockers). thanks!

[steve25]

Well all that matters is to be in the ball park for the needed spring pressure and then to have push rods that give good geometry..

What the heck is your seat pressure at 1.9?

The spec in that listing gives every detail but that!

[i82much]

Originally Posted by steve25

Well all that matters is to be in the ball park for the needed spring pressure and then to have push rods that give good geometry..

What the heck is your seat pressure at 1.9?

The spec in that listing gives every detail but that!

127 ... it's lower down the page under the "applications" section.

It just seems like most of these are set up the same way but mine were done a little differently so was curious as to whether there was any reason to do so. It seems like there are more spring options if you use a lower installed height.

[Steve C.]

A FWIW, below is what I was told by Edelbrock in 1999 regarding their valve length used at the time on round port heads that they shipped assembled.
Their target installed height was 1.800". I presume the same today.

#6057 head (87cc)- 5.093" intake / 5.110" exhaust
#6059 head (72cc)- 5.213" intake / 5.230" exhaust

I bought the Performer RPM heads with advertised 72cc combustion chambers, semi-machined pair P/N 6050 at the time.
Today they are on my current 505 set up for solid roller springs at 1.900"-1.910" installed height.
The current intake valves are custom Ferrea Competition Plus hollow stem stainless steel with 2.150" diameter and 5.350" length.


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[Skip Fix]

Theoretically both 72 and 87 have a 1.8 IH. Two of mine had been a hair shorted 1.775

[Steve C.]

Some sources state a installed height of +/- 0.020 inches is accetable.



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[i82much]

So does this mean my valves are probably .1 inch longer than the Edelbrock spec?

[Steve C.]

What can come into play in regards to the overall installed height? Obviously the valve length.

Valve spring retainer fit ?
Valve spring shims ?
Valve stem height ?

Out of my league

steve25 chime in !


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