[4dblnkldude]

Disclaimer... I did not build this engine. Kind of in a way looking to settle a bet.
Combo is a 455 .030 over, eagle rotating assembly with SRP pistons, E heads 87cc unported and not touched. 230/520/540 comp hyd roller, scorpion 1.5 rockers, RPM, modded holley, dougs etc. Probably a pretty popular combo, in a 70 lemans. What about would the pushrod length at approximately?

[tooski]

I have a bit different setup. I have a 461 stroker eagle rotating with CC 230/236 570 hyd roller cam Maybe a big diff is I have KRE heads. When I had to change lifters I saw the witness marks on my valve tips. Too close to the intake side. 9.100 pushrods. I installed 9.250 pushrods and the witness trace ended up just about dead center.
On a side note I also have a 406 with KRE heads, and HFT cam. Stock pushrods (9.130) The valve tip trace was centered but wide. A 9.300 pushrod length narrowed it up but moved it a bit out to the exhaust side.
I believe Edelbrock and KRE heads have a thicker deck and require a bit longer than stock push rods.
Easy enough to get an adjustable pushrod and find the suitable length.

[TCSGTO]

Too many variables to make definitive statement but Scorpions take a longer pushrod compared to HS and Comp in my experience. I had to go 9.4” with Comp “S” HR lifters and both 1.5 and 1.65 Scorpion Endurance rockers. Different lifters have different seat heights so it’s best to check.

[steve25]

Even the base circle of the Cam is likely not the same as someone else's Cam to make a comparison with, so like posted above there are too many variables.

Make a adjustable push rod out of a old stock one and find out exactly what you need.

Cut one in half. And drill + tap each end for a 6/32 machine screw that you have cut the head off of and your set to take measurements.

This is all of a 1/2 hour job .

[steve25]

Even the base circle of the Cam is likely not the same as someone else's Cam to make a comparison with, so like posted above there are too many variables.

Make a adjustable push rod out of a old stock one and find out exactly what you need.

Cut one in half. And drill + tap each end for a 6/32 machine screw that you have cut the head off of and your set to take measurements.

This is all of a 1/2 hour job .

[Paul E]

Make / get an adjustable pushrod and check for proper length. Order pushrods, remove Edelbrock heads and ream the guides to proper size as they will be very tight and high probability cause an issue.

[Lee]

10 years ago, I had HR lifters from Comp and from Lunati. There was a 0.300" difference in pushrod length needed for each. More recently, I test fit a set of the new CompCam roller rockers against a set of Crowers - about 0.300" for them as well.

So, somewhere between 8.800" and 9.500", most likely.

[4dblnkldude]

Thank you all. I don't think they were as off as I thought. There is 9.150 pushrods in there. We checked one on Friday night and they are absolutely to short. Could use another .150-.200 or so. Here's what happened, the car was down on power at the end of last year and we diagnosed a bad MSD pickup. The #3 hole was not firing, after the pickup was installed all was good. (or so we thought) Ran it again and did a 12.10 on 7 cylinders. After doing a few little upgrades over the winter the valve covers were removed to put different ones on. Thats when we discovered the #3 intake rocker off and laying in between. The poly lock was in the back of the head with the set screw still in there. So the rocker, pushrod, and roller lifter are all hammered up. I don't think the pushrod was the issue but the "builder" forgot to adjust that rocker in whatever sequence he uses or he didnt tighten down the set screw all the way. Bummer right...

[steve25]

If there’s any good side to look at this from then your lucky it was a intake valve that was not opening and closing.
I have seen situations the other way around and not only is the motor backfiring and catching the carb and air cleaner on fire, but the intake charge in other cylinders that don’t have there intake valve closed yet is getting lighted off, and that makes for hammering rod time.

[steve25]

Here are some observations I have made over the years in terms of push rod length / geometry and the resultant valve lift.

This info was done with Cams of .333” lobe lift or more .( 500” at the valve or more) and both factory 1.5 and 1.65 rockers.
Roller rockers will not follow exactly what I am stating here .

1.5 rockers.

Once you get the push rod length to about .100” of what’s needed for good geometry you will be within .015” of having the stated advertised lift on your cam card.

1.65 rockers.

Once your within .080” of the needed push rod length for good geometry you will be within .010” of the stated valve lift of your cam card, and I fact you might be .005” over that stated lift.

I hope this helps .