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Anyone running an SBC with H618P/H618CP pistons?

7K views 2 replies 2 participants last post by  v8hed 
#1 ·
This is what I have... H618P pistons 0.025" down the hole. I'm looking for feedback from folks with this same set-up and aftermarket heads. What heads are you running and did you have any problems with dome clearance?

Thanks,
Ian.
 
#2 ·
Ian, you seem extremely reluctant to do this checking yourself for some reason. Go ahead and get the 20 degree heads and check them yourself. At the worst, you may have to use an Isky tool to re-cut the valve reliefs a little in the pistons. No big deal.

No matter what answers you get from others, if you don't check YOUR stuff YOURSELF, you won't have a definitive answer. There are simply too many variables between motors to say whether one guy or another had or didn't have clearance problems. Possible differences are as follows...
Block deck height difference
Rod center to center difference
Piston compression height difference
Block deck to valve seat dimension difference
Rocker arm ratio difference
Camshaft timing events difference

Here's a tutorial from Isky to help you check the clearance properly. Hope this helps. :D
http://www.iskycams.com/camshaft.php

You can rent the piston notching tool for US$40.
http://www.iskycams.com/onlinecatalog.html
 
#3 ·
techinspector1 said:
Ian, you seem extremely reluctant to do this checking yourself for some reason. Go ahead and get the 20 degree heads and check them yourself. At the worst, you may have to use an Isky tool to re-cut the valve reliefs a little in the pistons. No big deal.

No matter what answers you get from others, if you don't check YOUR stuff YOURSELF, you won't have a definitive answer. There are simply too many variables between motors to say whether one guy or another had or didn't have clearance problems. Possible differences are as follows...
Block deck height difference
Rod center to center difference
Piston compression height difference
Block deck to valve seat dimension difference
Rocker arm ratio difference
Camshaft timing events difference

Here's a tutorial from Isky to help you check the clearance properly. Hope this helps. :D
http://www.iskycams.com/camshaft.php

You can rent the piston notching tool for US$40.
http://www.iskycams.com/onlinecatalog.html

Yea, I was just trying to avoid the possibility of purchasing heads that I can't use. But, you're right, there are probably too many variables. I'm getting the heads for a good price (used), so I could probably flip them for what I paid if I can't use them.

I'll clay-up a piston and see what's what when I've got the heads.
 
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