Hi,
I am going to change my camshaft to a Comp Cams Xtreme Energy 274/286 with .488/.491 lift and I am wounder if the clearence between piston and valves is enough?
my 383 block is .030" od.
not Top decked
no cut head with 2.08 and 1.74 valves
head number is 516 closed chambers 73.5 cc volym
fel-pro head gasket
stock rods
stock rocker arms
stock pushrods
flat top piston (TRW) without any valve reliefs
//Roland
5 posts
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Piston to Valves clearence
by mopar70 » 28 Oct 2005 17:03
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mopar70 - Frequent Poster
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by dave-r » 28 Oct 2005 18:47
Without knowing the piston height you have no way of telling. You should remove a head and measure where the piston comes to.
However. Most 383s tend to be low on compression. Even with aftermarket pistons. If you have closed chamber heads that indicates to me that the piston height is probably nothing to worry about because otherwise the compression would be very high and you would be using high octane fuel.
Plus the lift on the cam is not that great.
I wouldn't worry about it.
To install a cam correctly you need to use a degree wheel. I have heard recently that some brands of timing sproket are a few degrees out and retard the cam. Check the cam timing carefully and maybe put some modeling clay on a piston top to check piston-to-valve if it is worrying you.
However. Most 383s tend to be low on compression. Even with aftermarket pistons. If you have closed chamber heads that indicates to me that the piston height is probably nothing to worry about because otherwise the compression would be very high and you would be using high octane fuel.
Plus the lift on the cam is not that great.
I wouldn't worry about it.
To install a cam correctly you need to use a degree wheel. I have heard recently that some brands of timing sproket are a few degrees out and retard the cam. Check the cam timing carefully and maybe put some modeling clay on a piston top to check piston-to-valve if it is worrying you.
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dave-r - Grumpy Old Man
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by Follicly Challenged » 14 Nov 2005 15:12
As long as theres no head or block milling as you've indicated, it should fit fine. Best check anyways upon assembly/mock up.
From memory, not good these days, the 516 head should measure approx .750" ? ? , common to all BB iron factory heads, from deck to factory cast "machine target", (flat area beside plug in chamber). I'll check the number and get back at 'ya. I'll also dig you up a valve stem height number, which I've also long forgotten. Makes for some easy determination cautions on the bench as to prior milling/surfacing on heads before mock-up. Sorry, I just ain't worked on any iron stuff for years. You'll still need an average of all 4 chambers on each head, it's just a rudimentary check.
I'll get back to you.
From memory, not good these days, the 516 head should measure approx .750" ? ? , common to all BB iron factory heads, from deck to factory cast "machine target", (flat area beside plug in chamber). I'll check the number and get back at 'ya. I'll also dig you up a valve stem height number, which I've also long forgotten. Makes for some easy determination cautions on the bench as to prior milling/surfacing on heads before mock-up. Sorry, I just ain't worked on any iron stuff for years. You'll still need an average of all 4 chambers on each head, it's just a rudimentary check.
I'll get back to you.
- Follicly Challenged
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5 posts
• Page 1 of 1