head stud question.

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nickg9785

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Mar 14, 2012
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ok so right now i have arp425 studs and a oringed head with a .010 marine gasket. mods are in sig. truck makes about 80psi of boost. my question is, im thinking about swapping the 425s out for a set or 625s? do you think its worth it or will my 425s be fine with the orings? any input would be great before i buy these things. thanks
 
What are your HP goals? At what boost and at what compression ratio do you plan on making this HP number?
 
id be happy with 7-750. stock comp ratio and i will probably be around 80psi of boost.
 
im planning to run nitrous once i get external gates, you think they will still hold up, its only going to be used for dyno pulls
 
well i just blew my head gasket. leaking between 3 and 4 on the exhaust side, going to pull the head and check the block for flatness. now do i go ahead and put the 625s in or should i pull the motor and go with the 14mm studs?
 
If you're running 80 psi of boost and nitrous you're better off using fire rings as you're already on or past, the recommended max boost for o-rings. You can start with checking the block and head for straightness.
 
I run 95psi daily for the past couple years on 425s torqued to 130# and Orings. But I dont run aggressive timing.
there is a lot more to it than just "max boost". Fire rings are not recommended for street trucks.
 
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im sending the block out to be decked and having the head checked. do you think id be okay to just order a new set of 425s instead of the 625s. the head is o ringed already.
 
I'll assume you had the head decked? now having the block decked, so you are raising compression. If you drop the comp ratio and keep timing more reasonable than 28*, you should be fine @ 80 once the gasket is well bedded in. Going 625 or 1/2" or 14mm would be a better insurance if available to you.
 
yes head was decked when i had it oringe less than a year ago. im assuming the head is still good. but i will check it. theres no one that will orning a head near me, i had to send my head away to be machined last time and would like to avoid doing that again. i would like to put the money somewhere else then buying 625s so if i can get awy with the 425s again i would much rather do that.
 
this will be the 4th time im using them and i think they might be streching. i checked them after i blew my head gasket and they all turne about 1/8 turn at 125lbs
 
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