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Which head gasket for a 4.280 bore?

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Old 01-24-2013, 04:18 PM
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Originally Posted by blue thunder
i've run them at .035 with good luck but usually look for .038 on a bbc. You just need to be aware of piston rock and other clearances so not to get into trouble. Plus if you don't have a rev limiter that 5200 may turn into a 8k unplanned.

Also what is the IVC angle on the cam you plan to run?
I hope it never goes to 8K - piston to head contact would probably be the least of my problems then!

Not sure what you mean by IVC. It is a custom Marine Kinetics cam - 226*/230* @ .050, 114* LSA, .612 / .596.
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Old 01-24-2013, 04:28 PM
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Originally Posted by Budman II
I hope it never goes to 8K - piston to head contact would probably be the least of my problems then!

Not sure what you mean by IVC. It is a custom Marine Kinetics cam - 226*/230* @ .050, 114* LSA, .612 / .596.
Its 'intake valve close' spec on the cam card. It helps determine how your combo will work. You have lower compression so you wouldnt want a cam IVC angle that bleeds off more compression. Plus it help you decide how exactly to index the cam in to get the best power at the rpm you want it at.
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Old 01-24-2013, 04:39 PM
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Originally Posted by blue thunder
Its 'intake valve close' spec on the cam card. It helps determine how your combo will work. You have lower compression so you wouldnt want a cam IVC angle that bleeds off more compression. Plus it help you decide how exactly to index the cam in to get the best power at the rpm you want it at.
It closes 42.9* ABDC.
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Old 01-24-2013, 04:43 PM
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Originally Posted by Budman II
It closes 42.9* ABDC.
Do you have the seat to seat angle? Or the .004/.006? If not, the calculator below works with .050, its just for boosted apps usually. Just enter 0 for boost. You want you DCR around 8-8.1 which from my quick try of it with you numbers and cam suggested to advance the cam 3* to get a proper DCR. It would be best to have more compression to get the correct DCR number but you work with what you have. You might be fine advancing the cam 3* but Bob M should be the final answer on that.

http://www.rbracing-rsr.com/comprAdvHD.htm

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Old 01-24-2013, 04:52 PM
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It opens at 3.2* BTDC if that will allow you to derive the seat-to-seat angle.
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Old 01-24-2013, 04:55 PM
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Edit to my last post that should help you dial it in yourself with the .050

BTW, I like that cam selection. Should be a good combo if done right.

Last edited by blue thunder; 01-24-2013 at 04:58 PM.
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