should i mill my heads???
06-19-2009, 06:52 PM
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should i mill my heads??? ok so heres what i got:
350 4bolt, 9.1 to 1 CR
speed demon 750 carb
edelbrock air gap intake
JEGS aluminum heads:
197cc/64 cc
2.055 In/1.600 Ex
Comp 282 roller cam:
282/288 duration 230/236 @ 50
lift 510 In/520 Ex
lsa/icl 110/106
so what do you think, should i mill the heads down??(they are not installed yet), id like to raise my CR but i have heard of people sayin that they've milled theyre heads and it made it run worse(which is really odd) but anyway whats your opinion? and what do u think itd raise to if i did?....thanks for any help!
350 4bolt, 9.1 to 1 CR
speed demon 750 carb
edelbrock air gap intake
JEGS aluminum heads:
197cc/64 cc
2.055 In/1.600 Ex
Comp 282 roller cam:
282/288 duration 230/236 @ 50
lift 510 In/520 Ex
lsa/icl 110/106
so what do you think, should i mill the heads down??(they are not installed yet), id like to raise my CR but i have heard of people sayin that they've milled theyre heads and it made it run worse(which is really odd) but anyway whats your opinion? and what do u think itd raise to if i did?....thanks for any help!
06-19-2009, 09:49 PM
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How did you figure your compression? Do you have flat or dish pistons (what the cc on the reliefs), deck height and bore, and head gasket thickness/bore (brand and part number if unsure)? I would probably try a different head gasket if you have some around. A slight increase in compression may not make enough difference to really count though.
06-20-2009, 12:30 AM
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If I remember correctly, you have the GM 330 horsepower crate engine that you were swapping the heads and cam on. It really depends what you want to do. If it were me, I would aim for around 10-10.5:1. It's really hard to give you a direction without knowing the gasket thickness, how far the pistons are down in the bore and the volume of the valve reliefs. Assuming some general numbers (.040", .025" and 10cc respectively) I'd say get the heads down to a 60cc chamber and use Felpro 1094 (.015") or Mr. Gasket 1130 (.018"-.020") head gaskets. That'll put you somewhere in the range I listed above with a good quench distance. That is based on the pistons being .025" down in the bore with a .040" gasket. These numbers are very important for your final descision. The Vortec engine may have the pistons higher in the bore to optimize quench distance. If that is the case you cannot use the thin gaskets or you will run the risk of the piston hitting the head when the engine is running at higher RPM and if the engine already has a thin gasket, swapping in the same type will do nothing to aid your quest for compression. You really need to get the engine broken down and get these critical measurements before you decide on your course of action or any of us can really give an accurate recommendation.
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06-22-2009, 12:15 PM
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well i dont know lol i just really decided not to mess with it, my other question is i had vortecs with a bigger cam than i have now, so now i have a slightly smaller cam in and my new heads have the same 64cc like my vortecs, so i should be fine on pistion to valve clearance right?...it worked with a bigger cam and same size cc so a smaller cam should b for sure ok right?...mabey the cc doesnt matter im just wanting to b sure, i know i could put some checking springs on there and do it, or some soilid lifters the same size but id rather not have to do it....what do u think bout the clearance?....thanks again!
06-24-2009, 12:15 AM
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Honestly, if there's any question.....check it! It's silly to take a chance on damaging the engine to save an hour at assembly time. On that note, you should be ok. If I remember correctly, both cams you used are on the same LSA and this one has less lift and duration, all of which will affect piston to valve clearance.
Oh and if you're still looking for more compression, you can still mill the heads a little and use the traditional Fel Pro gasket (1010) you just won't know if you've optimized your quench distance.
Oh and if you're still looking for more compression, you can still mill the heads a little and use the traditional Fel Pro gasket (1010) you just won't know if you've optimized your quench distance.
06-24-2009, 11:59 AM
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well its not the hour of time that bothers me...its that i dont have the tools to remove springs to put check springs on, so id have to take em somewhere to have them put on and then take it back to have them take them off and so on, or if i didnt do that id have to buy some solid roller lifters to check it....thats why i wanted peoples opinion to see if itd proly be ok...also i called the jegs tech line and talked to them about it, and they said i wont have any clearance issues so i may just go for it, i duno
