How much should I mill 317's with 228r cam?
05-08-2012, 11:22 AM
#1
How much should I mill 317's with 228r cam? Im looking to start doing stage 2 upgrades to my car by bumping up the compression and doing headers.The heads are stock with tsp 7.4 rods,228r cam,and pac 1218 springs.
Its cheaper to mill my current heads than replacing them with 243's but I dont know what is the amount that would need to be taken off.And if the heads are milled would I have to change my pushrods and can I still reusue my tsp 7.4's?
Im hoping to gain a solid 30-40rwhp from doing headers and milled heads which is a safe bet.
Its cheaper to mill my current heads than replacing them with 243's but I dont know what is the amount that would need to be taken off.And if the heads are milled would I have to change my pushrods and can I still reusue my tsp 7.4's?
Im hoping to gain a solid 30-40rwhp from doing headers and milled heads which is a safe bet.
05-08-2012, 11:41 AM
#4
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What made you want to run the 228r. I ask this because I was thinking of running that cam on my procharged Camaro. I also have a set of 317 with the same pushrods and springs. You think that would run better than Bobs blower cam?
05-08-2012, 01:10 PM
#5
I choose that cam for because its a good all round cam,easy to tune,makes good midrange,good on gas etc.I couldnt tell you about choosing a cam for a blower setup but for what its worth the 228r cam is ok for this aswell..not the most optimum for a blower but will produce good numbers.
If I add a small supercharger in the future Ill be keeping this cam anyway and have about 6-8psi of boost.Right now my compression ratio is too low the upper rpm power is lacking.
Does anyone still have a guestimate of how much i should mill the heads?
If I add a small supercharger in the future Ill be keeping this cam anyway and have about 6-8psi of boost.Right now my compression ratio is too low the upper rpm power is lacking.
Does anyone still have a guestimate of how much i should mill the heads?
05-08-2012, 02:25 PM
#6
Best way would be to slide the cam in and clay the heads....safe gap is .080" intake and .100 on the exhaust.....figure the space you have now. Then mill till you are close to your clearances.
You should be able to run 11:1 compression on 92/93 pump gas with no problem....I'd also run a .040" mos head gasket.
You should be able to run 11:1 compression on 92/93 pump gas with no problem....I'd also run a .040" mos head gasket.
05-08-2012, 02:57 PM
#7
I was hoping that i could pull the heads off and give them to the machine shop and there would be already a safe number to ask to have them milled.Its a stock lq4 block,heads are stock with the pac 1218 springs and 7.4 rods using stock gasket now. Taking .30-40 off should be ok and maybe a thinner gasket?
I dont have the means of measuring myself,Id get charged an arm and leg to have someone work on my car and pull the heads off and reassemble it when I can pull them off myself atleast.Getting it up to 10.5:1 should be ok for 20hp or so right?
Sorry Im asking alot because i dont dive into the internals.I can swap things in and out no problem but these things are grey area for me lol.
I dont have the means of measuring myself,Id get charged an arm and leg to have someone work on my car and pull the heads off and reassemble it when I can pull them off myself atleast.Getting it up to 10.5:1 should be ok for 20hp or so right?
Sorry Im asking alot because i dont dive into the internals.I can swap things in and out no problem but these things are grey area for me lol.
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05-08-2012, 03:04 PM
#9
BTW... I have a set of ported/milled 317s I ran with my 226/228 .588 .588 114 cam if you are interested. I have zero information on the heads as far as flow numbers/etc... But my ET/MPH for the setup speaks for itself. They without a doubt flow better than a stg 1 Ls6 head... I would put them above a stg 2.5 as well. I'm sure I could have picked up some mid range with an AFR 205 head but it wouldn't have been too far out.
If you are interested shoot me a PM.
They are off the car sitting in the garage. They are assembled ready to bolt on and go.
If you are interested shoot me a PM.
They are off the car sitting in the garage. They are assembled ready to bolt on and go.
05-08-2012, 06:18 PM
#13
Mill heads-$100
New pushrods-$100
And a loss of PTV clearance (probably will still be safe though), and possible intake fitment problems (doesn't happen all the time, but sometimes it does)
Total cost....$200
Sell 317's - gain $100-150
Buy 243's or 799's- $325-350
possibly still able to use same pushrods, don't lose any PTV clearance, and 64cc chamber (Still a smaller chamber than if you milled 317's .030)
Total cost.....$200-225
I'm not getting why switching heads will cost more than milling?
New pushrods-$100
And a loss of PTV clearance (probably will still be safe though), and possible intake fitment problems (doesn't happen all the time, but sometimes it does)
Total cost....$200
Sell 317's - gain $100-150
Buy 243's or 799's- $325-350
possibly still able to use same pushrods, don't lose any PTV clearance, and 64cc chamber (Still a smaller chamber than if you milled 317's .030)
Total cost.....$200-225
I'm not getting why switching heads will cost more than milling?
