MadMarv
Jun 7th, 04, 7:46 PM
This has probably been addressed before, but the search function always seems to turn up stuff I'm looking for when I'm not looking for it, then when I want to read it, I can't find it.. heh.
I have a couple questions about this. First, some people have told me my heads are "too big," as in intake runner size with engine size, rpm, weight of the car, and intended useage.
So wouldn't porting them exaggerate this "too big" condition? Or do I have a mistaken conception of what head porting is or should be?
Second, what does this usually cost? And if you don't want to ship heads is there really any way to figure out if the person you might be dealing with knows what they are doing? New England isn't SoCal or whatever...
I have a set of "320cc" dart heads (I don't think dart makes them anymore), that I am *unsure* as to whether they have been touched yet, and the guy who did my cam swap has not been returning any phone calls, and he said something about the heads and may have even flowed them, but I am again, not sure about this. Its a 6500 (max) rpm 462, solid roller 287/291 256/260, dual plane, holley DP.
I am thinking of having this done, depending on what cost it is, and then adding a shim type or otherwise thin type .020 or .022 or .018 whatever I can find head gasket, and if piston to valve still allows for it, shave the heads again. If my math is right and I used Pat's DCR calc right, a .020 gasket puts me in the 10.5 range, that and about a bit more than 1cc off each chamber puts me at 10.7, or and around 8.3 DCR.
Someone with spare time want to fill in the gaps for me?
Right now I am running 10.14:1 CR and 7.9 DCR. The only thing I am guessing on is the "head gasket bore."
Otherwise the data I have is this
4.282 bore
4.00 stroke
deck .002
gasket .039
head CC 116.5
dome 23
--
and with my "gasket bore" guess I come up with 10.14.
The guy who redid the engine 1.5 years ago rounded up to 10.15:1.
Cam is 287/291 256/260 112LSA 104.75 ICL
rod length is 6.385
So I was thinking a little compression boost and some port work, but port work is still one of those black art things for me, like torque converters...
matt
I have a couple questions about this. First, some people have told me my heads are "too big," as in intake runner size with engine size, rpm, weight of the car, and intended useage.
So wouldn't porting them exaggerate this "too big" condition? Or do I have a mistaken conception of what head porting is or should be?
Second, what does this usually cost? And if you don't want to ship heads is there really any way to figure out if the person you might be dealing with knows what they are doing? New England isn't SoCal or whatever...
I have a set of "320cc" dart heads (I don't think dart makes them anymore), that I am *unsure* as to whether they have been touched yet, and the guy who did my cam swap has not been returning any phone calls, and he said something about the heads and may have even flowed them, but I am again, not sure about this. Its a 6500 (max) rpm 462, solid roller 287/291 256/260, dual plane, holley DP.
I am thinking of having this done, depending on what cost it is, and then adding a shim type or otherwise thin type .020 or .022 or .018 whatever I can find head gasket, and if piston to valve still allows for it, shave the heads again. If my math is right and I used Pat's DCR calc right, a .020 gasket puts me in the 10.5 range, that and about a bit more than 1cc off each chamber puts me at 10.7, or and around 8.3 DCR.
Someone with spare time want to fill in the gaps for me?
Right now I am running 10.14:1 CR and 7.9 DCR. The only thing I am guessing on is the "head gasket bore."
Otherwise the data I have is this
4.282 bore
4.00 stroke
deck .002
gasket .039
head CC 116.5
dome 23
--
and with my "gasket bore" guess I come up with 10.14.
The guy who redid the engine 1.5 years ago rounded up to 10.15:1.
Cam is 287/291 256/260 112LSA 104.75 ICL
rod length is 6.385
So I was thinking a little compression boost and some port work, but port work is still one of those black art things for me, like torque converters...
matt