Post by dennis on Aug 16, 2005 22:23:19 GMT -5
i have been highly recommend from the chevelle web site board to come to cfm and have my heads ported.
but i have a few q's. hopefully not to long.
i have been porting my own bbc heads since 1993 and my knowledge only comes from books and practice and real track times from my work.
i was wondering if it would be worth it to have such a place as cfm to port my heads for the horsepower level im running ( most the engines i build for myself and race are around 500-650 hp).
im not saying that im a know it all or nothing like that but just for the lower hp motors that are just street driven and see some track time.
one down fall i have about porting heads is that i dont have a flow bench of no means so even tho i try to make things look the same i may differ from runner to runner as far as flow goes.
to give you an idea i what i do is i clean every last amount of casting roughness and casting flash in all the runners, then i use 80 grit paper to rough the intake runners up and 120 to smooth out the exhaust, i dont bother polishing since i have been told it does nothing , i stay off the floor of the intake runners as much as possible, i dont try and change the runners just clean them up, i round the short turn radias as smooth as one can. and i stay away from the long turn radi area in the bowl since only grinding makes a pocket that does nothing for flow, after a 3 angle valve cut i go back in and clean up the ridge that is left in the throat and in the chamber. i open up the throat just under the seats some since most of the heads i do get the bigger valves.
then i have a 20 degree back cut put on the valves. i dont do nothing to change the guide boss i just leave it as cleaned up. one time a machinist cut the guide boss clean out and i noticed the lack of low end power and my times hurt. so that was a bad deal. he missed understood me cause i told him just to cut down the valve guide to the boss.
so i was just wondering i like the idea of having a shop to port my heads because i think they can provide me with more even flow numbers but for the level of hp which this engine i building now will be about 500 to 525 hp is it worth the extra money to ship them off to cfm or do you think the work i do would be good enough.
i guess since i feel like i take the time, and feel like i do a good job in my eyes. i would hate to send my heads off and then get them back and they might be less then what i would have done and feel cheated.
do you offer flow data with each head you do, and would there be personal attention made to my combo that im building to provide me with the best results in tq and hp.
the set of heads i was thinking of shipping off is a set of 049 heads i would send them bare with a new set of ss valves 2.19/1.88 for which they would have to be cut. and ported for my 454 which will run from 2500 to 6500 rpms.
thanks for reading dennis
but i have a few q's. hopefully not to long.
i have been porting my own bbc heads since 1993 and my knowledge only comes from books and practice and real track times from my work.
i was wondering if it would be worth it to have such a place as cfm to port my heads for the horsepower level im running ( most the engines i build for myself and race are around 500-650 hp).
im not saying that im a know it all or nothing like that but just for the lower hp motors that are just street driven and see some track time.
one down fall i have about porting heads is that i dont have a flow bench of no means so even tho i try to make things look the same i may differ from runner to runner as far as flow goes.
to give you an idea i what i do is i clean every last amount of casting roughness and casting flash in all the runners, then i use 80 grit paper to rough the intake runners up and 120 to smooth out the exhaust, i dont bother polishing since i have been told it does nothing , i stay off the floor of the intake runners as much as possible, i dont try and change the runners just clean them up, i round the short turn radias as smooth as one can. and i stay away from the long turn radi area in the bowl since only grinding makes a pocket that does nothing for flow, after a 3 angle valve cut i go back in and clean up the ridge that is left in the throat and in the chamber. i open up the throat just under the seats some since most of the heads i do get the bigger valves.
then i have a 20 degree back cut put on the valves. i dont do nothing to change the guide boss i just leave it as cleaned up. one time a machinist cut the guide boss clean out and i noticed the lack of low end power and my times hurt. so that was a bad deal. he missed understood me cause i told him just to cut down the valve guide to the boss.
so i was just wondering i like the idea of having a shop to port my heads because i think they can provide me with more even flow numbers but for the level of hp which this engine i building now will be about 500 to 525 hp is it worth the extra money to ship them off to cfm or do you think the work i do would be good enough.
i guess since i feel like i take the time, and feel like i do a good job in my eyes. i would hate to send my heads off and then get them back and they might be less then what i would have done and feel cheated.
do you offer flow data with each head you do, and would there be personal attention made to my combo that im building to provide me with the best results in tq and hp.
the set of heads i was thinking of shipping off is a set of 049 heads i would send them bare with a new set of ss valves 2.19/1.88 for which they would have to be cut. and ported for my 454 which will run from 2500 to 6500 rpms.
thanks for reading dennis
