How do you determine if a head will work well on a weak cam?
07-04-2004, 04:44 PM
#1
Race Director
Thread Starter
How do you determine if a head will work well on a weak cam?
I'm comparing the 882 heads against the AFR 195s.
Let's assume an L-48 cam (195/202 duration, .390/.410 lift)
AFRS
Lift Int Exh
.2 132 108
.3 198 156
.4 240 178
333882
Lift Int Exh
.2 125 109
.3 175 135
4 204 141
It seems to me like the AFRs would outperform them, even though they are REALLY large intake ports (195cc) versus 151 cc on such a small cam. My plan is to drop the AFR on these motors and (maybe) upgrade the cam - I just want to get a little extra power. The 195s are going to go onto a roller block in the future...
What do you guys think?
-Steve
Let's assume an L-48 cam (195/202 duration, .390/.410 lift)
AFRS
Lift Int Exh
.2 132 108
.3 198 156
.4 240 178
333882
Lift Int Exh
.2 125 109
.3 175 135
4 204 141
It seems to me like the AFRs would outperform them, even though they are REALLY large intake ports (195cc) versus 151 cc on such a small cam. My plan is to drop the AFR on these motors and (maybe) upgrade the cam - I just want to get a little extra power. The 195s are going to go onto a roller block in the future...
What do you guys think?
-Steve
07-04-2004, 05:23 PM
#2
Race Director
Re: How do you determine if a head will work well on a weak cam? (Pacin'California)
Steve,
The key to any engine combo is putting together parts that match up well w/ each other. You need to have enough cam lift/duration & sufficient compression in conjunction w/ that to really utilize heads like the AFR 195s. With your current cam I honestly don't think it's worth the effort & I would wait until I was ready to step up the cam at the same time. Then you'd need to make sure your combo produced enough cylinder pressure to keep the motor from being lazy. It's a balancing act big fella.
Then, of course, you still need to be aware of the pending legislative changes that could extend smog testing for your car- something that could limit your choice of cams, as you well know. Wish I could offer more encouragment. Maybe some of the other folks will have differing opinions.
The key to any engine combo is putting together parts that match up well w/ each other. You need to have enough cam lift/duration & sufficient compression in conjunction w/ that to really utilize heads like the AFR 195s. With your current cam I honestly don't think it's worth the effort & I would wait until I was ready to step up the cam at the same time. Then you'd need to make sure your combo produced enough cylinder pressure to keep the motor from being lazy. It's a balancing act big fella.
Then, of course, you still need to be aware of the pending legislative changes that could extend smog testing for your car- something that could limit your choice of cams, as you well know. Wish I could offer more encouragment. Maybe some of the other folks will have differing opinions.
07-04-2004, 05:31 PM
#3
Team Owner
Re: How do you determine if a head will work well on a weak cam? (Pacin'California)
Steve - Yes, it would run better with even with the existing cam.
The problem is: Do you want to order AFR heads with 1.26 inch diameter springs which would be H-flat cam friendly and incurr the addition costs of spring and retainer again later when you move up to a real cam?
The other problem with AFR heads is the large cc combustion chambers. So you have the additional cost when you buy them of having them flat milled to more pwerful 62-64 cc's.
Once your clear down to the head replacement on an engine block your very close to also very easlily change the cam.
The problem is: Do you want to order AFR heads with 1.26 inch diameter springs which would be H-flat cam friendly and incurr the addition costs of spring and retainer again later when you move up to a real cam?
The other problem with AFR heads is the large cc combustion chambers. So you have the additional cost when you buy them of having them flat milled to more pwerful 62-64 cc's.
Once your clear down to the head replacement on an engine block your very close to also very easlily change the cam.