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Ristow wrote:the offy will work very nice in a car with a manual transmission. it's a split plenum,so the cylinders see just half the carb,like a dual plane. the runners are very short on the offy however.
i have one on my 9.5cr 401. performer cam,but with 1.7 ratio roller top rockers. it's runs very nicely. i have a 580cfm holley on it. with 3.31 gears,automatic transmission and 33" tires,i have power at the touch of the pedal.
you may want to up the ante on the cam,with the 4 speed,and lighter weight of the car. it'll certainly be strong off idle with the cam you have.
Thanks for the reply. I was thinking that a hotter cam might be neede to take advantage of the intake rpm range. Maybe something in the neighborhood of 215-220 degrees duration at .050. I don't want the car to be sluggish off idle, and I wasn't sure how far I could go before I hit that point. Also, have you or anyone here tried a Rebel Machine intake? I have one of those too. Not sure which way to go. Thanks.
if you're on the fence between cams,always go with the smaller one. so keep what you have for now,it'll run strong.
i have the 4 hole copy of the machine intake. it runs fine,revs as hard as i want to go. i have a 5600rpm governor in my GW,so my shift points are higher than the stock automatic,that engine revs willingly. no comparison to the "sonic" intakes as far as flow loss over a performer.
run the offy.
It's like you're unraveling a big cable-knit sweater that someone keeps knitting...and knitting...and knitting...and knitting...
Ristow wrote:if you're on the fence between cams,always go with the smaller one. so keep what you have for now,it'll run strong.
i have the 4 hole copy of the machine intake. it runs fine,revs as hard as i want to go. i have a 5600rpm governor in my GW,so my shift points are higher than the stock automatic,that engine revs willingly. no comparison to the "sonic" intakes as far as flow loss over a performer.
run the offy.
My plan was to try the Offy intake with no other changes, and to take it back off if I felt the need for a bigger cam. I just wanted to get your opinion on that intake's low end torque. The Machine intake is different from the 4 holer, not only from the open divided plenum, but also the sharp edges are radiused going into the runners. It is a much smoother look under the carburetor going into the runners.
One other question and I'll leave you alone. Do you think that the 1.7 rockers help with the performer cam? I guess that it adds about .030 lift.
i think they add flow over the valve for sure. how much power? can't say. but it's free lift,without affecting advertised duration,and negligible affect on duration at .050 thou.
yah,the machine intake is very close to the R4B i think i have read. so it'll flow even better. i thought the 4 holer had the same runner contours. maybe not.
It's like you're unraveling a big cable-knit sweater that someone keeps knitting...and knitting...and knitting...and knitting...
Ristow wrote:i think they add flow over the valve for sure. how much power? can't say. but it's free lift,without affecting advertised duration,and negligible affect on duration at .050 thou.
yah,the machine intake is very close to the R4B i think i have read. so it'll flow even better. i thought the 4 holer had the same runner contours. maybe not.
I have had an R4B, and it sits about an inch or so higher than the Machine intake. AMC said in their high performance booklet , Performance American Style, that the Machine intake was "superior to the R4B from 3,000 to 5,500 RPM." I don't know if it is or isn't, but it looks very different in the plenum area than the 4 holer, although the overall height is the same. The transition area into the runners has very sharp edges in the 4 holer, and the Machine is rounded off very smooth where the plenum enters the runners.