Cam selection

Zfan

Member
I have got a friend that is unhappy with his current cam in his ride. I told him about you Grumpy and he asked me to give you his info and to see if you had a hyd. roller cam you would recommend. The car is a 1974 Jensen Healy weight approx. 2900 lbs with him in it. The transmission is a built 700r4 with a 2600-2800 stall converter, rear end is a ford 9" with 3.70 gears and a 26" M/T drag radial.

Engine specs are as follows:

350 sbc ZZ4
9.7 to 1 compression static
Forged crank
PM rods 5.7
Hyper. pistons w 4 valve relief.
block not decked .015 in the hole.
.040 head gaskets
Edelbrock RPM heads with 64cc chambers and 170cc runners.
Edelbrock hyd. roller cam 234/244 at .050 488/510 lift with a 112 lobe sep.
Comp 1.50 roller rockers
GM performance intake, dual plane, like a Edelbrock rpm.
650 holley 4150 series dp carb
block hugger headers 1 5/8 primaries with 2 1/2 collectors.

Car is a cruiser but see's a lot of 1/8th and 1/4 mile runs. He doesn't like this cam, I think he needs to change it out and was wondering what your thoughts were.

Appreciate your input,
Mike
 
It would help, if I knew WHAT he didn,t LIKE about the current cam?
( I can guess that hes less than impressed with the low rpm tq due to the cam duration and the high rpm fades fast due to the small port size, hydraulic valvetrain limitations and small carb, but it probably runs nice in the 4000rpm-6000rpm band)

and what the max lift on the valve train clearances are?
whats the edelbrock head part numbers and spring load rates..

at what rpm he launces and shifts at. and any other info he might care to provide.
 
Grumpy,

He stated the cam was dead down low and felt flat from 5k on up to 6k. He launches at just idle to just off idle as that's what seems to get him the best 60 ft's. He would like to shift at approx. 5,500 rpm's, no more than 5,800. He doesn't know the exact model number of the RPM heads but does know that the seat pressure is 130 and open is 340 with max lift at .600. I gave you the wrong lift numbers on the current cam, the are .539 intake and .548 exhaust.

He wants a smaller cam with maybe 110 lobe seperation, but 112 would be ok too. He may spray a small shot of nitrous in the future, I am still trying to get over to the dark side. I def. think a small cam would be ideal as his compression is weak for a cam like that. I have learned to error on the small side rather than big.

Thanks,
Mike
 
this is the SMALLEST CAM ID suggest, and its the best match to the rest of the combo,
RR-265/272 2000-6000 .485 .000 265° 217° 112°
Good mid-range power. Good vacuum & good idle. 3.23-3.70
axle ratio. 9.5-1.5:1 compr. Computer compatible with stage 1
chip. Stock converter. Up to 650 CFM Carb.

next larger isky

RR-272/282 2500-6400 .505 .000 272° 225° 112°
THIS is the LARGEST ISKY cam ID suggest, it will most likely NOT require alot of clearence work and new springs

http://www.iskycams.com/onlinecatalog.html

why not call isky, but ID suggest something close to this, if your still set on max power vs driveability

another option, that will require changes in the valve train

THIS is the LARGEST ERSON cam ID suggest, it will most likely WILL require alot of clearence work and new springs , on the plus side it produces killer upper mid rpm range power, and HAS a good deal more lift and power potential

Erson:
E119847, Duration: 226/234, LSA 112, Lift: 584/584

http://www.pbm-erson.com/store.php?catId=692&parent=327

obviously the ERSON has a great deal more power on the upper rpm but it still lacks the low rpm tq to a great degree and your clearances may be a huge problem



yes you could go to the next larger isky cam, to get closer to the ersons power and still might use the current springs, but discuss it with, erson and iskys tech guys, those heads, carb, intake and headers your using are designed , more for the 1500rpm-5500rpm band, so matching the milder cam should help noticeably, PERSONALLY,If you go with the milder ISKY ID install it at the split overlap vs the dot-to-dot which will retard it 4 degrees,lower the tendency to get into detonation and raise the power band about 200rpm, and thats the best match to your current combo


READ THRU THESE CAREFULLY
http://www.compcams.com/Community/Artic ... 2026144213

http://www.popularhotrodding.com/tech/0 ... index.html

http://www.hotrod.com/techarticles/113_ ... index.html

http://www.circletrack.com/techarticles ... ation.html

viewtopic.php?f=52&t=1070

viewtopic.php?f=52&t=480

viewtopic.php?f=52&t=2782&p=7215&hilit=+overlap#p7215

viewtopic.php?f=52&t=90

viewtopic.php?f=52&t=2782&p=7433&hilit=+overlap#p7433
 
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