Camshaft Ideas?
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From: Whiteland Indiana
Camshaft Ideas?
I have a 1968 Vette, 427 with an M-21 4 speed and 4:11 rear end. I am in the processes of freshening up. I am currently running Seal Power L-2300F .030 over pistons, stock 3872702 closed chamber oval port heads, Crane #134242 H-286-2 camshaft, stock exhaust manifolds, and an Edelbrock AVS 800 carb. Am looking for some ideas on whether to keep the existing hydraulic cam or go to something else. Any ideas or good luck with solid lifters??
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The compression is 9.86 :1 and the Crane cam specs are as follows:
LIFT
Intake @ cam 314
Exhaust @ cam 325
Cam Timing
Tappet @ .0042
Intake opens @ 34 BTDC and closes @ 72 ABDC with 286 ADV Duration
Exhaust opens @ 83 BBDC and closes @ 33 ATDC with 296 ADV Duration
Cam Timing
Tappet at .050
Intake opens @6 BTDC and closes @ 40 ABDC Max Lift 107 226 Duration
Exh. opens @55 BBDC and closes @1 ATDC Max Lift 117 236 Duration
LIFT
Intake @ cam 314
Exhaust @ cam 325
Cam Timing
Tappet @ .0042
Intake opens @ 34 BTDC and closes @ 72 ABDC with 286 ADV Duration
Exhaust opens @ 83 BBDC and closes @ 33 ATDC with 296 ADV Duration
Cam Timing
Tappet at .050
Intake opens @6 BTDC and closes @ 40 ABDC Max Lift 107 226 Duration
Exh. opens @55 BBDC and closes @1 ATDC Max Lift 117 236 Duration
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From: Corsicana, Tx
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You could do a LOT better than that cam in your engine. It has a lot of adv duration for the amount of .050 duration you have. That means generally poorer low speed power and driveabilty for the amount of power produced.
I've run what seems like a gazzilion different cams through my old 427..so I can give you some help.....but please tell us more about how you drive, are solid lifters an option...will it ever have headers etc etc etc. Define your idea of street manners.
A nice little solid flat tappet will rock!!
And there hasn't been a big block made that doesn't like at least .600 lift!!
JIM
I've run what seems like a gazzilion different cams through my old 427..so I can give you some help.....but please tell us more about how you drive, are solid lifters an option...will it ever have headers etc etc etc. Define your idea of street manners.
A nice little solid flat tappet will rock!!
And there hasn't been a big block made that doesn't like at least .600 lift!!
JIM
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From: Whiteland Indiana
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I drive the car almost daily in the summer and run it fairly hard. Normal running at 55-60 with time I run 75-80 on the highway (4:11 gears). have run it on the 1/8th mile and would like to run the 1/4 mile next year. I don't plan on installing headers as I have been trying to keep the stock look in the Vette. Has no A/C and solid lifters is an option I am leaning towards. Currently getting 11-12.5 MPG which does not matter because the fun factor is way up there!!
Last edited by james.frazita; Jan 6, 2007 at 03:08 PM.
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From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
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With gearing like that...you can easily use something that is happy to 6500 rpm or so. One of the best street cams I ever used in my 427 was the old Comp 288 street roller. It idled clean with a nice lope, never broke stuff, peaked HP at 5850 (423 RWHP) yet was still making 417 RWHP at 7000 rpm. It had an incredible power range for what it was. Below is a new cam design that Harold Brookshire has put together. He designed the original High Energy cams for Comp...owned Ultradyne for years and then designed the new VooDoo cams for Lunati. he now has his own company again. He has specifically designed this flat tappet to outperform the Comp roller. So that means a LOT less cost and complexity to get better performance! You might check with him at
brookshire@panola.com
I've finally designed something, now I just have to make it......
A solid flat tappet replacement for the Comp Cams CB-288a-R10 their 11-692-8------
CB-288A-R10 288@.015 246@.050 158@.200 .622" valve lift 38-70-78-30
UDHarold's 285@.015 249@.050 161@.200 .618" valve lift 35-70-74-31
Their cam sells on their web site for $363.67, and the -8 in the part number means it IS NOT a steel billet. Lifters cost a good amount, too.
My cam will be a standard high-quality proferal cam--what solids have been made of for 30 years--and will cost around $168.75. Good Americian-made mechanical lifters are available at less than 25% the cost of solid roller lifters.
My cam stays .0176" away from the edge of the lifter, and I have had other cams that get closer to the edge go 100,000 miles on the street. The seating velocity is the same I have used on those 100,000 mile cams. Valve lash on mine is .018", on the Comp .020".
Because of changes in oil quality over the past 10 years, I would recommend using a lot of caution in breaking in ANY flat tappet solid or hydraulic cam.
The Comp Cams is symmetrical, mine, as always, is unsymmetrical. Look at the timing differences at .015"---My cam has a 4* longer power stroke, meaning more torque into your crank at ALL rpms, and a 3* later intake opening point, for less reversion and higher port velocities, again at ALL rpms.
At .050" and at .200", my cam is 3* fatter---Not only is it filling the cylinder faster, it has MORE time to do it.
The result---MORE POWER everywhere.
Now to get you guys some made......
Harold"
Another cam that I used to really like was the old Crane 134761. It ran very strong way back when,,,,but the new *Harold* cam would spank it overall I'm sure.
Part Number: 134691 Grind Number: F-290-2 (REPLACES CC-290A)
Engine Identification:
Start Yr. End Yr. Make Cyl Description
1967 Up CHEVROLET 8 ROUGH IDLE, PERFORMANCE USAGE, GOOD UPPER RPM HP, BRACKET RACING, AUTO TRANS W/ 3000+ CONVERTER, 4200-4600 CRUISE RPM, 11.5 TO 12.5 COMPRESSION RATIO ADVISED. BASIC RPM 4200-7200
Engine Size Configuration
396-454 C.I. V
Valve Setting: Intake .026 Exhaust .026 HOT
Lift: Intake @Cam 3412 @Valve 580 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 3528 @Valve 600
Rocker Arm Ratio 1.70
Cam Timing: TAPPET @.022
Lift: Opens Closes ADV Duration
Intake 39.0 BTDC 71.0 ABDC 290 °
Exhaust 84.0 BBDC 36.0 ATDC 300 °
Spring Requirements: Triple Dual Outer Inner
Part Number 99896
Loads Closed 150 LBS @ 1.900 or 1 29/32
Open 428 LBS @ 1.350
Recommended RPM range with matching components
Minimum RPM 4000
Maximum RPM 7500
Valve Float 8100
Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 23.0 BTDC 53.0 ABDC 105 256 °
Exhaust 68.0 BBDC 18.0 ATDC 115 266 °
Anyway there's a couple of ideas of where I'd be looking at. They are both solid flat tappets. I'd use the lifters with the EDM hole to lube better and then go through all the initial steps to break it in properly.
JIM
brookshire@panola.com
I've finally designed something, now I just have to make it......
A solid flat tappet replacement for the Comp Cams CB-288a-R10 their 11-692-8------
CB-288A-R10 288@.015 246@.050 158@.200 .622" valve lift 38-70-78-30
UDHarold's 285@.015 249@.050 161@.200 .618" valve lift 35-70-74-31
Their cam sells on their web site for $363.67, and the -8 in the part number means it IS NOT a steel billet. Lifters cost a good amount, too.
My cam will be a standard high-quality proferal cam--what solids have been made of for 30 years--and will cost around $168.75. Good Americian-made mechanical lifters are available at less than 25% the cost of solid roller lifters.
My cam stays .0176" away from the edge of the lifter, and I have had other cams that get closer to the edge go 100,000 miles on the street. The seating velocity is the same I have used on those 100,000 mile cams. Valve lash on mine is .018", on the Comp .020".
Because of changes in oil quality over the past 10 years, I would recommend using a lot of caution in breaking in ANY flat tappet solid or hydraulic cam.
The Comp Cams is symmetrical, mine, as always, is unsymmetrical. Look at the timing differences at .015"---My cam has a 4* longer power stroke, meaning more torque into your crank at ALL rpms, and a 3* later intake opening point, for less reversion and higher port velocities, again at ALL rpms.
At .050" and at .200", my cam is 3* fatter---Not only is it filling the cylinder faster, it has MORE time to do it.
The result---MORE POWER everywhere.
Now to get you guys some made......
Harold"
Another cam that I used to really like was the old Crane 134761. It ran very strong way back when,,,,but the new *Harold* cam would spank it overall I'm sure.
Part Number: 134691 Grind Number: F-290-2 (REPLACES CC-290A)
Engine Identification:
Start Yr. End Yr. Make Cyl Description
1967 Up CHEVROLET 8 ROUGH IDLE, PERFORMANCE USAGE, GOOD UPPER RPM HP, BRACKET RACING, AUTO TRANS W/ 3000+ CONVERTER, 4200-4600 CRUISE RPM, 11.5 TO 12.5 COMPRESSION RATIO ADVISED. BASIC RPM 4200-7200
Engine Size Configuration
396-454 C.I. V
Valve Setting: Intake .026 Exhaust .026 HOT
Lift: Intake @Cam 3412 @Valve 580 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 3528 @Valve 600
Rocker Arm Ratio 1.70
Cam Timing: TAPPET @.022
Lift: Opens Closes ADV Duration
Intake 39.0 BTDC 71.0 ABDC 290 °
Exhaust 84.0 BBDC 36.0 ATDC 300 °
Spring Requirements: Triple Dual Outer Inner
Part Number 99896
Loads Closed 150 LBS @ 1.900 or 1 29/32
Open 428 LBS @ 1.350
Recommended RPM range with matching components
Minimum RPM 4000
Maximum RPM 7500
Valve Float 8100
Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 23.0 BTDC 53.0 ABDC 105 256 °
Exhaust 68.0 BBDC 18.0 ATDC 115 266 °
Anyway there's a couple of ideas of where I'd be looking at. They are both solid flat tappets. I'd use the lifters with the EDM hole to lube better and then go through all the initial steps to break it in properly.
JIM
Melting Slicks
Joined: Jun 2001
Posts: 2,266
Likes: 549
UDHarold=HP, I'm running one of his lunati grinds 402a3lun 243in-251ex@.050. 1.8 in rocker 1.7 ex rocker. Using Howards edm solid lifters with it. Compared against a similar cam, dropped 5 tenths in the 1/8 with no other changes. Ron B.
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