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Cam Experts i have questions #1359379 12/26/12 03:40 PM 12/26/12 03:40 PM
Joined: Feb 2006 Posts: 501 CEDAR RAPIDS Plymouth340 OP mopar
Plymouth340 OP mopar Joined: Feb 2006 Posts: 501 CEDAR RAPIDS	i have a small block and would like to install a larger cam without having to take motor apart and cut pistons. How can i figure how big i can go as it is now....right now i have .090 piston to valve on intake and exhaust..the cam now has lift of 630 intake, 650 exhaust,duration @ .050 is 278 intake. 286 exhaust. lobe seperation is 106.rocker arm ratio is 1.5 7519269-DusterPicsandMore008.jpg (53 downloads)

Re: Cam Experts i have questions [Re: Plymouth340] #1359380 12/26/12 03:56 PM 12/26/12 03:56 PM
Joined: Nov 2010 Posts: 1,397 Carson City, Nevada Biginchmopar pro stock
Biginchmopar pro stock Joined: Nov 2010 Posts: 1,397 Carson City, Nevada	My first qustion is by saying you want to go bigger do you mean more lift? I did see the exhaust lift is higher than the intake. I usually see more duration with less lift on the exhaust side. I see room from improvment on the intake but not much on the exhaust.

Re: Cam Experts i have questions [Re: Biginchmopar] #1359381 12/26/12 04:03 PM 12/26/12 04:03 PM
Joined: Feb 2006 Posts: 501 CEDAR RAPIDS Plymouth340 OP mopar
Plymouth340 OP mopar Joined: Feb 2006 Posts: 501 CEDAR RAPIDS	yes more lift. i feel the cam is small for my combo. i did have a 630 lift intake and exhaust and installed this and car picked up a tenth in quarter..got w2 heads that flow about 315 cfm. motor is 398 ci

Re: Cam Experts i have questions [Re: Plymouth340] #1359382 12/26/12 04:11 PM 12/26/12 04:11 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: yes more lift. i feel the cam is small for my combo. i did have a 630 lift intake and exhaust and installed this and car picked up a tenth in quarter..got w2 heads that flow about 315 cfm. motor is 398 ci Your pretty close to max now if your numbers are real... you might get .010 more

Re: Cam Experts i have questions [Re: MR_P_BODY] #1359383 12/26/12 04:15 PM 12/26/12 04:15 PM
Joined: Feb 2006 Posts: 501 CEDAR RAPIDS Plymouth340 OP mopar
Plymouth340 OP mopar Joined: Feb 2006 Posts: 501 CEDAR RAPIDS	Quote: Quote: yes more lift. i feel the cam is small for my combo. i did have a 630 lift intake and exhaust and installed this and car picked up a tenth in quarter..got w2 heads that flow about 315 cfm. motor is 398 ci Your pretty close to max now if your numbers are real... you might get .010 more those numbers are what the cam card said, i havent checked actual lift at the retainer yet

Re: Cam Experts i have questions [Re: Plymouth340] #1359384 12/26/12 04:19 PM 12/26/12 04:19 PM
Joined: Jul 2004 Posts: 19,318 State of confusion T Thumperdart I Live Here
Thumperdart I Live Here T Joined: Jul 2004 Posts: 19,318 State of confusion	Quote: yes more lift. i feel the cam is small for my combo. i did have a 630 lift intake and exhaust and installed this and car picked up a tenth in quarter..got w2 heads that flow about 315 cfm. motor is 398 ci In addition to what others have said, what do the heads flow and where do they peak at? 72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....

Re: Cam Experts i have questions [Re: Plymouth340] #1359385 12/26/12 04:25 PM 12/26/12 04:25 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Quote: Quote: yes more lift. i feel the cam is small for my combo. i did have a 630 lift intake and exhaust and installed this and car picked up a tenth in quarter..got w2 heads that flow about 315 cfm. motor is 398 ci Your pretty close to max now if your numbers are real... you might get .010 more those numbers are what the cam card said, i havent checked actual lift at the retainer yet I would pull 4 sets of springs and use a set of light test springs (each corner) and check what you really have... till then your just guessing and no one can say for fact

Re: Cam Experts i have questions [Re: Thumperdart] #1359386 12/26/12 04:28 PM 12/26/12 04:28 PM
Joined: Feb 2006 Posts: 501 CEDAR RAPIDS Plymouth340 OP mopar
Plymouth340 OP mopar Joined: Feb 2006 Posts: 501 CEDAR RAPIDS	Quote: Quote: yes more lift. i feel the cam is small for my combo. i did have a 630 lift intake and exhaust and installed this and car picked up a tenth in quarter..got w2 heads that flow about 315 cfm. motor is 398 ci In addition to what others have said, what do the heads flow and where do they peak at? i dont have the flow numbers but hensly did a max port job and 2.08 intake valves and this motor pulls hard to 7500 and thats where i"m shifting at.

Re: Cam Experts i have questions [Re: Plymouth340] #1359387 12/26/12 04:34 PM 12/26/12 04:34 PM
Joined: Jan 2003 Posts: 31,060 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 31,060 Oregon	If it is a roller cam then you should be able to add more lift without any problem. On a flat tappet cam you might be getting close to the limit. Best way to know for sure is to pull the valve springs off of one cylinder and then map the valve to piston clearance over a range of 30 or 40 degrees of crank movement. Once you have that information you can talk to a cam grinder and tell them what you have. Then it is just a matter of figuring out how much area under the curve they can fit in there.

Re: Cam Experts i have questions [Re: Plymouth340] #1359388 12/26/12 04:36 PM 12/26/12 04:36 PM
Joined: May 2011 Posts: 4,489 northern,Ohio,USA C Clanton master
Clanton master C Joined: May 2011 Posts: 4,489 northern,Ohio,USA	If you get a custom cam I think they can have a faster,larger ramp/lift and close it where you are at. GOTBOOST!New improved with Victor heads. http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/

Re: Cam Experts i have questions [Re: MR_P_BODY] #1359389 12/26/12 04:48 PM 12/26/12 04:48 PM
Joined: Aug 2003 Posts: 11,179 Atco NJ DJVCuda I Live Here
DJVCuda I Live Here Joined: Aug 2003 Posts: 11,179 Atco NJ	Quote: Quote: Quote: Quote: yes more lift. i feel the cam is small for my combo. i did have a 630 lift intake and exhaust and installed this and car picked up a tenth in quarter..got w2 heads that flow about 315 cfm. motor is 398 ci Your pretty close to max now if your numbers are real... you might get .010 more those numbers are what the cam card said, i havent checked actual lift at the retainer yet I would pull 4 sets of springs and use a set of light test springs (each corner) and check what you really have... till then your just guessing and no one can say for fact If you are trying to cut it as close as possible - dont skimp and check one cylinder - check all 4 corners and make sure you have the room - unless you have a completely blueprinted engine now with the deck heights at all corners, etc - dont take that chance.

Re: Cam Experts i have questions [Re: Plymouth340] #1359390 12/26/12 06:18 PM 12/26/12 06:18 PM
Joined: Aug 2003 Posts: 43,259 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,259 Bend,OR USA	Have you check the ratio on your rocker arms yet, IE set the vave lash and then check the lift at the retainers, do the math from the cam card to determine if your rocker arms are really 1.5 ratio? If not you might want to try that, if there 1.5 or lower you might get what you want by buying and using a good set of 1.6 ratio rocker arms I have ad the motor loved it Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Cam Experts i have questions [Re: Plymouth340] #1359391 12/26/12 07:09 PM 12/26/12 07:09 PM
Joined: Jan 2003 Posts: 5,894 Florida Locomotion master
Locomotion master Joined: Jan 2003 Posts: 5,894 Florida	If you change anything with the cam or rockers, you really should re-check piston-to-valve clearance instead of taking anything for granted. Besides the obvious higher lift with higher ratio rockers or bigger cam lobes, duration, lobe seperation and where it's installed will affect the clearances as well.

Re: Cam Experts i have questions [Re: Locomotion] #1359392 12/26/12 07:18 PM 12/26/12 07:18 PM
Joined: Aug 2005 Posts: 761 Southington Ct. T turbobitt super stock
turbobitt super stock T Joined: Aug 2005 Posts: 761 Southington Ct.	There are so many variables I think its almost impossible to tell. For example - you can go with a faster ramp cam at the same rated duration and actually have more duration at .050 and .200 lift. This may get you in trouble with V to P clearance. Also can open lobe seperation to increase V to P. Advance and Retard is another factor. Allan G. 1970 Challenger w/572 Hemi street car and my pride and joy. 1986 T-Type with 272 Stage 2 Buick V6 engine - True 8 second street car. Just updated the engine and put down 928 HP @ 35# boost to the ground on chasis dyno. 1976 Cee Bee Avenger Jet Boat - 460 Ford powered.

Re: Cam Experts i have questions [Re: AndyF] #1359393 12/26/12 11:35 PM 12/26/12 11:35 PM
Joined: Feb 2006 Posts: 501 CEDAR RAPIDS Plymouth340 OP mopar
Plymouth340 OP mopar Joined: Feb 2006 Posts: 501 CEDAR RAPIDS	Quote: If it is a roller cam then you should be able to add more lift without any problem. On a flat tappet cam you might be getting close to the limit. Best way to know for sure is to pull the valve springs off of one cylinder and then map the valve to piston clearance over a range of 30 or 40 degrees of crank movement. Once you have that information you can talk to a cam grinder and tell them what you have. Then it is just a matter of figuring out how much area under the curve they can fit in there. yes solid roller

Re: Cam Experts i have questions [Re: Locomotion] #1359394 12/26/12 11:37 PM 12/26/12 11:37 PM
Joined: Feb 2006 Posts: 501 CEDAR RAPIDS Plymouth340 OP mopar
Plymouth340 OP mopar Joined: Feb 2006 Posts: 501 CEDAR RAPIDS	Quote: If you change anything with the cam or rockers, you really should re-check piston-to-valve clearance instead of taking anything for granted. Besides the obvious higher lift with higher ratio rockers or bigger cam lobes, duration, lobe seperation and where it's installed will affect the clearances as well. checking the piston to valve is a must..

Re: Cam Experts i have questions [Re: Plymouth340] #1359395 12/26/12 11:55 PM 12/26/12 11:55 PM
Joined: Jun 2012 Posts: 1,899 MYRTLE BEACH SOUTH CAROLINA E ek3 top fuel
ek3 top fuel E Joined: Jun 2012 Posts: 1,899 MYRTLE BEACH SOUTH CAROLINA	.090 is on the limit. you can close up the duration or change the overlap to increase the v-p clearance while adding 1:65 or 1:7 rockers. usually you can get a little extra lift but you are closing up the dur. to get it. por nada por nada.[you dont get somthing for nothing] give here take there. if you want more power , make room in those valve pockets for a 700" cam and and get more of everything! there is a phsyical limit at some point with the piston and cam combo..

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