Most aggressive idle cam recommendation for stock CJ heads

[scgamecock]

I have to change the water pump on my 72 351 CJ and want to put a cam in it while I'm at it.  The heads are stock and so are the pistons.  What is the choppiest cam I can run without:

• modifying the pedestal mounted rocker arms
  
• Having piston clearance issues
  
• changing springs
  

• I would like to go solid flat tappet as they usually perform better and have a much more radical sound.  I have a manual transmission and manual brakes so vacuum is not an issue.  The car is a cruiser not a racer but I want something with as aggressive idle as possible.
  

• I am also installing a single plane torque intake and 650 mechanical secondary Holley.  Would I need or want full roller or roller tip rockers?
  

• Please recommend lift\duration and specific cams with links to them. 
  

Thanks!

Wade

 

[Don C]

Solid lifters are not feasible with stock lifters, there is no way to accurately adjust valve clearances. The only two ways would be with different length push rods or pedestal shims, and neither one offers small enough size increments.

I believe the only way you'll be able to get a lumpy cam without changing valve springs is with a custom grind. Most off-the-shelf performance cams also have higher lift, which will cause your stock springs to bind.

Finally, a low compression engine will not respond well to an aggressive cam and a single plane manifold. Driveability will suffer on a street car.

 

[TommyK]

I have to change the water pump on my 72 351 CJ and want to put a cam in it while I'm at it.  The heads are stock and so are the pistons.  What is the choppiest cam I can run without:

• modifying the pedestal mounted rocker arms
  
• Having piston clearance issues
  
• changing springs
  

• I would like to go solid flat tappet as they usually perform better and have a much more radical sound.  I have a manual transmission and manual brakes so vacuum is not an issue.  The car is a cruiser not a racer but I want something with as aggressive idle as possible.
  

• I am also installing a single plane torque intake and 650 mechanical secondary Holley.  Would I need or want full roller or roller tip rockers?
  

• Please recommend lift\duration and specific cams with links to them. 
  

Thanks!

Wade

Comp Thumper

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1477&sb=2

 

[c9zx]

Mellings 24224. It is a copy of the Ford OTC cam D1ZZ-6250-BX. Easy on valve train. A lot depends on the condition of the 45 year old springs. 

 

[scgamecock]

I really should have thought About valve lash for a solid cam. That was pretty dumb on my part!

I should have also said recommended matching cam kit with springs and retainers.

Wade

 

[Don C]

No reason to feel dumb, just part of the learning process. If you stick with this forum for a while you'll be answering these questions.

 

[c9zx]

Picking springs is tricky not knowing what has been done to the heads and valves in the past. Has it had a valve job, seats replaced, valves replaced, retainers replaced, offset locks used to get proper spring height, etc. Installed spring height can vary significantly from one valve to the next depending on wear and the quality of any valve work done in the past. I know you want to do a "while I'm there I may as well as do...." upgrade. However, as you probably know these upgrades tend to expand into much larger projects. Good luck with whatever you decide to do.

 

[Don C]

+1 on that. I was going to install a roller cam, and now I'm at the point of possibly needing a block, got to get it to the machinist and see what he says.

 

[scgamecock]

I have a 460 on the stand but that will be a while before I can get all the parts and machine work done to build a stroker.

I have no idea what, if anything has been done to the heads in the past. Would that thumper cam be small enough not to worry about spring bind?

 

[TommyK]

I have a 460 on the stand but that will be a while before I can get all the parts and machine work done to build a stroker.

I have no idea what, if anything has been done to the heads in the past.  Would that thumper cam be small enough not to worry about spring bind?

Coil bind shouldn't be an issue. Valve float will be.