71-73 Swag

  • New T-Shirt Design (Also coffee mugs and posters!) – read more!
  • Mach 1 Key Tags available (almost gone!) – read more
  • Convertible Key Tags available (limited supply) – read more
  • Coupe Key Tags available (only a few left) – read more

  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Most aggressive idle cam recommendation for stock CJ heads
#1
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

Thanks!
Wade
1972 Mach 1 351 cj 4speed
"We confide in our strength, without boasting of it; we respect that of others, without fearing it."--Thomas Jefferson

  Reply
#2
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.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
  Reply
#3
(11-22-2017, 10:33 AM)scgamecock Wrote: 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-s...=1477&sb=2

73 conv. 460, D0VE large valve heads, Performer RPM manifold, Voodoo 227/233 cam, Holley 950 HP carb, C6 trans, 3.25 trak-loc.
  Reply
#4
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. 
  Reply
#5
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

Thanks!
Wade
1972 Mach 1 351 cj 4speed
"We confide in our strength, without boasting of it; we respect that of others, without fearing it."--Thomas Jefferson

  Reply
#6
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.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
  Reply
#7
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.
  Reply
#8
+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.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
  Reply
#9
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?

Thanks!
Wade
1972 Mach 1 351 cj 4speed
"We confide in our strength, without boasting of it; we respect that of others, without fearing it."--Thomas Jefferson

  Reply
#10
(11-23-2017, 06:13 PM)scgamecock Wrote: 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.

73 conv. 460, D0VE large valve heads, Performer RPM manifold, Voodoo 227/233 cam, Holley 950 HP carb, C6 trans, 3.25 trak-loc.
  Reply
Share Thread:  


Possibly Related Threads...
Thread Author Replies Views Last Post
  New camshaft time! 377 in Cleveland with CHI 2V heads. Bentworker 10 210 11 hours ago
Last Post: Bentworker
  Manual Valve Body with Stock Shifter cobra3073 11 334 03-28-2018, 04:11 PM
Last Post: 1973machi
  Trickflow heads on 351c with flat pistons Robsweden 20 1,574 02-20-2018, 01:48 PM
Last Post: Robsweden
  400M heads on 351C Odmark 2 686 01-17-2018, 09:34 AM
Last Post: Ron Tanzi
  Scott Cook Aluminum 4V Heads rotorr22 5 507 01-07-2018, 05:41 PM
Last Post: rotorr22
  what heads to use and why boilermaster 20 1,042 01-01-2018, 10:06 PM
Last Post: OzCoupe72
  Alternator for a 1971 351 C. I believe the 55 amp is stock. Pastorpat 9 574 11-27-2017, 12:48 PM
Last Post: Pastorpat
  Best heads for 302 RadRacer203 23 1,416 11-15-2017, 04:04 PM
Last Post: jowens1126



Users browsing this thread: 1 Guest(s)