need cam advice

-
R

rcottick

Well-Known Member
Joined
May 27, 2004
Messages
86
Reaction score
0
Location
Sterling Heights, Mi
motor is a 73 340 rebuilt with 10.5-1 comp. trw .030 over slugs. heads are j heads 915's with 2.02's rocker arms are factory adustables so I will more than likely have to run a mechanical cam and solid lifter. Intake is an edelbrock performer and I will top it off with a 750 holley mech. secondaries. it will be running a 904 auto with 2200+ stall convertor 8 3/4 rear with soon to be 3.91's or 4.10's

I would like a lopey idle with great lower end response. Have been looking at the comp cam series What do ya'll think
 
You can punch your info in at CompCam site and they will send you a recommendation if you like. I think some of the other cam outfits may do this also. Mike
 
rcottick said:
I would like a lopey idle with great lower end response. Have been looking at the comp cam series What do ya'll think
Click to expand...

A lopey idle and great low end response are some what mutually exclusive. It's the inefficient filling of the cylinders caused by a lot of overlap that makes the lope and those are the same things that kill the low end power.

Comp is advertising a series of cams called "Thumper" that are supposed to give you the lope with out killing off all the bottom end. But, there is no free lunch so you will be giving up power else where in the power band.

The Comp XE284 cam will have a lope but also gives up a lot of low end power and requires a convertor with a higher than stock stall speed.
 
You do not have to run a mech. cam just because you have adjustable rockers. In 1970, that is just what MoPar did on the T/A engines. Hyd. cam and adjustable rockers. OE style pushrods can still be had from Comp Cams or other places.
 
but if I replace the pushrods I will have to replace the rockers as well right.
So my current pushrods and rockers will work ok with hydraulic lifters is what your saying?
 
The pushrods for hydraulic cams with adjustable rocker are a different length than the solid lifter pushrods.


Chuck
 
rcottick said:
but if I replace the pushrods I will have to replace the rockers as well right.
So my current pushrods and rockers will work ok with hydraulic lifters is what your saying?
Click to expand...

Wait, let me get this straight. You have "rocker arms are factory adustables " so right there and then, your goiong to need different pushrods than what came stock. Did you know that?

The pushrods you'll need have to have a cup up top for the adjuster of the arm. Right? You knew that?

The length of the pushrod varies from a Hyd. cam to a solid cam. Did you know that?

Figure out what your doing cam wise and then order the pushrods to length. You can get a pushrod length cheacker from various sources like comp or huges.
 
No you dont have to replace the rockers and pushrods as a set. Just get the correct length pushrod for hyd lifters and adj rockers. Crane comp etc sell them.
 
no, no, no, you guys have it all wrong. If you have adjustable rockers you must have adjustable lifters. Then you have to get the cam with adjustable lobes to make sure you get the duration dialed in correctly. Also you may want to invest in adjustable pushrods and adjustable valve covers for clearance issues.:toothy10::toothy10::toothy10::toothy10:
 
When it comes to off the shelf cams, beware!. Most cams ( I and know for sure Comp cams do this) "off the shelf" cams are ground around the most popular GM grinds and profiles. For example, the Comp Cams CS XE274H-10 for GM is the same grind as the CRS XE274H-10. This is ****!! The only difference is the blank billet they put in the machine. The cams are all ground around the small 0.840" lifter (Fords are approx. 0.866) bores. As you all know Chryslers are 0.904" which is much different. The lobe tapper on the cam is incorrect. All cams have to be checked for extra lobe tapper. My XE274 had three lifters that were not spinning. The most commond one is on No. 1 intake on these Chryslers. I found that the cam had only 2 thou tapper. All lifters were spinning extremely slow. Not good. I had to get the cam ground by a local guy to have 4 thou lobe tapper and also redressed to quiten the lifter noise produced by the agressive intake ramps. Now they spin very well almost 1/4 turn per lift and lifter noise is ALL gone. I did not like the XE range as the valve train was noisy. I will not use them again. Be aware of this problem. Check for lobe tapper on "off the shelf" cams.
Regards
Billy D...
 
You must log in or register to reply here.
-

Back
Top