What cam for a 500 EFI
 

Wanting to up grade for more power . I figure Crane Cams has the most experience with these motors. What have yall been putting in them?

Also will be changing the Tappets .They claim there hyd roller tappets say for the street. The street ones are usually on the heavy side.The 502 block takes a different style and they said something about different push rod lenth??

I am use to using the Crower stuff its more expensive but I have had good luck with them and we are WD with them.

What are yall running??


Thanks for your help


Rob

Re: What cam for a 500 EFI
 

Are you going to do the heads while you are at it?

Re: What cam for a 500 EFI
 

or replace them . waiting to see the condition of whats in side . Plan on inconle valves, new springs, tit retainers, etc.the heads where suppose to be ported . i have a buddy that has a 601 flow bench so we will see how the port job was :eek: i have ported a few big blocks castings before and had some fare # out of the ,but now days grinding on cast iron it might be easer to but the aluminum heads ready to go. just worried about the raised exhaust port with the headers alignment and clearance.



Cams???

Re: What cam for a 500 EFI
 

Strip,
When you have airflow the cam is black and white. Based on the air going in and coming out the camshaft can be designed to optimize the combination. Better the head flows the less cam is needed to make power at a given rpm range.

Tappets, the Morel stuff is top notch. These guys have been making roller lifters behind the scenes since the 80's. Their new retro hyd roller is a very nice piece. The design will fit either the early short lifter bores or the later taller ones. Lifters are designed to take the OEM hyd roller pushrod length.

Chris

Re: What cam for a 500 EFI
 

Crane 731 or 741

Re: What cam for a 500 EFI
 

Ok I looked in the merc Emanuel.

lift .342 at 1.7 rocker ratio I come up with 581 lift on both
the kicker is they say +or- .020 does this mean they do not know what the lift is???

Duration at .050 ex 227 ex 211 this seams pretty low but its a factory cam,right?


I called Crane today the Teck guy ask why I wanted to replace the cam that the factory cam was one of theres with a GM part # stamped on it. That I would NOT improve on it with a blower type installation.. If I went just NA it might improve.He said the factory cam was a good one and no need to change it and the specks on the factory cam was a dur at .050 230-235 and lift at 598 -610 and lobe at 114..thats diff than the BOOK??

So I said if I just wanted to throw away money just to say I put a cam in it WHAT?

He said the 168741 which is 236-244 lift 610-632 cut at 112. overlap still good for reversion ,water :eek:

Now this cam #'s is real close to a Crower I put in a another Blower motor I built that made 762hp on pump gas . 460ci 8-71 1to1 on boost,carbed.did not idle to well.I know the #'s on cams can be the same on one & makes more power [ramp profile] At these mild cam #'s I dont think I will be beating the tappets to death on a steep ramp profile.


I am getting the same info on the heads not to change them that they flow good to start with.

so the differance between just bolting a blower on and building a all aftermarket all out motor is the same horse power??


Help :D

Rob

Re: What cam for a 500 EFI
 

The Merc manuel for the cam in the 500EFI is wrong. I was told there was a "revision notice" out there for it.

The cam you listed are the right specs.

If I go forced induction on my 500's I plan to just "rering" the motor so I know exactly where the gaps are. Already did valve springs and cleaned up seats earlier this yr. I've always heard the 741 cam is an excellent cam in 500's with blowers, but I'm not sure I'll make a change there. You won't have any problems with lifters with either of those cams. I know people running hydralic rollers in the 252/262 @.050 area with .650" lift buzzing the sh@t out of the motors (6500) with no problems.

One way to pick up some power is to go to 509's" as it helps "unshroud" the valves.

The biggest power killer with the 500EFI's is the restrictive intake manifold. I've done a lot of research and been told you can spend tons on heads, cams, reprogramed ECU's etc, but you can't really get around the intake manifold problem without going down another road.

Re: What cam for a 500 EFI
 

jdnca1,

can you point me to any web sites or people to talk to about the intake on the 500EFI? I can not find any info on this
Thanks

Re: What cam for a 500 EFI
 

I have heard the intake plays out above 6000rpm. Some people told me to extrude hone the intake . Has any body done this ??

From the specks the stock and the 741 there not much difference.

My motors are suppose to be 509 already . I figure a re ring also. probably the Z gap rings .rebalanced assembly,bearings , already ordered the Moroso oil pumps. the norm bottom end stuff.

I am going to get the motors dynoed ,so I will let them do the ECM's then. :D

Re: What cam for a 500 EFI
 

I would call Cam Motion in Baton Rouge,La 225-926-6110.Real good guys have used them in my Drag race stuff for years.