Huge a** Cams?

[98blackmagic]

I have a new motor going in my 98GT (I've posted before about it) and I just found out what cams is on it, Comp XE278's Does anyone have these cams? And anybody have them on a automatic? The motor is built complete bottom end pistons, bearings, rods, Ported PI heads, 30lb injectors, ect.... I am just concerned on how the cams will work with my auto. I already have a custom tuned chip that I know I will have to have re-tuned after the install. Any info is a great help.

 

[back_in_black]

you have a 2,800 stall converter, I would think you would be OK

 

[98blackmagic]

From what I've read it calls for at least a 2400 so yea with my 2800 I feel pretty good, but I am concerned about something I read, cant remember where (Stangnet, ModularDepot, or ModularPowerhouse) it said something about the duration on a certain cam hurting performance because of the automatic

 

[mogs01gt]

what compression are you running?

 

[98blackmagic]

The pistons are new but there are no markings so I don't know how much comp. How can I find out how much I have?

 

[mogs01gt]

The pistons are new but there are no markings so I don't know how much comp. How can I find out how much I have?

The issue with those cames is the duration. If you run too much duration on the stock dished pistons, you may have piston to valve clearance issues. Meaning, your valves will stay open to long and could possibly smash into the piston. If you raised the compression by going with a less dished piston, you will need valve relief's put into the pistons.

well what kind did you buy? It will say on the box or the engine builder will know. Only way to find out is to do a compression test.

 

[98blackmagic]

I didn't buy the pistons they were already in the motor, (the motor came out of a car that my speed-shop owner bought and it had just been built by the previous owner but we cant get in touch with that person so we dont know the details on the pistons) I do know they are dished but other than that I don't know. A comp test would be the only way I guess. Any other issues with these big dam cams?

 

[mogs01gt]

NVM its an auto. Im not too sure of anything else. Im not too knowledged on bigger cams and autos.

 

[Dark Knight GT]

I hear some people have idle issues before a tune. That, and some people complain they cause the motor to "lope" a bit much at idle. Other than that, most people are fine with them. As for the valve smacking issue, only a few people have had this problem. Don't they make a special spring relief kit to help with this problem ? If they do, you might want to look into it just in case.