331 Cam Combo Suggestions/opinions

[revhead347]

I had a TF3 in my last engine. It peaked at 5600 rpms. I don't have much faith in used cams either. I always considered them to be pretty much worthless. When I took it out, there didn't appear to be anything wrong with it, and still didn't feel right asking money for it. I traded it for a 12 pack of Fat Tire.

Kurt

 

[fiveohlover]

Ya i know my gt 40 lower isnt that great, but doesnt that upper box help with the upper rpm? I read that they are made for all top end, isn't that what the biger cams are made fro also?

 

[A5literMan]

Ya i know my gt 40 lower isnt that great, but doesnt that upper box help with the upper rpm? I read that they are made for all top end, isn't that what the biger cams are made fro also?

Yes the upper will like higher rpms but that lower is still a choke point. You are going to be hard pressed to make power above 6k rpms. You can make good mid to upper rpm power with your setup. Just not going to pull to 65-7k productively. Also the maf/tb combo is too small IMO for max power/breathing/rpm capability. If it's just a street car with the occasional strip pass I'd concentrate on mid rpm range with good throttle response and not worry about high rpm rips. And stock blocks don't like 65-7k rpms anyway.

 

[fiveohlover]

ya i will have to do some upgrading some day

 

[Gearbanger 101]

was that on a stock ECU and stock tach? If so, you werent really revving to 6700. Ive seen stock tach's off 500-800 rpms when they got to the dyno.

Agreed. Can't remember for certain with regards to the SN95 ECU, but the A9L in the Fox body ends the party at about 6,250RPM unless you have the rev limter tuned out of it.

I've got the same XE274HR in my 331, less robust heads, but a much better intake and although it'll pull all the way to the limiter, I'm certain it would sign of long before 6,800RPM.

Personally, I'd be less concerned about the cam selection on this one and abandon the idea of using that GT40 intake. It'll be torquey, but it's gonna cork your horsepower figures like there's no tomorrow!

 

[fiveohlover]

Agreed. Can't remember for certain with regards to the SN95 ECU, but the A9L in the Fox body ends the party at about 6,250RPM unless you have the rev limter tuned out of it.

I've got the same XE274HR in my 331, less robust heads, but a much better intake and although it'll pull all the way to the limiter, I'm certain it would sign of long before 6,800RPM.

Personally, I'd be less concerned about the cam selection on this one and abandon the idea of using that GT40 intake. It'll be torquey, but it's gonna cork your horsepower figures like there's no tomorrow!

good info, but ya i have a msd 6al on my car now, so where does your car make most of its power at with the xe 274hr?

 

[90lxcoupe]

The 6al wont make the car rev any further. The factory ECU cant keep up and slows way down past 6000rpms. Even with the factory limiter removed, the A9l will limit RPMs. Some guys have done cristal mods to the ECU, but that is hit or miss from what i have read.

 

[tannerc91gt]

Custom. It's damn near the same cost. No excuse there really. But if it were me and I was spending some coin on a short block I'd be willing to take my time to save and put a solid valvetrain together for it. That intakes really not gonna cut it either way

 

[Gearbanger 101]

good info, but ya i have a msd 6al on my car now, so where does your car make most of its power at with the xe 274hr?

The 6AL's only really nice feature is the soft touch REV limiter IMO. Otherwise I don't have much use for them. The stock ignition works pretty well. The problem with using the 6AL, to set your REV limit is that they only cut spark.....not the fuel like the stock ECU does. Cutting spark is a good thing, but when the ECU says sorry....no more fuel for you at the factory set 6,250RPM range, the party is over, regardless where you've got the MSD set.

With the XE274HR in there, the engine is a little softer than stock down low, but really comes on above 3,000RPM and carries on with a nice steady pull all the way though to red line. Where the stock cam starts to fall off shortly after about 5,400RPM, the 274 seems to just keep pedalling. How your cam performs will be largely dependant on your supporting components. In you case, the GT40 lower you have is going to put an end to the power band long before your cam will.

If you're dead set on sticking with that GT40, then go with a cam that takes advantage of your power curve at a lower RPM and works best below the 6,000RPM range. You'll have a much nicer and most likely faster car for it.

 

[fiveohlover]

Hey thanks for the good info guys