These are the specs i've decided on so far:

-Pontiac 400 block bored .030 over
-10:1 comperssion with forged pistons
-Edelbrock Performer RPM intake
-750 cfm carb
-Ported Heads (2.11/1.70)
-Roller rockers....maybe 1.65:1, not sure
-2,600-3,200 stall convertor
-TH350 Tranny

Ok, so for those specs I think I've narrowed it down to 2 hydraulic cams so far....here are the specs on them:

XE274H

274/286
230/236
.488/.491

XE284H

284/296
240/246
.507/.510

So what do you guys think......I want this engine to be built for high performance street, not conserned about MPG so much, just don't want anything crazy bad, nothin like 10 mpg highway. All I'm lookin for is enough low end to get me around the streets rather well, and enough vac for the power brakes.

Now the power band on the XE274 is from 1800-6000, while the XE284 is higher at 2300-6500...also comp cams requires a 2800+ stall speed convertor. The one I have for my TH350 is rated at 2,600-3,200 RPM so I think I'll be ok with that is I went with the XE284. But my gut is tellin me that that power band on the XE284 is a bit high for street drivin, so part of me is sayin go with the XE274 and another part wants the bigger cam. My main concern is that I don't "over cam".

I'm lookin for over 400hp on this motor, do you think the XE274 can produce that with my suggested mods? Or should I lean toward the XE284 for all out performane on the street.

Thanks for the help....it's all appreciated

 

I had a XE274 in a 400 (Chevy)... it's plenty. It's on the edge of too little vacuum for power brakes. Pontiacs don't react the same as SBCs to big cams anyway, I think you'll be plenty happy with that one. Watch out for the valve spring issues if you run the high ratio rockers.

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"So many Mustangs, so little time..."
ICON Motorsports

 

When in doubt, choose the smaller cam.

I think it will work better on your application anyway.