Keep the 2.5 exhaust.You don't need 3" for this build.I will guess 400-425 hp and 500 tq with a fat torque curve.Watch the total timing as it may not need more than 35*.
I disagree with the headers being over rated statement.They would add 10-15 hp and 20 ft lbs IMO.
I think that's a fair assessment about headers. Hey, people install them for a reason. I like the look of factory manifolds and the low rise intake I'm using because of stock hood clearance concerns. I always like to leave a little to be had. If i like the way it runs in the car, I'll leave it. If i want more out of it I'll install headers, the edelbrock RPM intake, swap out the 3.23s for maybe 3.91s and call it a day I appreciate the responses. -Marc
Joined: Wed Nov 17 2010, 03:28PM
Location: florida
Posts: 1311
motor prob in the 400-425 hp range but ditch the stock ignition and step up to a capacitive discharge system and have the dist curved as mentioned and you will see a better reving engine and may sqeak a few more ponies than that a stock orange box.the speed demon carb could give you some tuning troubles so be aware.what about your fuel system? don't forget about it.stock mechanical will work but at full throttle is it really?good pickup,good supply lines etc,will make the difference
Joined: Mon Jan 16 2006, 02:52AM
Location: Vantaa,Finland
Posts: 379
Some years ago I built a mild stroker with magnum exhaust manifolds and compared them with 1 3/4" headers in the dyno, the rest of the exhaust and mufflers were the same with both combos. The result; the headers made about 5% better peak power and about 10% more low end torque. This was with a relatively small primaries for a 489. Similar results with a small block 416 using original E-body 340 manifolds and 1 5/8 primary headers. the difference in peak power was actually bigger in the small block.
I definitely believe headers would bring up the numbers. I may swap a set in sometime. The car is going to be a "clone" of an unmarked police cruiser. Maybe I'll run it at the strip, but mainly i want something to cruise in once in a while and go to local car shows with. Thanks for everyone's input!