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Original Message
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| Blue Thunder/FPP intake – Plenum notch and exhaust |
| By Robert - 05/21/2004 10:13:22 AM; IP 65.6.135.169 |
Blue Thunder/FPP intake – Plenum notch and exhaust crossover.
My engine plan is this:
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Engine is going in a 1972 F-100 Long Bed.
Use is home depot runs, around town errands, and probably occasionally dragging a ski boat to the lake.
Truck has a C6 built with a full TCI kit and a TCI Saturday night special converter.
Rear end is a 9” and will be having its gears and center changed to a true trak with between 3.70 and 4.11 depending on how the new engine runs (I am presently thinking 3.90)
It already has Hooker Competition headers, a Hooker Competition dual exhaust, with Dyno Max ultra flows. It is a 2.25 mandrel bent system, and is Jet Hot coated inside and out form the exhaust port to tailpipe exit.
The Truck also has a Crane 343801 cam, lifters, springs, retainers, locks and rocker arms. The cam specs are: ADV Duration: 278 °/ 290 °, 222 °/ 234 ° @.050 and .548 / 580 lift on 112.
I like the way this cam runs, not withstanding the fact it is in a worn out 360 with dismal compression even when new. I think the wide split in the pattern makes up a bit for the exhaust being on the smallish side.
I have an “S” code intake on it with a 3310 upgraded to a 428CJ look alike.
I’m planning to have the CJ sized valves installed in the stock heads C8AE-H and to put the 390 crank and rods in with Speed Pro forged .30 over flat tops, AFTER equalizing the chambers I figure they will be in the 9.75:1 range. It will be balanced and the cam straight up with an Edelbrock chain.
My hope is that it will be equal or slightly better than a Factory 390 GT @ about 335 HP; I really do not have a good reason for wanting that, other than it seems to be a reasonable benchmark.
Do you guys think it will turn that kind of power, and if not, where are the holes in my theory?
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Consensus seemed to be the biggest weak link in the engine was the factory “S” manifold, so I located and purchased a used FPP - Blue Thunder manifold. This manifold has a plenum notch and an exhaust crossover. This manifold was discussed here:
http://www.network54.com/Forum/thread?forumid=74182&messageid=1083714438
I know that the notch helps make power up top, and my can stops making power in the low to mid 5000 range, my question is will it hurt the low end enough to warrant my trying to some how un-notch it? My thought was that I could fabricate a sheet metal “U” to block it, or make a small block to bolt in (I’d be worried about that coming loose though) I’d prefer not to weld it up, because I may at some point go to a hotter cam.
My other question is should I block off the exhaust crossover (if for no other reason that to prevent paint burning off.) and if so what is the proper method. (Victor makes a gasket?)
Thanks in advance.
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This thread, so far...
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