I like the Hooker super comp but what size primarys should you run and ceramic or not?
Thanks,
Mike

what engine? combo? we need ALL the info!

DUH!!! sorry I forgot. 350 chev, 10.-1 pistons (stock 300 horse) 280H Comp Cams, 770 Holley street avenger, and Edelbrock Aluminum RPM heads, and a Edelbrock Performer intake. Its all mated to a 700R4 built by Bow Tie overdrives with a 3.73 posi
Thanks,
Mike

1-5/8" primaries, dont buy the coated headers, becuase they do a cheapie job and skip the inside (from what i've heard). I'd personally just paint them with VHT or homedepot barbicue black.

Try this calculator: http://www.headerdesign.com/

You need to register, then you can use the calculator. Be honest about your car and what you are using it for.
For my 406 it comes back with 1-5/8" x 39" primaries with a 2-1/2" collector. I had a set of 1-5/8" x 28" primaries with a 2-1/2" collector on my 67, so I am extending the primaries 11" for the new car.

------------------
1967 Nova coupe daily driver
406, 10:1, 224° cam, Q-jet, 700R4, 3465# w/driver
11.75 @ 117 thru the mufflers
18 mpg on the road

Nova,
are you going to use flowmaster scavenger collectors as extensions, or are you going to fab your own extension?

I've always wondered that if you bolt up an exhaust pipe to the end of the collector and its the same size as the collector, does it act as an extension to the collector?

It suggested 1-5/8"x 33" primaries with a 2.5" dia collector 13-1/2" long. Seems like a good program, thanks for the link Nova.

I selected #5 on the performance Factor, BIG Mid-range power with good top end.

Personally i going to use Dynomax 1-5/8" headers with flowmaster scavenger collectors that extend the primaries but will go into a 2-1/2" pipe instead of a 3" collector like most.

Hehehe...
I punched in my motor, and it shot up an error message: "Warning: Horsepower figure unrealistically low!"

CNC, Yes, if you have a 3-inch collector and 3-inch exhaust pipe, it is like extending the collector. Avoid a collector that is too large or you will slow the exhaust gas velocity down. Also, the cheap cone adapters everyone sells to hook the exhaust pipe to the headers aren't any good from a performance standpoint - the transition from one diameter to the other is too quick. The transition should take 6 to 12 inches. Several vendors sell parts to make a correct adapter.