Can anyone suggest what size primaries to get on my car. 1979 Trans Am with a 400,5-speed. I rated at 260 RWHP, and 332 RWTQ. I was going to go Hooker competition with 5/8. Should I go bigger primaries?

 

5/8" will be fine for that combination. 3/4" should be used once you start getting close to 500 hp or start buzzing the engine over 6500 rpm.

When I used a 383 and ran high 11's at 117 mph I was only using 5/8" primaries.

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87 IROC SuperPro race car
461 big block
Best ET on a time slip: 11.589
Best MPH on a time slip: 115.91
Best corrected ET: 11.114

Altitude corrected rear wheel HP: 457
Best 60 foot: 1.646
Member of the Calgary Drag Racing Association

[This message has been edited by Stephen 87 IROC (edited June 27, 2002).]

 

If your going to use any power adders then i would use the 3/4's

 

I second the 1 5/8 vote. even w/power adders at that power level he prolly wont need the bigger ones. you'll have more torque down low w/the smaller headers than you would gain HP in the upper ranges. IMHO anyways. chris

 

The increased HP in the upper range would never be seen in a street driven vehicle. The rpm range of a daily driver will see more improvement with the 1 5/8".