I love the recent post on BB headers. Great to see people mix it up. All questions should be answered at the track I guess. Anyway, the argument seemed to be settle on (depending on who you ask) motors under a certain size working well with 1 3/4", bigger or more enthusiastic motors 1 7/8" and big guns 2" or better. I seem to be somewhere between categories with a 625 horse street driven 482 BB in a '66 (4.10 rear with an M-22 4spd). Do I fall into the 1 7/8 category? I want it to redline around 6500, and have as much torque in the low and mid range as possible. I want the smallest headers, due to obvious fitment problems, but I don't want to give up TQ/HP. I understand that Hedman's fit best for these cars, but they don't offer a 1 7/8. They jump from 1 3/4 to 2", so these might be my choices. I hope that the previous post on this topic hasn't worn you guys out, as I would really appreciate some input on this decision. BTW, since my bottom end will hold around 850 HP, this motor might see some NO2 in the future, just to complicate things. Thanks, Kirk.

kboorman,

I'm in your approx situation.
505 cid, about 480-500 honest HP with accessories, etc.. according to EA 3.0, solid roller, etc..

If I had my choice i would buy a set of 1 7/8", and they are available from Sanderson for $335 uncoated or Hooker about the same..

Too much IMO for an uncoated header.
I bought 1 3/4" Hedman Elites with the 3/8" flange, 14 ga tubing.

IMO a set of 1 7/8" with a scavenger collector would be optimal on my combo and likely yours too.

However for my intents I went smaller rather than bigger...

But with N2O in the future you may opt the other direction...

I have a similar combo. With your HP and future of running NOS def. go with 2" and I recommend Hooker Super Comp. for quality and fitment! 1-3/4in headers are run on moderately built SBC and BBC heads flow way better so LOL there should be no problem with 2" for your healthy 625hp BBC which is approx. what I have on my 73'drag Camaro! Cheers dudes! :D

I hope everyone discussing the header primary size issue here and on the old post is/was relating this with open exhaust not a full exhaust system. With a full exhaust and variety of mufflers available this would change the performance results obtained. For example if you ran the 2 inch primary headers with a poor flowing muffler and tailpipes you may actually lose power than if the 1 3/4 primaries were used.

I would not use 1.75" pipes in your case, esp with a shot of NO2. IF you end up with 2" primaries, put an X pipe on. You'll gain back some of the bottom end.

Thanks for your input guys. I think that I'll go with the 2" with an x-pipe and hope they go in easy. I am using heads with raiesd exhaust ports (0.60"), which is something I probably should have mentioned in my first post, so I hope that doesn't complicate things too much. I have had a few people with 66's tell me that they had less problems with Hedmans, so I'm probably going in that direction. Besides, they're so much cheaper than Hookers that I can buy them uncoated, make whatever clearance adjustments are necessary and send them to Jet-Hot to be coated for less than a set of coated S/C's. Thanks again, Kirk

I too am in the same spot, 505", dynoed at 593hp @ 5400 rpms, 646ft/lbs@ 4200 rpms, daily driven, went with hooker competition 2" primaries, 3 1/2" collector with an h-pipe (and 40 series flows). Theres always the possibility for more hp/tq later, plus im at 600+ ft/lbs from like 2900 up or something like that so low end is plentiful for me.

what do you think about my headers 2 1/8 super comps with 3.5 collector and the new engine a 540 +8-71,twin dominators,dynoed 942/7500 and 820/4500.i feel like i could use bigger ,like,2 1/4 headers.the cam is a mellow roller with 0.636 lift and 262 at 0.050 intake 270 exhaust.