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Tribal Scout

7 Posts

Posted - 14 Aug 2013 :  2:27:04 PM  Show Profile  Reply with Quote
Which Doug's Round Port Header

I'm ready to pull the trigger on a set of Doug's for my 68 GTO. It's a 4spd car that will have a full roller 455 stroker with E-heads @ 290cfm. What size primaries? Doug's offers both 1 7/8" and 2". Which one will be a better/easier fit? The D522s 2" don't list near the restrictions of the D567s. I've used the search but have been unable to find anyone with the D522s.

D522 2" 3 1/2 D567 1 7/8" w/ 3 1/2


Crazy Horse

851 Posts

Posted - 14 Aug 2013 :  11:54:02 PM  Show Profile  Reply with Quote
Hey Goatman,

I have a 69 GTO with a Round Port 455. Built up similar to yours, iron round ports flowing around 250 cfm intake. I have the 1 7/8 primaries and they fit pretty nice. The tightest spot was down on the frame next to the distribution valve on for the breaks. I did have to modify the lever on my clutch z-bar. I can send you some pics on how I did that. Overall, you may gain a few more ponies with the 2" primaries, but may lose a little of torque on the low end for street driving (but I think you have plenty to spare).

Doug's fit great. I think either choice you'll do well with. Are you planning to race a lot?

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