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well just read the title. trickflow heads that have d-ports do i need d-port headers? if not how do hedman 68470 headers sound? i am shooting for true dual 2.5 exhaust. not daily driven so ground clearance isnt a big deal. check sig for mods
__________________ 91 camaro: 350 4 bolt,luinati cam 218 dur. 458 lift both sides 110lsa, trick flow 195cc heads 62 cc chambers 2.02, 1.6 valves, Edelbrock Performer RPM Intake 600cfm holley 1850 vac secondary hedman longtubes, built 700r4 , 3.73 posi, k&n 14x3 filter, weld draglite wheels (15x3.5 with mickey thompson's and 15x8 with cheap tires) 1/8TH MILE BEST TIME-9.069 AT 76MPH BEST MPH-9.2XX AT 78MPH
Re: i have d-port heads, do i need d-port headers???
im in the same boat as u. i have dual 3" with xpipe and im throwing in a 383 with patriot 195cc heads.. but they have square ports... and my headman longtubes have round ports.... so i think i would have to go round port gaskets but that would cause a nice little exhaust restriction
__________________ In the process:
521cuin Big block ford
Ford C-6 trans
Ford 8.8 w/3.55gears, custom shorty Tq arm
Re: i have d-port heads, do i need d-port headers???
i guess the question is how much of a restriction would it be...
for square port heads, i think that as long as the cross section area of the headers was slightly larger than that of the heads, you would be ok, but for D port heads, i would try and find D port headers.
no real concrete theories here, just my intuitive hunch...
Re: i have d-port heads, do i need d-port headers???
Quote:
Originally Posted by customblackbird
heads are square port 1.375x1.4375" and the headers i have a round port stock headman longtubes.... 1 5/8"
stock round port i think is either 1.38" dia or 1.59" dia...
ok, so multiply 1.375 x 1.4375 to get cross section of heads
As for the headers, take 1 5/8 x 1 5/8 x 3.14159 to get cross section of headers.
Thee does not account for wall thickness though. If possible, measure the INNER diameter of the headers to do your math. As long as the headers number is bigger, you are ok
Re: i have d-port heads, do i need d-port headers???
91 camaro racer... i would say u would need dport headers... they are alot different from just square port/round port headers... u can get away with square port/round port headers on square/round port heads. but D ports would require dport headers... another reason i stayed away from them.
red_dragon_84, i did the math...
1.375x1.4375= 1.9765 cross section of the heads
1 5/8=1.625
gauge of the headers is 18gauge which is equal to about .125-1.625=1.5" inner dia, so the Radius is 0.75 so Rsquared is 0.5625
plug this into Pie(3.14159)xRsquared
3.14159x0.5625= 1.767 cross sectional area of the round port header, vs the 1.976 cross section are of the head... so my head ports are still larger by 0.209"
Re: i have d-port heads, do i need d-port headers???
As long as the opening of the header completely encloses the opening of the exhaust port, you're fine. I used both SLP 1 5/8" and Dyno Don's 1 3/4" headers when I had the Corvette L98 d-port heads. The SLP's just barely fit, but Don's headers were (and still are) excellent.
Re: i have d-port heads, do i need d-port headers???
Quote:
Originally Posted by customblackbird
red_dragon_84, i did the math...
1.375x1.4375= 1.9765 cross section of the heads
1 5/8=1.625
gauge of the headers is 18gauge which is equal to about .125-1.625=1.5" inner dia, so the Radius is 0.75 so Rsquared is 0.5625
plug this into Pie(3.14159)xRsquared
3.14159x0.5625= 1.767 cross sectional area of the round port header, vs the 1.976 cross section are of the head... so my head ports are still larger by 0.209"
well it will be a restriction, but not too much.
ideally your headers would be slightly larger than the heads.
its your decision i guess.
p.s. i love it when i explain math to people...
tires and final drive ratios are fun...
also, its red_dragon_85, not 84 lol.
after all, they didnt make IROCs in 84 now did they...
jk
im just messin with ya
Re: i have d-port heads, do i need d-port headers???
Quote:
Originally Posted by RED_DRAGON_85
ok, so multiply 1.375 x 1.4375 to get cross section of heads
As for the headers, take 1 5/8 x 1 5/8 x 3.14159 to get cross section of headers.
Thee does not account for wall thickness though. If possible, measure the INNER diameter of the headers to do your math. As long as the headers number is bigger, you are ok
lol sry RED_DRAGON_85!!! that was my fault... and i love it when ppl EXPLAIN THE CORRECT MATH EQUATIONS when posting them... i did your math and my cross sectional area for a 1 5/8" header came out to 7.669 lol thats a HUGE BlTCH!!!!! lol
its not DIAmeter X diameter x 3.14159 for area of a circle... its PIEr^2 which is radius X radius x 3.14159
hahaha im just messin as well. thanks for the help tho... maybe i'll port the header openings to smooth out the trasition from the larger head exhaust openings to the smaller round exhaust header ports.... hmmmmm kinda like grind out a slight square and have it transition into a circle... not gona keep the heads for long.. .they need to be replaced in a yr or so.
91 camaro: 350 4 bolt,luinati cam 218 dur. 458 lift both sides 110lsa, trick flow 195cc heads 62 cc chambers 2.02, 1.6 valves, Edelbrock Performer RPM Intake 600cfm holley 1850 vac secondary hedman longtubes, built 700r4 , 3.73 posi, k&n 14x3 filter, weld draglite wheels (15x3.5 with mickey thompson's and 15x8 with cheap tires)
"It's not the tires squealing, it the asphault SCREAMING!!" 
