captainstalin`

iTrader: (5)

another 1 3/4 vs 1 7/8 thread ;D. I've read all the old ones until my eyes have gone fuzzy and my brain turned to mush. is 383 stroked enough to warrant 1 7/8? na compression over 11 to 1 and almost an insignificant .010 overbore. tea stage 1.5 head and crane cam 224/232 115 lsa. id rather not lose anything down low to gain 5 peak hp.

Ironxcross

iTrader: (8)

get the 1 7/8

if you're going to make more power, you want more exhaust flow.

ChocoTaco369

What's your anticipated rwhp? What are your anticipated shift points? The point of 1 7/8 headers is they allow to rev higher up in the rpm range and make more power up there. You'll lose low end, so you need high shift points to make it worthwhile. If you're making 420rwhp with shift points of 6500 rpm's or less, I'd say don't waste your money. If you're making 460+rwhp with shift points of 7,000 rpm's, I'd say definitely go for it. If you don't have the high rpm power being lost through 1 3/4 headers, you'll lose by going 1 7/8. Know what I mean?

Give us a little more info on your setup along with your intentions for power. With that cam, I'd imagine you wouldn't be revving all that high. Perhaps a 1 3/4 stepped to 1 7/8 header would be the best for you.

twpetry

iTrader: (1)

there is your answer. you will definitely lose some low, how much you gain up top is To be determined. Maybe go with some stepped headers??

Arc00TA

iTrader: (17)

I would just go with the 1 7/8 if you want them (you obviously do otherwise you wouldn't ask us to justify it). People here seem to think an additional 1/8th inch is going to wipe out every bit of torque you had with 1 3/4, despite the fact that it has been proven that they both work about the same until you start getting into bigger cubes with a lot more flow over a 346 or FI, with the advantage going to the bigger primary there. Its not like you're asking about stepping up to 2 1/4 primary headers or something ridiculous.

luckyhenriksen

iTrader: (1)

I would just get the biggest and baddest you can afford

Magic Man

I think the formula is 10% over exhaust valve.So 1.57 would be about 1 3/4.

SS1875

iTrader: (34)

1 7/8 on my 383/M6 running 1.60 exhaust valves ...car made nearly 500 NA RWHP and 440RWTQ prior to my cam change last fall. I would do it and not look back...JMO.

john563

iTrader: (17)

I have TSP stage 2.5 5.3 heads ported 90/90 and a pat G 232/238 6xx 6xx 111+s cam on xfi lobes..Currently I have hedman 1 5/8 step to 1 3/4..I wanted to change headers and this firdya i'll receive my hooker 1 7/8th,so you know what gets my vote..It wiil hlp when cubes increase or if I decide to spray til I do it will help too..I wish I started with these So I would not have to be buying twice,but its up to you

02BLKWS6MD

iTrader: (22)

I'd definetly go with stepped headers.

MeangreenHD

iTrader: (6)

^^^^+1

jmilz28

iTrader: (13)

You will not lose torque with the 1 7/8. I have graphs of my car that show good numbers and a good curve, as good or better than many similarly modded bolt on cars.

If you will never ever do any more mods, stick with 1 3/4. Otherwise, 5hp/tq one way or the other is unnoticeable in these cars and the bigger tubes gives you room to grow. Most of the time, when people claim loss of torque it's because they didn't tune properly for the change.

More important is the header manufacturer in terms of design and quality. ARH or Kooks are the only options for my money, though I would consider the less expensive TSP 1 7/8 just out of Texas patriotism. Buy once, buy right.

captainstalin`

iTrader: (5)

-6cc mahle dome pistons. crane gold 1.7 rockers. 62cc chambers 218 intake runner and 80 exhaust runner. Ferrea 2.020 Intake Valve. REV 1.57 Exhaust Valves. y pipe is going to be catted if that helps any. probly going with fast 90/90 intake setup cus that weiand thing is beat. i dont have anything else planned for the near future..