crvtkilla

At what point should you step up to 1 3/4 inch headers? im trying to decide between 1 5/8 and 1 3/4 in. the motor is a 347 with 10 to 1 compression, ported twisted wedge heads, AFM N-61 cam, systemax upper and lower. its going in a steet car but will prolly see the strip some to. i know the 1 5/8 will be better for the bottom end but i will probably be shifting at like 6300 or 6400 rpms and i dont want to choke it up high. thanks in advance for any advice.

w8less

the 1 5/8should will be fine

crvtkilla

yea thats kinda what i was thinking to. i just didnt want to go through with that and find out i should have went bigger.

5spd GT

Look into the 1.750" headers for sure. This is not a 302.

WhiteWindsor

My engine's only a few more cubes than yours and i have 1 3/4 long tubes.

mjr46

I'm running 1 5/8 lt's on my 347 with good results

nitrous_bob

not so much the cubes.. are you over 500 hp ? i will say i doubt it and agree 1 5/8"

WhiteWindsor

I agree it has nothing to do with the cubes. My set up is probably a little wilder than his. I was just stating what i have and if he ever does decide to go a little more radical the 1 3/4 will be there for him. But i know how that goe's, people make huge plans without keeping the cost in mind and usually dont do what they say they will.

crvtkilla

nah im not going to be near 500 any time soon. but maybe one day. evertime i put one together i want more. i havnt fired it up yet but im hoping for some where around 425 at the crank. im going to fire it up in a month or two and get it dynoed and all. i dont mind shelling out a little more cash for the 1.75 i just dont want it to be over kill and hurt me now. So i guess thats the question. will it hurt me now?

5spd GT

The top cam grinders that I have contacted before would both suggest 1.75" or larger.

Just something to think about...