header flanges for ironhead, and other v6 header stuff

[sharkey]

im going to be building a set of headers for my car when i put my new motor in. im just trying to collect some info at the moment. im planning on building 1 3/8" primaries 32" long with a 10" long collector

first off, flanges: does anyone know who makes flanges for the ironhead that are less than 1.5"??? i found one company (headers by ed) but they want over $200usd for a pair of 1/4" flanges.

collectors: ive found some 3-1 collectors, but again, 1 1/2" diameter. anyone know of any that are smaller???

[Doubt_Incarnate]

you can check ebay for flanges they are on there sometimes, not sure about the specs tho, but priced for about $50 i think. good luck on collectors, you might be better off hammering a set around your pipes to make your own, at least you found some to begin with, i couldnt.

[RacerX11]

Whay are you going with 1-3/8" primaries? The Power Manual reccomends 1-5/8". The smaller primaries would be just big enough to match up to the size of the exhaust ports, IIRC. Idealy you need the header pipe ID to be slightly larger than the port OD to help prevent reversion (where is our header expert when you need him).

If you have access to a drill press and a bandsaw, you could make a set of flanges pretty cheaply. If you are dead-set on 1-3/8" primaries, I could probably make you a set of flanges.

Marty

[SappySE107]

Id go a little longer on the primaries as well if you can fit them. 1 1/2 is as small as I would go on that motor, unless you just want a low end torque monkey and don't care about top end. At that rate, 40+ inches on the primaries would be best.

[Doubt_Incarnate]

wouldnt the smaller diameter mean for a higher velociy, therebey increasing the scavenging effect? i understand that it is only to a certain point, and the target power and when it comes in has an efect.

[Guest]

After running my Hybrid with 1.5" primaries, I wouldn't go anything less than that. The next set I will build for it will be at least 1.625".

Marty you are correct.

[sharkey]

well, mabey i will go with 1 1/2" primaries. ive been told by a few people that the little 2.8l is good with tiny primaries. ive also read in several articals that its better to go to small than to big.

[SappySE107]

well, 1.5 is real small. I mean, you can't take that as you should run 1/2" primaries either. You have to look at the powerband and max power to determine lengths and diameters along with collector sizes. Tell us your goals and we can give you some specs to work with. 1.5 is still pretty small, though on a bone stock motor with no intent on upgrading the rest of the motor, its probably perfect.

[Quinky]

Has anyone messured the size of the exhaust ports before on the 3.1L/2.8L Aluminum head? Stock they are 1.20" in diameter.. Unless you are doing heavy porting according to header by ed and other reading I have done you wouldn't want to go with anything bigger then 1.25"... Iron head motors are even more restricted... My advice would be to port the cylinder heads first and find out how big they are going to be at the end and then use that to deturmin your primary tube size..

[sharkey]

im building up a pretty decent motor, hoping for around 200hp. im looking for some good all around power with it. from what i have seen with my desktop dyno, the motor itself will be a bit of a dog on the bottom compared to the top end, and i would like to bring the powerband back down a litle bit.

[Quinky]

Then you'll wanna go longer then 32" primaries steve..