You speak the truth!!!

Then again, if everyone got JMM gear there wouldnt be as much road fodder to decimate as there is now.

Thats exactly right you get what you pay for.
And it always pays to resurch anything before you hand over your hard erned cash. I too thought JJM stuff was a bit over priced and high on power for what he did then I drove a dev5 powered ute and I was conviced. And I've said it before those how put JJM product down either don't have and can't afford it or only buy bit's and pieces of it then say it's s**t cause it didn't give the power it promised, You have to use the complete package to make it work.
Hope this helps some to make a decision for or against the JJM product I know it works and though's who have it on this forum and others know too.


My 2cent criticize me if you wish I really don't care anymore

A quote from the highly respected A Graham Bell, authur of Performance Four Stroke Tuning regarding exhaust headers

Why unequal length primary pipes? Well, this tunes the torque peak in each cylinder to a different RPM, thus flattening and smoothing the torque curve. It tunes out that sudden rush of power, so instead of the engine coming on song at, say, 6250rpm, the torque peak will be lowered slightly but may go all the way from, say, 5500rpm to 6500rpm. Hence one cylinder may peak at 6000rpm, another at 5750rpm, another and 5500rpm and still another at 6250rpm.

To achieve this the primary lenght would be adjusted to minus 2" plus 4" from the ideal length. Therefore if the correct length was found to be 29", the four pipes would vary in length from 27" to 33". in reality I prefer unequal length headers in most aplications. For a long time it was thought that equal length tuned headers were the best way to go, but when it was discovered in installations where equal length pipes just would not fit that the package often became more driveable, some tuners slowly came around to acknowledge the advantages of unequal length pipes.

This has been taken with the utmost respect to the authur and is strickly for the benefit of all.

Although the headers discussed were for a V8 the same pricniples apply to the I6. From another section in Performance Four Stroke Tuning it is stated that the ideal pipe length for and engine tuned to peak produce peak torque between 4000-5500rpm and with the EX valve opening between 50-65deg BTDC (50 being fairly close to std and 65 being a fairly worked cam) should be between 32.6-49" total length(shorter length=top end and longer=bottom end). This can either be the single primaries or the combination of both the primaries and the secondaries, however the primaries need to be of at least 13" in length if they are of the combined calculation.

Therefore with the JMM Race series headers with thier 13-19" unequal length primaries and a total length (primaries + secondaries) of 39.3-45.5", they are perfect headers for your 4ltr falcon according to A Graham Bell and also the boys of Headers By Ed, a custom race header shop in america. See www.headersbyed.com

Back to the dyno runs, HMS charge $160 for a dyno run & a tune.

Good researching done there Jaysen

Yes but guys doesnt matter how much you try and tell them and give them proof they just wont listen thats why i gave up on the 6 cyclinder section of the site they ask a question you answer they still dont care lol

Yep know exactaly what your saying spider