1 5/8" headers vs 1 3/4" headers on a 347cid

So with ported vic jr. heads and a solid roller 254/264@.050 and 621/621 on cl of 106

What headers on a strip/street car?? 1 3/4 or 1 7/8, I have already purchased a set of Kooks 1 3/4 and had them Jet-Hot coated for a total of $1100.00. I hope i can get by with these.

Let me know guys??

thanks for the info.

I just put on a set of FPA stepped long tube headers (1 5/8 to 1 7/8) on my car and it really opened it up. They are ceramic coated and ran about $700. On the street, the car has gobs of bottom end torque and is real fun to drive. On the track, it runs 11.40s shifting at 6,500 rpms and is still breathing pretty good through the traps. Of course this is going from some Tri-Ys so it isn't really a fair comparison. But I think running a stepped header is the way to go for a street/strip car. With more boost, these headers are capable of handling upwards of 800 horsepower from what the guys at FPA told me.

The header pipe needs to be bigger than the exhaust port and not blended in to help stop reversion with big overlap cams.

Originally Posted by BIGJOE

I for got to mention, this 347 runs 10.98 at 122.5 in a 1965 Falcon. with a C-4 with 4.56 gears and a 10 by 26 inch slick. He goes through the lights at 76-7700 RPM(and the small headers)
JOE SHERMAN RACING

It would go even quicker with bigger pipes. Min 1 7/8

there's more to headers than tube size alone. Shape, bends, collector design, what's behind the header, collector size, etc.

Agreed!!!

Question for JOE SHERMAN, was your testing mostly with strokers, or have you also tried different size headers on 289/302s? The smaller cubes would probably allow for smaller primaries at any given RPM, or shift the RPM range for each header size up. Just curious because on my 289 I have 1-1/2" long tubes and I shift it at about 7300rpm. I think 1-5/8 would be about optimal for my combo but probably not giving up much top end with my current headers given the small cubes.