I'm getting parts to do the 883 to 1200 conversion on my 2000 883. The Edelbrock heads look good to me with the square intake port and D shaped exhaust. Can NRHS work on these heads ? Or would the 04 Sportster heads be a better starting place ?
Thanks

We can work on the edelbrock heads but I'll be honest they really don't flow all that great stock. If you have not already bought them i wuld instead suggest a brand new pair of the new 04 Sportser heads. We sell them in 4 configurations:

Stock(with our stainless valves)- $743
Stage 1- Mild porting- $1100
Stage 2- Big valves, springs, extensive porting- $1400(our best street use)
Stage 3- Huge valves, springs, custom porting- $1650(these are race heads)

We have done testing on the Edelbrocks and they leave some things to be desired. The S&S Superstocks are not much better. They have a flat floor in the intake port which is not good for high flow. Harley has really done their homework with the new heads and they really do flow well!

OK, Thanks. I have not bought any heads yet. I have some more questions. If I use 04 Sportster heads, SE 575 cam and roller rocker arms can I use valves with the 7mm stems or do I have to go with the bigger 5/16 ? TP Engineering makes roller rocker arms that are forged and cheaper than the S&S rockers, do you have any experience with the TP Engineering rockers ? Can I use a set of beehive valve springs ( I just like that design) ? If I use 04 cylinders, 04 heads and 04 rocker boxes on my 2000 engine will the collapsible pushrod tubes designed for the 91-03 XL still work ? If I use the 04 rocker boxes can I still use the head breather setup I have on my 2000 (hollow bolt with a banjo fitting, a hose going down to a small filter) ? I know this is a lot of questions but this is confusing to me.

I have some more questions. If I use 04 Sportster heads, SE 575 cam and roller rocker arms can I use valves with the 7mm stems or do I have to go with the bigger 5/16 ? TP Engineering makes roller rocker arms that are forged and cheaper than the S&S rockers, do you have any experience with the TP Engineering rockers ? Can I use a set of beehive valve springs ( I just like that design) ? If I use 04 cylinders, 04 heads and 04 rocker boxes on my 2000 engine will the collapsible pushrod tubes designed for the 91-03 XL still work ? If I use the 04 rocker boxes can I still use the head breather setup I have on my 2000 (hollow bolt with a banjo fitting, a hose going down to a small filter) ? I know this is a lot of questions but this is confusing to me.

I would highly, highly, highly reccommend using a conventional dual spring with a damper with those cams, and doing it with the standard 5/16" valve stems.

Bottom line, there's no free lunch with a spring. A spring's pressure and travel (installed height minus coil bind height) are interrelated. Use a smaller wire diameter to get more travel and you lose pressure. Use a larger diameter wire to get more pressure and you give up travel.

One of the ways spring vendors work around this is to do dual or even triple springs. The vast majority of performance springs in the world are dual springs for this reason.

If you look at all the single wound springs on the market, including beehives, they either give up travel to a dual spring, or they have as much travel but they give up pressure.

That Screamin Eagle set they sell has larger wire diameter and therefore good pressure, and they picked up the travel by increasing the installed height. Since raising the tip of the valve is not a good option without other geometry corrections, they sink the spring pocket to get more installed height instead.

Well, sinking the spring pocket is not without it's own side effects. It makes the roof of the port thinner, and limits how much you can raise it. That limits how good of a port you can make.

IMO, you're much better off with a high quality high performance dual spring, than to go molesting your heads like that.

No, I've never tried TP rocker arms. I suspect they're made by someone else, possibly JIMS? I've broke plenty of those.

No, collapsible tubes designed for 91-03's won't fit on the rubber mounts. We have collapsible tube kits for the rubber mounts, though.

The rubber mounts use the same head breather arrangement that the 91-03's use, so that's not an issue. The '04 rocker boxes don't have a vent in them like the XB rocker boxes do.