[David Holmberg]

Other than the chambers (and plug angle) the heads are the same as the normal E-heads. Many have upgraded to roller springs without any issues. In fact I don't think I've heard of one issue with the valves supplied by Edelbrock.

[Skip Fix]

Dave I agree on the valves, but if you check with Edelbrock tech they will often waffle if they are OK with roller spring pressures.
Ferrera makes many of the Edelbrock valve but to Edelbrocks specs-and they won't tell you which ones.

That is part of why on my '09 project we used a custom Manley intake and cut down a Pontiac Ferrera 6000 exhaust valve to 1.72 for it. All of my Pontiac E heads have gotten either SI or Ferreras.

[77 TRASHCAN]

Originally Posted by 900HP

Here they are semi-finished

Mark,
How did your headers compare to the chassis models???

The standard wive's tale is that one installs tri-y's to pickup low RPM power, somewhat sacrificing top end...??? (especially for a street driven vehicle)
I've seen the opposite happen on a SBC engine. I had a 292 cid (283+.060) built for a driver. Was blessed to have the builder give it a whirl on the dyno (this was 1985 mind you). He tried a set of tri-y's on my engine, that had also been tried on a 355, and 406. Each engine responded the same... sacrificing low end and making more top end...compared to his standard 4 into 1 chassis headers that he ran on every SBC he tested....
Thanks!

[900HP]

Let's not muck up this thread anymore than we already have. The 4-2-1 headers when properly designed and built will make a much wider power band than a 4-1 with no downsides. There is so much to header design I don't know where to begin and I'm only at the tip of the iceberg.

As far as our 4-2-1's to chassis headers? There was no comparison. No comparison at all.

[AC445]

Hello all,I called Edelbrock tech again and asked if 61515 is going to be available bare.They said not that they knew of,but they did tell me this head uses MPI valves.Does anyone know how they compare to Manley or Ferrea? Thanks

[ponjohn]

Are the springs still of poor quality?

[shaker455]

I see Butler offers these 65cc as cast heads as well & will port & fit with valves...not a bad deal is they have them in stock.

I used an out of box set on a 462 & did pretty well...560hp & 600Tq

[Half-Inch Stud]

Would be dramatically informative to run those "Long Ys" on a DYNO, then the 4- tube, then PMD Long-Branch:to generate BSFC maps with constant HP curves.

Comparison would propel our Hobby ahead in all Street, and most Strip concerns.

[cgeise]

Originally Posted by shaker455

I see Butler offers these 65cc as cast heads as well & will port & fit with valves...not a bad deal is they have them in stock.

I used an out of box set on a 462 & did pretty well...560hp & 600Tq

In stock is the key -- Edelbrock it terrible at delivering product any more --really bad.

[Overkillphil]

shaker, did you use the 65cc ones on the 462?

[shaker455]

Phil,
No, I had the out of box 72's fully assembled