[451stroker]

I have a rebuilt set of 6X-8 heads and was toying with the idea of having them ported before I install them. Are there any good head porters on this forum that do side work? The motor is a 467 with RAIV cam and 9.7:1 compression. I would like to get the intake flow to 240-250 cfm and the exhaust to 170-180 cfm. Valve sizes are stock.

[steve25]

How are you getting a 9.7 to 1 compression with the -8 heads?

By my math you need a total of 110 CCs of volume above the piston at TDC.

Also what are you planing on running for a intake manifold?

[Pav8427]

Keep in mind a port job after a valve job will probably require a touch up of the seats.

[steve25]

If you’re going thru the expense of porting the heads then a valve job should be done anyway. Not only to have fresh seats to mate up with your hopefully new valves, but because the factory valve job only uses about 94% of the given valves diameter.

For example with the 2.11” OD intake valve used in the 6X heads the stock valve seat OD is 1.98” or so..

A 1.98” valve seat OD makes for a curtain area of 6.21”, a 2.11” if used provides 6.62” .
The later provides 6.5% more flow area for any given valve lift used.

[78w72]

Following for answers to the OP's question...

[slowbird]

Paul Knippen here ports heads but he might be back logged. Finding people that do good work is getting harder and harder.

[Jay S]

These guys are on the east coast…


http://www.nitemareperformance.com/cylinderheads.html

[JLMounce]

If you're capable, it might be worth having a go at this yourself. Get yourself a copy of Jim Hand's How to Build Max Performance Pontiac V8's. There's a great section in there about what to do to the heads to get them into the CFM range you're looking for.

The economics of having heads ported these days aren't great. By the time you have the work done and build the heads, you could be into an entry level aftermarket head. With the RAIV cam you're running, a set of the Edelbrock D-Ports would be a great addition to the engine. Money might end up being a wash.

[unruhjonny]

Is SD back up and running after the last major setback - or has he thrown in the towel?

@ OP - sharing your location might aid you in finding credible porting options.

[tempest1964]

Several years ago (before the fire) Dave told me he was no longer doing factory cast iron heads. Only aluminum ones. Doesn’t Butler still do cast iron heads? http://butlerperformance.com/

[73T/A]

As I recall SD Performance was no longer porting cast Iron heads.This was announced sometime prior to the fire in 2023.I haven’t heard if they are up and running again.

[unruhjonny]

huh, I don’t remember reading that.
seems odd to - wasn’t that the backbone of his business for a while?

[ta man]

Originally Posted by unruhjonny

Is SD back up and running after the last major setback - or has he thrown in the towel?

@ OP - sharing your location might aid you in finding credible porting options.

He is working on getting back to up and running. Last time I talked to him he was finishing up the dyno and after that setting up the CNC machine.

[78w72]

Is porting pontiac heads different than any other V8 head of this era? If not, there are lots of companies that do head porting, from places that specialize in doing it with CNC or other machine shops that build race type engines & have guys that do it by hand.

Obviously research or talk with them for what you want, but a quick google search brings up quite a few places that do head porting and theres a place in the midwest that many shops around here send their heads to.

[PAUL K]

Originally Posted by 78w72

Is porting pontiac heads different than any other V8 head of this era? .

No ..... But it's helpful to know where the thin areas are. It's also hard to get a shop that specializes in one style of head to be enthusiastic about grinding on something else. Most guys in this industry have all the work they can handle. No need to branch off into something they're not familiar with.

[soupman]

Steve25 port heads too, you can PM him to discuss if he still does them. He ported my 47 heads to flow 255 with no noticeable loss in low end throttle response. He knows how to shape the runners and bowls to keep velocity up, the key to good low end performance as well as it pulls hard in the upper rpm ranges. More than happy with his work and knowledge.