[johnadge]

What is the best d port head, non ram air,no porting
& bone stock? how much of a difference (in e.t.) can
you expect from a port job?

[johnadge]

What is the best d port head, non ram air,no porting
& bone stock? how much of a difference (in e.t.) can
you expect from a port job?

[b-man]

The high-compression big-valve non-RA D-port heads flow essentially the same as the D-port RA heads. In many cases both RA and non-RA used the same exact head.

All of the high compression 400 and 428 head castings (12, 13, 16, 31, 48, 62, 670) flow pretty much the same, there is no real 'winner' in the bunch. There is a slight variation in combustion chamber size among them, ranging from about 70 to 80 ccs. Take your pick, run whichever one you have available.

Even the later low-compression heads with the 2.11 intake valve are pretty much equal to one another, but some will respond better to porting than others when it comes to full-race porting jobs (6X being one of the favorites).

How much ET can you gain from a port job? Impossible to answer since every engine/car/tranny/rear gear combo is different.

[Skip Fix]

I'll agree with B man. They all are pretty close. There are good and bad castings of each, and that seems to be the main difference in flow.

[Rugratman]

So how would you compare them with the Edelbrock aluminum heads ?
There is a HUGE price difference, Is the power that much greater ?
I am going to rebuild my 400 shortly and I am torn from using a set of Pontiac RA heads or going with the E heads.
Suggestions ??

[Half-Inch Stud]

The best D-Port head is the prettiest one, with the least rust wear on the external EXH ports, the absence of an Air-Injection boss, 2.11 valves, cross-overs filled, and already ported.

Cast Ident number is for display only.

"tbdET/1xxMPH/1.xx 60foot/28"/3.54:1/10"/469 #48/Flat HYD/DualQ-Jets/Offyl/3xx0Lbs
11.00/123MPH/1.50 60foot/29.5"/4.10:1/10"/469 #48/FlatHYD/DualQuad/Wenzler/3250Lbs<br />12.00/112MPH/1.61 60foot/26"/3.31:1/10"/469 #48/FlatHYD/Q-Jet/Torker/3650Lbs
12.70/103MPH/1.71 60foot/28"/4.10:1/12"/469 #48/FlatHYD/Q-Jet/Torker/3950Lbs"

[John Bailey (GTOKID)]

Like B man said only add I have picked up 4 tenths in a hyd cammed 455 with having the d-ports ported, Air flow makes a big gains but you need to have the combo to use it....Rug, the Edl heads will not slow your car down that much!! depends on what your combo and how fast you want to go. If you have RA IV heads don;t waste money to make the car slower. I love using round ports on street/bracket cars... but if you are going to run heads up you need RA V or call larry wensler.

[tom s]

the best D port head was and is the 63 SD 980 head

[GONZO]

I agree with mark in principle.
The 670 heads (screw in studs) ported would have a very slight edge over other d-ports. But as mentioned most Hi-perf (big valve)D-ports flow the same.

Edelbrock heads are great if you run a mostly strip only car and have a little more compression.Although I have a pair on the street, I have found they respond better to a bunch of performance mods as opposed to just swapping iron heads for them.

IMO ported iron heads are just fine for the street, and you can run 11's and 12's easily.

The 63 SD heads are great and exceedingly rare.

[Half-Inch Stud]

980 heads...know where a set sits outside.
eh, gonna let em rust.

[Old Man Taylor]

Tom S - Although the 980's are D-ports, I thought the center two ports were far enough apart that standard D-port headers would not work. Is my memory failing me again?

http://www.jimspontiac.homestead.com/Index.html

[Half-Inch Stud]

I recall; no EXH crossover.

Rather tall&wide intake openings.

"tbdET/1xxMPH/1.xx 60foot/28"/3.54:1/10"/469 #48/Flat HYD/DualQ-Jets/Offyl/3xx0Lbs
11.00/123MPH/1.50 60foot/29.5"/4.10:1/10"/469 #48/FlatHYD/DualQuad/Wenzler/3250Lbs
12.00/112MPH/1.61 60foot/26"/3.31:1/10"/469 #48/FlatHYD/Q-Jet/Torker/3650Lbs
12.70/103MPH/1.71 60foot/28"/4.10:1/12"/469 #48/FlatHYD/Q-Jet/Torker/3950Lbs"

[tom s]

Jim,out side center bolt are just a little wider,maybe 3/8 total,the 62 SD 127 heads are really almost as good,std. center bolt spacing and flat valves instead of tuliped.Nunzi says ported they are as good as the 980s.Joe Zajack runs 980s on his 63,Dave Johnson,Ric Johnson and a couple other Pro Nostalgia guys ran them untill the W heads came out.Tom

[tempest455]

Some of the Chicago N/SS guys still run the 980 heads and they are in the 9's. I picked Larry K's brain over a beer and brat one night at a test and tune. Some of them are running 15:1, 4 3/8" stroke cranks, 280-290 deg cams and .800+ lift.

9.90's @ 136 with a 4 spd. is pretty cool to watch with a big car like a Cat or Ventura.

Tempest455
http://www.wauknet.com/douthitt/

[Blackcat]

I'd give a Vote for the 67 O61 heads!
Testing a set myself now. Just had the Valve job and the screw in studs done.

Usually I'm found working on my Pontiac. If you want to find me Look for the white picket fence and all the old Pontiacs parked outside. And the half dissembled engine sprawled all over the driveway!

[ponchopete]

I just read in the new issue of HPP that Jim Yanoski went 7.98 @ 171.45 with d-ports. Damn! That's just sick.

Personally, even though it's a big chamber head, I always thought the 96 casting was a pretty decent piece. Just my two cents.

"My car would be fast if it had an engine, transmission, and rear axle in it."

[thirdgen455]

ummm didn't marty run #62 casting d-ports on his twin turbo motor?

http://home.earthlink.net/~saawatson/ my 1983 trans am. PONTIAC POWERED

[455Bird]

He did run #62 heads and I believe his fastest time that I can remember was 6.95 at just shy of 200mph.

1969 Bird 455
1868 Bird 400
1979 TA Turbocharged/455
1979 TA W-72 400/4speed

[Ken -Ace- Brewer]

Yes Jim did run 7's!! And 7 's was the perfect testing ground for our NEW Ultra Lite Billet Timing Chain! And acording to Jim it held up well!!
Be Cool,
Ace
http://pacificperformanceracing.com

ACE-P.P.R.

[Brian '74]

Yanoski, never liked him!! Anyway I heard Fulper built that motor!!