[lust4speed]

Ended up with a nice Holley Street Dominator manifold mixed in with a recent purchase of bulk parts. While I found the height listed in one of the old threads (same as stock Pontiac) I didn't find any comparisons to how it faired with other manifolds. It "looks nice" and ports align well, but is there some performance deficiency I should know about? Would be tried on a mild stroker running an Old Faithful sized cam, Quadrajet, and headers. Where does it fall in the performance list like compared to a Tomahawk or Torker I? I suspect it would also benefit from a spacer and being stock height there should be room.

[Dragncar]

That is the intake the Tomahawk was designed after. A Dave Bishop ported one. The Tomahawk should run better than the as cast HSD.
I have both. The Tomahawk I have was worked over some by Dave.
I bet if someone took a fully ported wide port Victor and did the same thing, copy them in China they would sell.

[Skip Fix]

As he said Tomahawk copied from an SD modified Holley. O the 455 in my 78 an SD modified Holley dynoed the same as my modified Torker II.

[Held for Ransom]

One of the 3 design looks of the HSD. Look for cracks in the intake runners.

[tom s]

Mick,I have one on the 455 in my 69 bird.SP II cam and 3310Holley.For the gearing in my car I think I might swap a Perfomer.3.31s in the back and a .67 OD.Around town I’m 1400 RPMs or so and 2000 on the highway.I think the engine will be more happy with a dual plane.Tom

[steve25]

I have never flow tested one to make any comments in that regard, but for any mainly street motor it’s better then a T1.
It has a smaller plenum then a T2 and would welcome a 1” or better spacer on motors of 428 cid or greater.

[Steve C.]

I will suggest you have no interest in running a Victor intake... However, for interest to point out the potential of a properly worked HSD intake.

I did some back-to-back dyno testing with the two intakes. The HSD intake with my HP950 carb and a 1/2" open spacer made 589.4 hp at about 5700 rpm on the dyno, this was on a previous pump gas 4.210 stroke 462cid street engine. With the same engine & carb my Victor intake with 1/2" carb spacer made 600.9 hp at 6000 rpm. Both intakes had a port entrance opening about 2.300" tall, and were properly port matched to the cylinder heads in use.

HSD / no carb spacer:
577.9 hp at 5700 rpm, 581.0 ft.lbs. at 4400 rpm.

HSD / 1/2" open spacer:
589.4 hp at 5600/5700 rpm, 589.0 ft.lbs. at 4600 rpm.

HSD/ 1" open spacer:
589.8 hp at 5700 rpm, 590.8 ft.lbs. at 4400 rpm

I know peak numbers don't express the whole story, really need to look at the curve with each different spacer. A bit of clarification and related to the numbers I posted. The HSD intake I used was not your run of the mill intake, it was modified by Dave Bisschop with plenum and runner work. And probably VERY similar to the prototype that Dave did for the production Tomahawk intake. Except note the Tomahawk intake as cast for marketing reasons does not have the large port exit openings in order to be used on 'factory' cylinder heads.

Side note, regarding Skip's post #3. He borrowed my modified HSD intake for his testing with the Torker II intake.
.

[unruhjonny]

iirc the HSD was considered a mid rise single plane intake;
It IS a smidge taller than the factory intakes, and it works with second gen Trans Am shakers;
If my memory serves me, it allowed me to close my Formula hood when I briefly ran it in 1996(?).

I believe that this is a grossly under rated intake - it's been long discontinued.

[65 Lamnas]

Originally Posted by lust4speed

Ended up with a nice Holley Street Dominator manifold mixed in with a recent purchase of bulk parts. While I found the height listed in one of the old threads (same as stock Pontiac) I didn't find any comparisons to how it faired with other manifolds. It "looks nice" and ports align well, but is there some performance deficiency I should know about? Would be tried on a mild stroker running an Old Faithful sized cam, Quadrajet, and headers. Where does it fall in the performance list like compared to a Tomahawk or Torker I? I suspect it would also benefit from a spacer and being stock height there should be room.

You'll just have to try it. Jim Hand's combo didn't like it very much, I think he lost .2 in et and about 2mph.....YMMV

[Skip Fix]

The Tomahawk flow with a 4 hole carb and a Q jet are totally different. The Q jet primaries are so close to the front runner the air needs a spacer to make the turn. Square bore the primaries are a little further back so not as bad.

[PAUL K]

Nice looking intake manifold

[Dragncar]

I was able to run 11.00 with Tomahawk. About a tenth and a half slower than my Warrior. Its a pretty good intake for iron heads IMO.

[Cliff R]

Skip is correct about square flange vs spread bore on the Tomohawk intake, or any other single plane intake. ALL of them require a spacer to make best power. With a Q-jet or TQ the huge rear secondary throttle plates stick too far into the plenum areas and will cause substancial power loss. Even with a square flange carb they love a spacer to get them up out of the plenum some.

I've tested quite a few single plane intakes, dyno and at the track, and wouldn't use one without a well blended 1" spacer on them.....FWIW

[lust4speed]

Originally Posted by Steve C.

...
HSD / no carb spacer:
577.9 hp at 5700 rpm, 581.0 ft.lbs. at 4400 rpm.

HSD / 1/2" open spacer:
589.4 hp at 5600/5700 rpm, 589.0 ft.lbs. at 4600 rpm.

HSD/ 1" open spacer:
589.8 hp at 5700 rpm, 590.8 ft.lbs. at 4400 rpm
...

Interesting that at least with the peak numbers the manifold didn't care too much about the additional 1/2" height. I know there is a lot of stuff going on but wonder whether it was approaching adequate plenum volume? Kind of a mute point since I only have a couple 1" spacers laying around.

Were the ports taken out to RAIV size (FelPro1233) or just cleaned up to match a standard intake gasket for the tests?

[Lee]

FAST EFI testing intakes, very mild 455.

[Steve C.]

Mick,

Regarding my HSD intake mentioned in post #7
The ports are larger than a RAIV size (FelPro1233)

The tallest port opening height was about 2.300" and it had about 0.250" above for a gasket seal. The widest port was about 1.140"

With it I used the SCE intake gasket number 128103.

Regarding that specific gasket, the dimensions listed in both their catalog and online have been incorrect in the past, and I wouldn't be surprised if they haven't been changed.
I've ordered and used quite a few of them over the years and each and every one has measured about 2.320" tall port opening.
The actual port opening width on that gasket is about 1.170" or 1.180", not sure which.

Side note: The Victor intake manifold mentioned in post #7, as with all my intake manifolds, uses that gasket.


.

[steve25]

In the results posted in 15 was any jetting changes made to try and max out power?
If not that’s a shame!

[Lee]

Originally Posted by steve25

In the results posted in 15 was any jetting changes made to try and max out power?
If not that’s a shame!

No jets, it was with an EFI system that kept the AFR right 12.8.

[steve25]

Oh got it, thanks!

[PAUL K]

If you decide you want to whittle on one this will make 600/600 with iron d-ports.