4 Hole Spacer

[1980RS]

I have not had a 4 hole spacer of any kind work well performance wise on a dual plane intake. The open 1" spacer has worked best for me.

[Horder]

I have not had a 4 hole spacer of any kind work well performance wise on a dual plane intake. The open 1" spacer has worked best for me.

Is that in terms of on the track? Or even on a street car?

[panic]

The open spacer is an open plenum (which is only a notch across the 2 sides in a dual plane), so both cylinder groups draw from all carburetor barrels... like a single plane.
Yes, the idle and low speed vacuum get worse.
Read my article: http://victorylibrary.com/mopar/intake-tech.htm

[GARY C]

Going to try a 4 hole spacer on my street only 327 in a 66 Nova. 10.3:1, aluminum head, 4 speed car. The 600 Double Pumper has the 1 9/16 baseplate. Should I use the same size holes for the 4 hole spacer or it likely wouldnt make a hill of beans difference??? Most spacers are 1 11/16.

Presently has a small open spacer on the dual plane Z28 intake and its a bit weak off idle in my opinion, considering the cam isn't too big and the timing is optimized.

Thanks in advance

Have you tested it without a spacer? I did a set of heads for a friends 327 with a standard performer intake and 750 carb and it lost almost 20 hp and ft lbs with and open spacer, it made 400 hp and 400 ft lbs with no spacer. It's hard to know if it helps are hurts unless you can dyno or track test it.

[Tom68]

Going to try a 4 hole spacer on my street only 327 in a 66 Nova. 10.3:1, aluminum head, 4 speed car. The 600 Double Pumper has the 1 9/16 baseplate. Should I use the same size holes for the 4 hole spacer or it likely wouldnt make a hill of beans difference??? Most spacers are 1 11/16.

Presently has a small open spacer on the dual plane Z28 intake and its a bit weak off idle in my opinion, considering the cam isn't too big and the timing is optimized.

Thanks in advance

1 11/16 spacer with a 1 11/16 base plate carb would be the fix for that situation.

[1980RS]

I have not had a 4 hole spacer of any kind work well performance wise on a dual plane intake. The open 1" spacer has worked best for me.

Is that in terms of on the track? Or even on a street car?

Mostly at the track lately. On the street I learned years ago when I ran a 350 SBC that sported a 30-30 Z/28 cam and an old Torker intake. While the car went like all hell the drivability was poor, I added a 2" open spacer and while the top end was better it still ran like crap on the bottom end. I then put on my 2" 4 hole spacer and the cars drivability issues went completely away, the car was fun to drive again. Now I did have a 4777 650 Holley DP on it at the time.

[jsgarage]

The boys at Engine Masters and Westech Dyno Services seem to favor Wilson Manifolds' 'composite' spacer This is a 2" tall 4-hole on the top and halfway down it transitions to an open spacer. They've done quite a few comparisons on Westech's dyno and no matter what brand of engine, the Wilson spacer increases power and torque.

But the key is to dyno the thing. You're flying blind without dyno tuning

[Tom68]

The open spacer is an open plenum (which is only a notch across the 2 sides in a dual plane), so both cylinder groups draw from all carburetor barrels... like a single plane.
Yes, the idle and low speed vacuum get worse.
Read my article: http://victorylibrary.com/mopar/intake-tech.htm

A lot of work went into that.

Can you edit it ?

[panic]

Yes, but the works in progress eat all my time.

[Walter R. Malik]

The boys at Engine Masters and Westech Dyno Services seem to favor Wilson Manifolds' 'composite' spacer This is a 2" tall 4-hole on the top and halfway down it transitions to an open spacer. They've done quite a few comparisons on Westech's dyno and no matter what brand of engine, the Wilson spacer increases power and torque.

But the key is to dyno the thing. You're flying blind without dyno tuning

Most Dynomometers only measure Wide Open Throttle power ... they give NO results about transition throttle openings or drive-abilities.

[Joe-71]

The dyno will tell you about torque curves if you use the 300 rpm/sec and different spacers. Spacers will show up big time if you take the time to test a lot of different styles and heights. We tested ~20 spacers and heights on our EMC engines, and had a few eye opening dyno pulls. The torque graph is the one that changed the most with the spacer changes. There is as much as 35 hp difference between running a strong engine(550-600+) without a spacer and adding the correct one on a dual plane intake. Joe-71

[BOOT]

Most Dynomometers only measure Wide Open Throttle power ... they give NO results about transition throttle openings or drive-abilities.

I came to the conclusion with my own basic test that some popular spacers, may make more WOT power than others but hurt drivability.

Since the OP said "street only 327", I would not suggest a tapered spacer and especially not a 2" version. Still every combo is diff and if the OP wants to purchase multiple spacers to try on his specific combo. There is a reason I & others have a pile of spacers

[Horder]

Ive been working on a divider filler plate to trial a pretty much fully divided plenum. A little more work and it should be good to try. Unfortunately here in Canada I wont be driving it for a couple more months…lol

[BOOT]

Don't forget there are cross flow paths on the bottom of your baseplate

[Tom68]

Don't forget there are cross flow paths on the bottom of your baseplate

Just enough to smooth the idle.

Can't believe I'm saying that when the standard rhetoric is that cross talk with dividers removed hurts idle.