carb spacer question

[64gal500]

Hi, I'm having some heat soak issues and I'm wanting to install a phenolic carb spacer under my carburator ,but not sure which one would work best on my car, 4 hole or open.I have a 390 with a Luniti VD-FE-284 cam, Holley 750 carb  with vacuum secondarys on  a streetmaster intake,headers,D2t heads,4speed,with 350 gears in a 64 Galaxie, any advice would be appreciated.thank you

[Drew Pojedinec]

In my Galaxie I had a lot of hood clearance issues and heat soak was an issue.

Things I did to help fix it:

1.  These gaskets: http://www.summitracing.com/search/brand/edelbrock/product-line/edelbrock-heat-insulator-gaskets/gasket-thickness-in/0-320-in?N=400065%2B300028%2B4294863017&SortBy=BestKeywordMatch&SortOrder=Ascending&autoview=SKU
This require some cleanup work, but they are just like the old gaskets for Autolite carburetors and they work well.  This helped some.
I would have loved to use a big ole 1 or 2 inch spacer, but I just didn't have the room under the hood.  Since you have a streetmaster intake, I don't really see a four hole spacer having any sort of better effect than an open spacer.

2. Blocked Exhaust heat crossover in the intake.  This helped more

3. Ran Stainless steel braided hose (-8 in my case) and an electric pump.  This way the fuel doesn't need to go into an engine mounted fuel pump and pick up all that heat there.

4. Make sure you have a strong battery and starter

[Ratbird]

I had the same issue when I went to an aluminum intake. I just used the least expensive 1/2 inch one I could find and made sure the gaskets sealed completely. Worked great.

[Fine69mach1]

I have a 432 stroker with a porter streetmaster and saw good  gains in horsepower and torque by adding a 1" open spacer under my 750 Holley  Dbl pumper.  Had increase with a 4 hole spacer too but the open spacer with the ported streetmaster plenum was the best for my motor.

[64gal500]

Thanks for replying, I forgot to mention that the exhaust crossover has been blocked off. I'm thinking that the open spacer has the most favorable reviews but still undecided.

[jayb]

I tested various spacers for my book. The Streetmaster preferred the open spacer on the 390 stroker dyno mule, giving an 8 -10 HP improvement at the top end with no loss in the midrange.  However, at the lower power level of my 428CJ (around 425 HP), the Streetmaster did not care what spacer was used; the spacer's didn't help.  The 390 stroker engine was higher HP (around 480-500 for most of the good intakes), so it kind of makes sense that on that engine, more plenum volume would help the Streetmaster.

[64gal500]

Thanks Jay. I was hoping you would chime in on this.I know you spent countless hrs testing just this type of thing . And thanks to everyone else for responding to my post.I value everyone's opinion.looks like a open spacer going on it.