Phenolic Spacer

[68X426]

After a hot week at Reno,    it is now obvious that I'll be needing to add a phenolic spacer.

Question: what's the difference between the 1/2 inch size and the 1 inch size for performance and heat displacement? (besides the clearance and linkage issues).

Are all brands the same? (I've seen them from $11 to $50 and they look the same  ). Thanks.

[1BAD68]

Just installed one and tested it out today.
I read that after a long drive on a hot day that you could put your hand on the carb and it would only feel warm.
Its 82 here and my carb is hot, not like before the spacer but still more than warm, although its an Edelbrock 1/2" phenolic so I can't respond on the 1" spacers.
The reason I went with the 1/2" is because everything I read said the performance gain from them is basically insignificant, so I mainly wanted to reduce some heat to the carb.
I only paid 12 bucks on Ebay so I guess its worth it.
My fuel filter use to be empty after I parked the car from the heat expanding the fumes, but this time its about 3/4 full.

[68X426]

Thanks for the input. I'll add that by performance I meant drivability and dependable start-ups at High Noon on hot days.

Is 1/2 as good as 1, would two 1/2s be better than one 1?

[1BAD68]

I'm guessing a 1" would keep it a little cooler than a 1/2' but two 1/2's would not be good due to the chance of vacuum leaks (too many gaskets)
I parked my Charger about 40 minutes ago and just checked it. The carb is pretty hot, I can only keep my hand on it for about 10 seconds before it feels like it would burn.
But the filter is now almost full.

[1BAD68]

Took my infrared thermometer just now and...
Cylinder head = 172 degrees
Aluminum intake = 151
Carb = 128
Not as cool as I thought it would be.

[68X426]

Update: the motor only has clearance for a 1/2 inch thickness, so that's what I ordered. I'll report back if it works.

[firefighter3931]

A 1/2in spacer will do the same job insulating as a 1in spacer. 

As for power increase....it's combination dependant. Some engines respond well to increased plenum volume (open spacer).....others respond to a stronger signal (4 hole spacer).


Ron

[Manifold]

I will say that I put a phenolic spacer on my 383 first (heat cross over not blocked yet) and it did not make much difference in keeping the carb cool (based on touch; no temperatures taken). Once I blocked the heat crossover (for an aluminum intake), I can touch the carb (Carter AFB) and not feel like my hand is going to burn.

The bigger bang for the buck was blocking the crossover. I'm sure both are very helpful (have always run both on my big blocks).

[greenpigs]

 I can't remember where but one of the manufactors recomends blocking the heat riser or it could warp the spacer. I have not put the valley pan on yet with the heat riser blocked off so it may not be doing as well as it was intended.