| Blocking intake heat riser [message #196833] |
Wed, 30 January 2013 07:57  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
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Ok, I've done as much research as I can although I'm sure there are more sites to dig through.
- I've found several treads that describe HOW to block the passages from pouring aluminum to installing block off plates.
- I understand that not blocking off the plates can result in the manifold heat boiling the gas from the carb (seen it on my own coach)
What I haven't been able to find is what happens to the original design functions of the GM engineers. As I think I understand, GM on most big block engines, wanted to heat the fuel air mixture to ensure better atomization. Without the heat, the fuel air mixture is inefficient with the cold engine...I assume the choke stays on longer to enrich the mixture??? So my question is really striving for understanding not questioning the wisdom of the folks who tell me I should do this.
I understand from some hot rodder friends that Olds (or perhaps aftermarket) had a phenolic spacer under the carb to address the excess heat problem. I know Chrysler made an entire phenolic carb (the Thermoquad) for this reason. Basically a Quadrajet but with a phenolic body. They worked great unless the body cracked or warped which was a problem. The secondaries were frigging HUGE and when you got your foot into it the Thermoquad on a 440 would moan like the hounds of hell and really go...while still getting decent mileage if you stayed on the little primaries. Again, similar but different from our Quadrajets.
Just wondering while waiting for the storm line to pass us by this morning. If there is a link to a discussion on this, please post it.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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