Ok, I did some searching in the forum and didn't fully find an answer to my question...

I have a new Edlebrock Performer intake and Edlebrock carb on my 390... Do I need a spacer between the carb and intake to prevent "percolating" or flooding when the engine is hot? You may ask "does it flood now?" I don't know because I haven't fired it up yet after a complete rebuild.

Thanks in advance!

DD

 

Yes, the heat insulation is highly desireable.

 

But not required by all setups. Also an solid aluminum spacer is worthless for this. You will need either a phenolic spacer or on of those gasket/aluminum thin flat spacer/gasket/ aluminum spacer set ups. I don't and won't use Edelbrocks carbs so I don't know how sensitive they are to this but none of my Holley carb have ever needed a heat blockin set up.

 

Here are some good articles about spacers. Check it out then google carb spacers.

Carburetor Spacers
Carburetor Spacers - Review & Comparison - Tech - Hot Rod Magazine

 

I always liked this one.

http://shop.oreillyauto.com/ProductD...goryCode=3339T

It seems my favorite heat shield has be discontinued.

 

The best I can gather is that I really don't need a spacer. I wasn't too concerned about the power advantage as high revs out of a NP 435 and t-case isn't my MO for driving practices. Unless I'm missing something important, I can now concentrate on getting it back together and running again.

The heat build up and transfer seems to be present in stock cast iron manifolds and aftermarket carbs that don't have the coolant crossflow like the stock units. If I do end up with a restart problem down the road, I think I'll fab my own spacer from a wood source.

Thanks!

 

Just throwing it out there, but intake manifolds that do not have the exhaust crossover are less likely to cause vapor lock. If memory services, the Edelbrock doesn't have the exhaust crossover.

However, if you're just putting it together, it can't hurt

 

Better for streetability to have the crossover and factory spacer. Also better to run the FE at 190* less wear on rings and cylinders. Trick is a good performing choke and well tuned carb. 2 cents/

 

First, I think the Edelbrock Performer intake DOES have the exhaust crossover, and I think the RPM does not. I had the same set up on my 360 F100 4WD and it tended to boil the fuel in the carb, not flood it. I live at about 3,500 feet, which lowers the evaporation point, I also had a real spike in the problem when I bought some gas with high ethanol content.

Hot weather start-stop driving, and coming to a stop after running at higher speeds would cause severe loss of power and stalling. Once the engine cooled off completely it would run fine for about 35 minutes. I was negotiating the purchase of a really nicely built 410 to drop into the truck, and the fellow who had built the 410 suggested that it was boiling the gas in the carb. A friend who was with me had a spacer and I put it on. The problem almost completely went away, but I suspect that Bear is right - the one I am using is pretty solid aluminum and one with better heat insulating characteristics would have completely solved the problem.

I am now running a 390 GT cast iron intake on the 410 (it is port matched and has better flow characteristics than the Edelbrock Performer) and with the spacer I did have one incident after running at high way speed and coming to a stop on a very hot day, but when I picked up a little speed it resumed running normally. I may take Bear's advice next summer and put a different spacer in.

 

My "performer 390" did NOT have the crossover.

 

I'm running the Performer 390, so if Krewat is correct, I shouldn't have the problem. I'm going to call Edlebrock next week and ask a tech there. So I will post their 2 cents on this matter...

 

You are correct. I have both of those intakes and the performer 390 definitely does have the crossover and the RPM does not. I ran the performer with gaskets that blocked them off.

I did not have a problem hot starting with a Holley carb.

Good luck with your new motor 71_4x4_390.

 

(Just a general comment not specific to yours.)
Most of the referance to spacers concerns heat insulation but what about the other benefits with carb spacers? Up here in WA any carbed truck would have trouble with out adding heat. Not saying that some don't with success (so I don't get ripped LOL). Just saying there is a lot more to the issue. Also there are good performance considerations.

"I did not have a problem hot starting with a Holley carb."
I would think not as your not adding any exhaust heat to the manifold. But I would have a hard time getting it to warm up in the winter.

 

I call Edlebrock and was told while it wasn't necessary, it was recommended that I use p/n EDL-9266, 3/8" heat insulator for my set up.

Calling Summit right now...

 

Kennewick, 190 deg. F less wear on cylinders, I may be confused with wear verses performance? I run my 390 with a 160 deg. F thermostat. It will defrost the windows but, I may still wear my jacket in the winter. In the Summer time I ran it at 90 mph for five miles and it was around 180 deg.F. As soon as I slowed down, the temp. gradually fell off to around 165-170 deg F..The optimum temp to run is around 170 to 180 deg. F. Every 10 degrees F. lower than 170 deg. F it is like adding 1 octane to your gas. Just my opinion and what I have learned. I have heard debates on higher operating temps verses lower operating temps., goes both ways.I have seen charts on both sides.I know for performance cooler is better, eg, Aluminum metals used, inter coolers on turbos,oil coolers, trans coolers, cold air air intakes, cowl hood scoops, etc.Everything that I have mention is to lower engine temperatures.Modern vehicles run higher engine temps only for emission regulations, keeping oil vapor and other gas vapor going into the intake system to be burned again or evaporated before it exits the exhaust.In the winter I can let my 390 run from a cold start up for 15 minutes and it may be at 160 deg. F. Now the oil pressure after 15 minutes is at 20 psig. so I know the oil is at operating temp. instead of 65 psig. cold start up.So could you explain this 190 deg. F. to me. I might like a 190 deg.F thermostat in the winter for driving to work. Only for the heating purpose of the engine temp.(heater only).You may be having start up problems because of the 190 deg.F operating temp.. What do you think your engine temp. does when you shut the motor off after reaching say 190 deg.F? Do I hear say 200-210 deg. F now, VAPOR LOCK, boiling gas, etc. Here is some data to look at:BOILING POINT/85 DEG.F, 29.4 DEG C FLASH POINT/ -50 DEG F, BOILING RANGE FROM 32-210 DEG C, VAPOR PRESSURE 304-684 mmG @ 37.8 DEG. C,LOWER FLAMMABLE LIMITS 1.496 BY VOLUME; UPPER FLAMMABLE LIMIT 7.8% BY VOLUME/ 56-60 OCTANE, 92 OCTANE, 100 OCTANE. Do you see that the boiling point is 85 deg. F? Flash point is -50 deg. F.? Pressure of the gas in fuel lines, fuel injectors, fuel pumps, decrease these numbers considerably. Think of it like the concept of a pressure cooker. Just something to chew on, zrxlover. I don't think you are flooding, you may have to flood it to push all the vapor out of it because of the heat in the carb and fuel lines has vaporized.Ask the manufactor if a spacer is needed, some are designed for spacers and some are not. I perfer asking a engineer who designed the intake rather than guess. Spacers do more than cool incoming gases. Sometimes it changes the rpm range of intake, depending on the deck height of the intake and how tall the spacer is. Check clearance issues and manufacturers suggestions first. And kennewich I was not attacking you, I know you said that was just your opinion. I was only trying to give some technical information to all who are interested, zrxlover.