Filling in heat crossovers

[DoubleV]

How many of you guys have done an actual before and after comparison between filling the heat crossovers and leaving them open? What were your results? I'm familiar with the theoretical benefits of filling them in, but would like to hear of ones real life experiences.

 

[-83MONTESS-]

Im glad this was brought up im curious aswell

 

[Bar50]

Did it for a Pontiac motor for a '70 GTO I used to have, not sure I could tell that much (in that I never had that motor in there without the cross-over work). The procedure at that time was to melt old pistons and pour/fill in the cross over from the port side and blend it to match. Looked cool, was tougher than I thought. I did it because that is what all of the Pontiac performance guru's I spoke with advised me to do....pre-Edelbrock heads.


Maybe I will ask, on or for what application? With what intake?

Mine set-up based on a FAST drag car blueprint/build, Factory Appearing Stock Tire....

 

[DoubleV]

Maybe I will ask, on or for what application? With what intake?

For me it will be for the engine in my pic, but I will also be raising the CR to around 9.3-9.5ish, installing a bigger cam ( I'm leaning toward the Ultradyne .485 lift, 217/221 duration, 110 LSA cam ), and a good cleanup on the heads, most likely with bigger intake valves too. Car is a warm weather 'fun' street cruiser with a few trips to the track here and there. Goal is very good street manners, reasonable gas milage, reliability, and as deep into the 13's as I can get while reaching 100 mph trap speeds when racing it.

 

[RegalBegal]

I did it on my Buick 455 running an Edelbrock intake, the carburetor would get very hot on shutdown, leading to hard starting and like a 20 minute wait to cool down. :shock: Plugging the crossovers was the cure.

 

[DoubleV]

I did it on my Buick 455 running an Edelbrock intake, the carburetor would get very hot on shutdown, leading to hard starting and like a 20 minute wait to cool down. :shock: Plugging the crossovers was the cure.

I too suffer from hot starts even with a 1/2" phenolic resin carb spacer. I attribute it to todays crappy gas. If filling the crossovers did absolutely nothing other than solve this problem, it would be worth it for that alone. Of course I'm liking the idea of better performance, but always get conflicting stories of it's actual worth. I have heard everything from 'no gains at all' to 'massive and very noticable' gains. I've heard 'takes forever to warm up even in the summer' to 'it only takes a couple more minutes to warm up and drives perfect'.

 

[Minion1186]

Doesnt edelbrock make crossover plugs for oldsmobile intakes? I've heard from some that they stay in place and others say they can hear them bounce around in the heads.
http://www.summitracing.com/parts/edl-2733/overview/

 

[Blake442]

I don't know where Edelbrock gets the audacity to say they install with no modification... :lol:
Took my buddy that built my 455 a few hours to get them strategically ground down enough for them to slip in flush with the head.
I was going to have them filled the old-fashioned way when I had the heads redone, but the guy who did them accidentally dropped and broke his ladle and couldn't melt any metal, so we just used the plugs that came with my intake.
I don't have a before/after comparison, but I have no issues with hot starts and I have no carb spacer.

 

[DoubleV]

I have some of those Edelbrock plugs. They came with my RPM intake, but filling the crossovers in the head allows the headers to better scavenge the cylinders. Besides, with the stories I've heard about them rattling I wouldn't even want to take a chance.

 

[olds307 and 403]

Like Blake said those Edelbrock plugs are not drop in. I had to grind mine a lot to fit in the #8 heads. You are doing work to the heads anyways and drive only in nice weather, makes sense to me.