This response below got long, but please read it before you block the intake heat on a stock engine. Then read it again another day.
Will this one thing make a difference?
yes it will make a big difference, and probably not go well.
Your choke that worked perfect will not come off on Time and is now rich, plugs will be dark or fouled depending on the car.
when you stab the throttle the car will hesitate, buck and snort, possibly backfiring out the carb. You won’t be able to pull out in traffic.
The factory and most aluminum street intakes have a heat crossover because the heat is needed to atomize the fuel. If you block it you are going to have more problems than advantages.
I want you folks to know about these disavdantages. I live 2 hours from Canada. It’s cold here in the morning and nights Most of the year. its 80-90 in the simmer for 3 months. If you live in a god forsaken place like phoenix or Vegas in may work great. Now maybe it can work on a stocking car in 40-50 degree temps. But usually when this is brought up it’s a short blurb and no description, nobody explains about How to make ot work. They do says block it and you gain so much. Not really. so explain how many fixes they had to do to the car to make it work and drive good and see a gain. I’ve talked to folks who have made it work. On a stock street car, Not a small task.
I tried this heat crossover block mod on a car is was drag racing. But the car was and all stock: 440 magnum on a gtx. AVS carb, stock cam, stock intake and exhaust. 727 stock converter, 3.55 rear, sticky tires so no tires spinning. The car would run 14.0 at 97 mph consistently.
Was a great car to drive. So I wanted more and blocked the heat and it was a pig with the problems described above.
Now if you drive the car for a half an hour or more or got it warm and parked it & let the heat soak into the intake it drove almost as good as before. Car is telling you it wants a heated intake. I took thone blockers out and never looked back.
I think this heat blocking mod works better on a built up engine or all out racecar. You will notice tall single pane manifolds dot even have a heat crossover passage. Seems the high compression, big duration cam, 3000-5000 stall converters, and race fuel system doesn’t need it.
guess what, a max wedge doesn’t have a heat crossover and they haul The mail. well its a race engine from the factory.
last idea To ponder. Many have been here. Have you ever has a small block mopar with the heat crossover plugged with carbon? Doesn’t run or drive well does it. It runs like crap Stalling out, bad throttle response. Choke too rich. So you work on the carb, tune it up, not much help, still runs like crap, customer not happy. Now you pull the intake and clean it out and it runs like a different car. And you didn’t do anything more to the carb or ignition, because it was never the problem.
