Hi just trying to learn a bit here. On a 66 Toronado 425 with B heads, how beneficial is it really to block off the exhaust crossover? Is there any risk? What are the real drawbacks? I'll be building the engine for daily driving but not below 40 degrees. I want to build it mainly for durability but of course would not mind a little extra pep. Thanks in advance for any helpful advice.

 

It's not beneficial for anything other than drag racing, and it will run poorly for longer until it warms up.

 

^^^This. Blocking the crossover is a drag racing trick where the smallest advantage helps. You need to rejet the carb to take advantage of the slightly denser inlet mixture anyway, which few people really do. On the street you will never feel a difference. Owners of trailer queens do this to prevent the paint from burning off the intake manifold, but all they care about is driving the car from the trailer to the showfield.

 

If it still has orig divorced choke that wont work with a blocked crossover

 

Ah, and it does and I plan on keeping that so this is a no go.

 

you’ll need to use an electric choke from a later Q jet, it bolts right on.

blocking the heat crossover IS a good idea. it’ll reduce heat soak problems and hard hot starts, reduce or eliminate percolating fuel in the carb , reduce the tendency to ping , cooler under hood temps while providing a cooler intake and a denser air/fuel charge..it’s all good.

cooler running, more TQ and hp and happier engine. Olds had reduced and manually optioned heat crossovers over the years, 66 tripower intakes, D and F heads. they weren’t race cars. they came with a warranty and were designed to be driven year round,, they had chokes and a warranty like any car.

to be honest, you wouldn’t even need a choke by what you say … a couple of pumps and it’ll start.

the 66 toro 425 is a high performance engine, treat it like one.

 

An integral choke housing bolts right onto a carb with a divorced choke? Are you sure about that?

 

Ok so what type of choke is this, and what is this box mounted right on top of the crossover. Is there a thermostat in there?

 

yes. I’ve done it with parts from late style electric choke carbs.

you can also buy kits..there are many out there. personally I wouldn’t bother with a choke again at all. for the one or two minutes it takes to drive away on a cold engine, it’s not worth it.

here’s one