I'd also heat the intake manifold. My dual one-barrel Rochesters had the same hesitation until I heated the intake manifold (this was a 261 - note the comment above, regarding a 235). There is a cooling affect (latent heat of evaporation) that takes place when the fuel is vaporized. The vaporized fuel then cools and condenses. That is why the stock intake manifold was bolted to the exhaust manifold.
What style of exhaust manifold do you have? If you have the stock exhaust manifold attached to the Fenton intake, you're OK.
