I recently posted a question about increasing the size of my heads to add hp. I have windsor jr (ported) on a 347. I have been talking to a local machine guy who says that rather than spending money on heads, just increase the jet size on my carb. He says that a stock out of the box carb (in my case a holley 770 street avenger) is set to run too lean, by increasing jet size by 2 you can add between 30 and 50 hp..He then said - "noone will tell you that this actually works cause its a trade secret."..so im a dumb--s and dont know what to believe so can anyone confirm this theory? I always thought lean meant mean but he is saying with my set up especially it will add more than changing out heads. Again my appologies for being a dummy cause im sorta new to this whole speed stuff and I'm trying to learn. Thanks for any help u can give

 

I think that guy is pulling your chain.
Your best bet would be to take the car to a chasis dyno and have it tuned.

Jim

 

I'd vote for a tune also

 

thats what i thought thanks guys for the feedback

 

You're not going to pick up 50hp by changing 2 jet sizes unless it's on a huge high rpm racing engine.

Better heads, custom cam and tune it.