Upgrading my 340

Your at a crossroads performance wise.
Transforming an A Body into a 13 second car is pretty easy and make for a fun and very daily driver kind of car. But after this every performance gain cost more per hp and cost in the drivablity department.

It seems like your looking for something to buy that will gain you a huge improvement in power beside nos everything is 5-10 hp improvements carb, headers, intake etc...

The only thing that's left to give huge power that doesn't require a complete redesign of your engine would be fully ported heads.

But before I'd buy anything. I'd start a new thread in the racing forum and dial in what you have before trying to move to the next step.

P.S. What tires do you run at the track ??
Good info; all that helps. Find out the pistons that you have so we can get a complete idea of the guts in the engine. If it was a top end change out on a stock engine, or if the bottom end was rebuilt to stock specs, then just let us know that.

I am suspecting that with the heads, assuming they are the Small Block Edelbrock clones, then the pistons in your engine are not stock replacements. And I assume you mean 1.60" on the exhaust valve, not 1.9"....

Head gasket brand and part number would be good to know too.
I runon my street tires...BF Goodrich 245 R 14's I believe I had them down to 22lbs for traction. I thought my exhaust valves were 1.9's . Aren't the 340-X heads 1.9's with 2.02 intakes?