Just a question
 

Without knowing the change in timing from the cam, and what they recommend, usually you should be putting new springs in so the rods stay in contact with the cam and/or not wear down the cam with excessive pressure through the rod. Just some advice given to me when I put a new cam in my 440.

Well, thats the thing, if I'm going to stay w/ the J-heads, I was going to have new springs put in, obviously bigger cam = new springs. But I just want to know if the shaved X-heads are worth re-doing and putting on.

In ref to your earlier post, I'd bet that if you worked over the distributor, or put in a better one, and worked the advance and timing over, that you would be in the 13's with what you have.

That's assuming that everything else is in good shape enginewise, and maybe do some carb tuning as well.

Here's what I'd do

Tune what you have, IE reworking the ignition and carb for best results

If you're not happy, put in the better cam. Stock 340 heads just aren't that bad. Stock heads, and maybe a lower gear should get you into the 12's with that new cam

Last thing I'd do is swap heads

I'll take that into consideration. Thing is, I'm not good at Distributors. And a new one cost a bit for me. So i'll take what I have. :)
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And what do you mean by "lower gears"? As in go from a 3:55 to a 3:23, or to 4:10? To add to that... I want this car to be STREET. It's a street car, not a race car. Sure, you can drive 12 second cars on the road, just not for a long time. I like my slug of a Dart. And I don't want to be running 12's yet. I've only been to 4 actual races, and 3 test n tunes so far, as I got my license in August.

Faster then 13 seconds = Pro. (And no, I will not sand bag..)