what cam for 340 bored 0.30 over?
Yur gonna have to more specific.
And yur gonna have to make a decision on automatic OR stick, the optimum builds are different.
And the "2.96" gears are the first thing that has to go.
The reason being that a 5500 rpm shift rpm, will get you about 60 mph at the top of first. That sounds pretty good, but you got no passing gear. So when you pull out to pass somebody doing 58mph, on the downshift,your rpm will jump to 3560 in second , or to 6000 in first, neither of which is any good to pull from. On the other hand 65=2390@zero-slip, in Drive, so that's nice.
a 5500 shift is about a 5100 rpm power peak which is about a 224@ .050 cam, which is like a 268advertized cam, like a 340 was born with..
So you gotta decide if yur keepin' the 2.96s or not, cuz the engine build is gonna be completely different for about every 10 to 15% gear change.
And the next thing to be assessed is the 2500 stall. If you put a 2500 on the 2.96 gears, yur gonna need a hi-torque 360 to get moving. After 20/25 mph it will be fine, but getting there will be frustrating.
So if you are ready to throw out the 2.96s and the 2500, then the next question is this;.
Hiway or city? a 340 with a TorqueFlite, can barely do both in the same combo, so you are gonna have to prioritize one or the other. So if hiway, spit out a number that you are willing to cruize no higher than. From that we can back-calculate a gear ratio, and a possible stall.
Then we can start on the engine.
If you build the engine first, without regard to these things, then you are setting yourself up for disappointment.
And here's why;
With a TF, no matter what street rear-gear you run, you will never get into third gear below the speed limit. For example; top of second even with 3.91s is about 5000@65mph. If you are cammed for that, that is the best she is gonna do. Very few guys run more than 3.91s on the street because in drive, 65 is 3160@zero-slip with 27" tires; could be 100 to 150 higher depending on the terrain.
The point is; there is no good reason to run a 7000rpm engine in such a combo, cuz the only way to see 7000 is if the tires are spinning, or if yur speeding. Spinning ain't winning.
Furthermore;
A bigger cam always moves the operating rpm up; this is immutable, because of the way it is designed. If the heads support it, the higher rpm will make more horsepower. But generally, the cam will steal some of that rpm off the bottom. So the engine gets hi-rpm power by trading away lo-rpm power.
Riddle me this; how is this a good thing for a streeter?
It isn't.
And so, to overcome that loss of low-rpm power, you have to install a higher rpm stall-speed TC, so your engine is never forced to pull in that dead-zone.
OK so now you got both ends covered..... right?
What about passing gear? At 58mph, as before, your kickdown-rpm into second will be about 4500, and 5000 will be 64mph and 5500 will be 71, so if you are OK with ripping past grandpa with the engine screaming, this might be ok, except for one thing; 71mph will be 3450@zero slip, probably closer to 3600 at WOT, relaxing to 3550 to cruise with. That is way to high for me to cruise at. Relaxing to 65 mph will get you about 3250.Still too much IMO for an A-body. It could take a few tricks to make this not tiring, on anything but short hops..
So this sorta gets complcated.
Way beyond a simple answer with only this to go on;
hi guys what cam would yall suggest for a 340 bored 30 over with trw pistons? and should i use my stock x heads and intake?
