340 Cam Comparison

gzig5 said
That's interesting because I got a recommendation from Mike Jones that has even more duration 244/252, .365/.364" lift, @108 center for pretty close to the same potential combination. I will be first to admit that I don't fully understand how the different parameters affect performance and drive-ability, so I am trying to learn. I'm willing to try a couple combos to dial it in but hope to start in the general ballpark. For this interim motor though, you may be correct in less being more. But looking for feedback from someone that's run this or similar cam as to how it behaves. Hate to "leave too much on the table".

the reason I suggested stepping back in duration is you stated decent street manners.
Mopar small block heads are not known for good flow numbers, push rod gets in the way of the intake port and the bolt boss get in the way of the exhaust port(only somewhat cause some of the best gains from porting an exhaust port come from the roof being modified and raised, hot air rises.). the reason you want less LSA is to help pull in a fresh charge of gas and air by pulling it in when the exhaust gets sucked out. less LSA= more overlap which the intake valve is open while the exhaust valve is open. this helps make up for a less than desirable flowing intake/exhaust ports. the increased the duration of the exhaust lobe of a dual pattern cam helps this as well. and yes all this will cost you some horsepower and compression as more LSA is less overlap and more compression. as for the 1 5/8 headers, they help with increased velocity and match the flow better in a less than desirable flowing head. cams and headers have to match the capabilities of your head. all out racing cams and heads work well with those bigger headers but run like crap on the street. just watch a stock class mopar drive thru the pits at an NHRA race with a 320 duration cheater cam. you would be cussing at every stop sign/stop light.

back in the day(1977) I ran a stock 340 dart with Direct Connections Street Hemi Grind camshaft. .471/.474 lift, 284 duration and 90 degrees overlap(smallish LSA). I'm guessing it was about 227 duration at .050 lift. It was designed to be used with stock stamped rocker arms and stock cast iron exhaust manifolds which I know you are not planning to use. It idled a bit rough but smoothed out soon after idle, had plenty of low end torque, pulled hard once it came into operating band and raised the upper rpm limit quite a bit. it was a blast to drive. alot of guys I have talked to are real happy with Hughes Engines cams they have and on FABO I hear alot of good things about Oregon Cam grinders, more modern lobes and cam profiles they both use.

don't worry about the shivvvy and furd dudes, you wont have any problems putting the smack down on them, I didn't. you will even look good up against the new modern muscle cars as well. dudes on Street Outlaws are always talking about too much horsepower and over powering the street. 700 horsepower is a lot of tire smoke on the street but real nice on a glued track.