Cam choice

['73red-duster]

OK guys,my 340 is at the machine shop. Need help picking out a cam,and tc. '73 Dart Sport,727 auto,currently .321,but probably going to .355 rear. Square decking the block,and milling the heads,to achieve about 9.5-1. J heads,with 2.02 valves. 650 Holley,stock iron intake,headers,with flowmasters. Running 255-60 15's on back. Probably never see the strip. Just a nice cruisin car. Did I miss anything? What do you think?

 

[340srule]

I've had great success with the Lunati voodoo series of cams,for your engine i'd recommend the.454/.475 cam....

 

[dgc333]

I have the Comp XE268H in my car and it runs extermely well. The Xtreme Energy series of cams is very similar to the Lunati Voodoo. They are fast ramp designs. They will give you more low rpm vacuum but still run well on the top end. A cam in the 260-270 advertised duration range from these lines would be a good choice.

 

[ValiantMike]

I'm not sure if you know this or not, but if you go to Competition Cams website, there is an area that you can load up your car and engine specs, and in a few days they will email you their cam recommendation. Mike

 

['73red-duster]

Thanks Mike. Went there,and did that.

 

[pagilman]

Hi, can I ask what year engine you have and are the pistons stock? I am new at this, but I thought all 340's excluding 1973 the last year, had at least 10 to 1 comp from the factory. I have a 71 that was positive decked at .026 and with stock x heads and I am expecting 10.5 to 1. Are the x chambers smaller than the j's Am i wrong? thanks walt

 

['73red-duster]

This engine is a '72. First year for lo comp motors. 8.5-1,same in '73. The book shows 10.5-1 for '68 through '70. 10.3-1 for '71. I believe chambers are the same.

 

[moper]

You also want to be wary of published reality, and reality. They are not the same. No 340 that came off a production line ever got to 10.5:1 when the true ratio was measured and figured. That would be why machine shops "blueprint" engines. The factory never got things that good...lol.

 

[rumblefish360]

He he he, that's true.

If your picking a cam yourself, do so with alittle info given by the cam companys themselfs. Pick the cam in a duration that is in the cruise range of your ride. If it is a heavy ride. error on the small side.

To help us help you, be sure of a few things. Your gear ratio is very important.

DGC has a good suggestion on a cam. 340's rule's cam is also right in there as well. That's about where you want to be.+ or - a a few degrees is nothing.