What cam to use in a 318

furz4 said
I have the Hughes springs and retainers on the magnum heads with .510 lift the seals just clear so I wanted to stay a little less then that, that's why I was thinking around .500 max . My current 318 runs a factory 340 automatic cam which is 210 & 220 @.050 runs good but I doubt the compression is even 8:1 and lift is only .421 .444 I believe. I had thought of running that in this motor with the 1.6 rockers but I think there are better choices then 114 center line, I think 110 would probably work better. Something like the comp 20-417-3 perhaps, although I am not sure a dual pattern cam will make much difference on a street car but they are widely used when running full exhaust.

The extra exhaust duration helps get more exhaust gases out and will add a few more rpm to a single patterned camshaft. Headers or not.

Garrett Ellison said
I like this cam for that combinbation. 108 LSA & 104 ICL DODGE Howards Cams 710991-08 Howards Cams Hydraulic Flat Tappet Camshafts | Summit Racing

I running this one in my 5.9 with the trick Hughes springs and retainers.
(727/2500 stall, 3.55 gears.)

Dan the man said
Does any camshaft company offer a exact reproduction 340 cam? I've found a few that the advertised duration is correct but the duration at 0.050 is more, the lift is never correct either. The 340's were discontinued 51 years ago and I don't know if the patent rights are still in effect.

Mellings makes OEM repops.
Patents expire after a few years. There is a discussion on in the W5 copy thread. There is also a link in there on patents.