Rebuild Question

[David]

I am looking at rebuilding my 318 and would possibly like to follow this build plan http://www.moparmusclemagazine.com/techarticles/mopp_0409_318_engine_build/machining_process.html. I have a couple of questions concerning this build. The magnum heads they are referring to are those the ones that are found on the 5.9l engines? Would the headers I have on my 318 heads still bolt up to the new magnum heads? Would this cam " Competition Cams 280H Magnum camshaft, which is a single-pattern grind featuring 280 degrees of rated duration and 230 degrees of duration at .050-inch tappet rise. This cam is advertised as having .480-inch lift" work with the stock vavletrain of the magnum heads? Also it requires a 750cfm carb, is there any particular brand or model you guys would recommend? Thanks for any input and help.

 

[Meep-Meep]

I don't know about what heads these are but you will need heavier springs to go with that cam and likewise should use 3/8" high strength push rods. You might have to correct the retainer to guide clearance as well. I'm not familiar with how reliable the late Magnum rockers are so you might want to look into how they will handle the extra spring load. A 280 deg cam with 10:1 CR and a closed chamber head should be just dandy! Oh yeah, I don't think the traditional LA headers will work, but I'm sure someone here knows that answer.

 

[David]

Thanks for the help. As far as pushrods they used Comp Cam's number 7960 pushrods at 7.650-inch length THis is what they said about retainer to guide clearance "The retainer in a stock Magnum head will physically hit the valve stem seal at .530-inch of lift, thus putting a ceiling on cam selection." So with the higher 1.6:1 ratio of the Magnum engine they used the 280 degree cam because they didn't want custom mods. They said the magnum rockers had excellent rockers but I will probably end up going aftermarket for those because I found a set of magnum heads off of a 360 crate motor that has upgraded springs but no rockers.

 

[David]

Anyone have any more input it would be appreciated....