440 cam

[robs 67plymouth]

im building my plymouth for a weekend cruiser i want to put a cam in, what size can i go without changing springs. doing valve job and new timing gears and chain and new gaskets. it has 452 heads with green springs. its a 1974 pretty much stock will be using double plane and 650 carter afb

 

[Mrmopartech]

You are limited by the coil bind and clearance of the valve spring retainer and the seals/guides.You need to have a dial indicator put on the head and see when the spring stops,then remove 0.075-0.100 off of that spec,this spec allows for heat expansion and clearance.But this is not the way to go about this.You need a cam kit,with proper srings and retainers and locks,plus you will need adjustable rockers and push rods.The new cam installed with out the kitmost likely will never start due to it keeping the valves open all the time,due to no adjustability,mrmopartech

 

[moper]

That's a truck/motorhome engine, right? You should replace the stuff mentioned, and I'd run the street hemi type springs and the Summit brand small cam kit.

 

[Babyblue66]

If you are not replacing the springs or any more parts, just a stock replacement.

 

[robs 67plymouth]

thanks for the info

 

[moper]

The valve rotators on the exh valves severely limit your lift. Those springs are very, very weak.