How much cam can I get away with using the stock heads and pistons in my 1980 400. I am looking at budget build for now, headers, intake, carb, timing set, cam & springs-as needed, dual exhaust w/ 50 series Flowmasters. 2wd dually that will be used for hauling as needed and possibly camping trailer someday. I prefer lopy/choppy idle. I've used Comp Cams previously. How does their quality compare to other brands these days? I am thinking of using a Weiand intake kit from Summit and Hooker Headers 6914HKR. I wasn't planning on pulling heads.

 

More truck info - C6, 4.10 gear, limited slip, 235/85R16 tires-included this because they are a bit taller than the stock size that I just took off.

 

With the low compression, you need a short duration, high lift cam. That is oversimplified, but the cam people know the stock 400 and you can find cam that will improve power by filling the cylinders without allowing overlap or reversion.

Lumpy cam and low compression could give you a real pooch with a narrow power band. I wouldn't even do headers at that level. It's not like the 400 has those flat against the head jobs like the FE.

Serving suggestion, ymmv

 

As the previous poster said low compression and lumpy cam don't mix well especially in a dually used for hauling/towing when you need good torque. The combination just doesn't build good cylinder pressure. A cam similar to Comps 255deh would work well. Won't be lumpy but will work with low compression. A lot of people will suggest the XE256 or the XE262 but I believe comps XE line might be to aggressive to get any longevity out of.

 

235/85R16
basically is a 31.7 inch x 9.3 inch x 16

 

Comp's 268H will do you nicely. Those tires won't hurt you either. That's the stock size came with my 99 SD F250 with 3.73's. They'll help a bit on the highway with those 4.10's and the C6

 

Do not forget to remove the exaust valve rotators on the stock heads if you put a cam in i They cause coil bind and will break pushrods only, if you are lucky. Can cause valve to hit piston possibly. How do I know ? Brothers 79 400 had a crane blazer cam, with stock heads (500 lift as I recall). Ford mechanic did not notice and left rotators on exaust springs. Broke and bend pushrods (coil bind) and bent exaust valve head, luck it did not break off. Took rotators off and shimed under pedestals. Was a real HOSS !!