Isky 256 is a Chevy cam, so are the Megacams
really lazy compared to today's cams
The Purple cams are all better than chevy type masters but still not current
for example Mike Jones 256 hyd cam has .305 lift at the cam- compare that with your Isky
now the good news is that the Isky can be installed under the shade tree and will last a long time- it's that easy
the megacams rev like crazy and work good on the top end (the 310) but you give up low end
are you thinking solid?
do me a favor and post up your head flows- don;t know go to the Stan Weiss site and find something comprable
BTW pocket porting mopar heads helps a bunch
you want rump de rump or power- poke a hole in you muffler
seriously Mopars do NOT like overlap your intake blows out your exhaust so mileage sucks- even with a cam with Magnum timing- and your exhaust runs hot (hotter)
also your center two exhaust valves overheat (the valves cool mostly on the seat not through the stems)
need your compression- you have 915 heads? they flow like 906 from 68 but have a smaller chamber
so do you have stock compression? Is this an HP motor what gears and stock converter?
THink EDM lifters if you go flat tappet hyd or solid
What springs or new?
Rockers?
So we have to know is this a stock 67 compression 440 standard or HP or has it been rebuilt- can't guess on 50 year old Iron
cheers
don't know post up your cranking compression or post it up anyway
I'm thinking with that short Isky cam your compression must have been lowered somewhere along the line or it would be pinging even on premium
In anycase picking the cam timing- open and closing points comes first
I did cam and radiator testing for Chrysler in the 70's
One size bigger than the "268" Magnum cam was real close or lost on 60 foot times (stock gears and converter) ( the non magnum cam was 260 in mopar method- YOU CANNOT COMPARE MOPAR NUMBERS WITH ANYTHING ELSE WITHOUT A CAM DOC
but you can compare Mopar numbers with other mopar numbers
That 284 was a fine cam but needs gears and converter, works with headers but likes high compression
remember it was designed back when springs were not as good as today so leaves some cam acceleration on the table