Looking for more zip to my /6 need a little help

[72duster12]

I sent this as an email to Clifford a few days ago, no word yet, to see what they say. I would also like to hear what all you have to say about it.. I was really just trying to build on the top end without going into the motor. I just got all my bushings replaced, new leaf springs and about to get a set of 205/75/R14 tires, thanks for the help guys-

Hi,
I have received a printout on my slant six motor from you with recommended performance enhancements. I have a 1972 Plymouth duster with a 225 all internals of the motor are stock. I am interested in doing the head, machine, and cam but I have a few questions before I get going so I can get an idea on cost and mechanical issues.
The only current additions that I have on the car are a Clifford 4bbl Intake, a holly 390cfm, Clifford shorts duel exhaust, and electronic ignition.
1st, I noticed that you recommended a 260M or 264H. Would there be a problem if I used either of these cams listed below and what would be the benefits of them?
Chrysler 225 ci, 6cyl. 1960-87

Application/
CamshaftsRPM
Oper.
RangeCamshaft
Part #DurationValve Lift
w/1.5 rockerLobe
Sep.
Angleadvertised@ .050"IN.EX.IN.EX.IN.EX.High Energy - Hydraulic Flat Tappet Great power in mid range RPM. Good choice for trucks and tow vehicles. Smooth idle.1200
to
500064-247-4260260212212.440.440110°High Energy - Solid Mechanical Flat Tappet Excellent choice for trucks and towing. Good power in low-mid RPM's. Smooth idle.1200
to
500064-241-4264264220220.440.440110°​

2nd, if I used a set of pure EV-8 grade stainless steel, head sizes of 1.70" and 1.44", would I need to notch the pistons if I milled the .080 off the head as suggested OR would I get better performance from the stock valves if they were given a 3 angle job?
Also, How much could I mill off the head before I have to worry about clearance?

3rd, could you give me a ballpark figure on sending the head in and having these services done? (The milling and resizing on the valves along with installing them)

The car is a great daily driver but I would love to have a little more zip out the motor without getting too expensive or really into the motor. Any additional recommendations for this application would be appreciated. Thank you

 

[slantsixdan]

Be very careful before you decide to spend any money with Clifford. They have a long and ugly reputation for being a bunch of clowns; see for example here, here, here, here, and here. Much of what they sell is inaccurately described, and a lot of it is not even slightly cost-effective. The good news is that you don't need to go to Clifford to get hot rod parts for slant-6s; there are lots of other, better options. See for example Dutra Duals and header options discussed in this thread and this one, Erson custom cams, HEI ignition upgrade, 1.6-ratio rocker setup from RAS, Mike Jeffreys windage trays, Hurricane intakes, other exotic intakes. Hi-perf engine buildup here, high-perf parts and build info here.