: I am thinking of building a head for my 6 and
: went through the archives on valves. There
: is so much info and recomendations I am now
: more confused than when I started.
:
: Currently I have a stock head that has been
: surfaced 0.60", an Offy 4bbl manifold,
: 390cfm vacuum secondary 4bbl, COMP 252S cam
: and 6 into 2 headers with dual exhaust (3:23
: rear with A833OD). This combo runs very
: wheel but no one will ever mistake the car
: for fast. Currently the power is all over at
: about 4k rpm. I have been told that new
: valve springs will extend out the power band
: and I hope to install the COMP Cam 970-12
: springs I have sitting on the shelf this
: weekend.
:
: My Barracuda is a driver and I love the
: attention it gets with the 6 set up. I
: would like to keep the 6 and increase the
: power to make the car low to mid 15 sec
: capable like my Shelby Daytona.
:
: Here is my list of questions;
:
: 1. I looked through a valve catalog and no one
: has a 3/8 valve that is the same length as a
: 6 valve. The closest was AMC 258 valves (I
: 1.787 E 1.406). These are less than .1"
: longer. What is the maximum the valve can be
: longer than stock before you need to do
: something about the valve train geometry?
: 318 valves seem like a good size (1.78/1.5)
: have the 3/8 stems but are almost .2"
: longer.
:
: 2. Is the AMC 1.406 Ex. size even worth
: considering since most of the recomendations
: are a 1.5"?
:
: 3. Are the MP oversize 6 valves still around?
:
: 4. What are people spending to have valve seats
: cut for bigger valves?
:
: 5. What are people spending to have valves
: shortened?
:
: 6. Are there any porting templates around for
: the 6?
:
: 7. How much improvement in power could I expect
: by just having a good 3 angle valve, job
: blend the seats to the bowls, clean up the
: ports and gasket match?
:
: If doing up a head to support the power I am
: looking for is going to approach $1k then I
: will likely look at a 360 v8 swape again.
:
: Thanks!

: My Opinion "please treat it as such!"
: ditch the comp cam! i had the 264s and
: quickly replaced it with the 264 (228*at
: .050) .448" isky. the isky is a HOT
: little cam with very good street manners.
: Do a good clean up and gasket match on the
: head. good valve job, and a new set of 340
: springs. don't wast the money on the comp
: blah blah whatever springs. they are most
: likely made by melling and put in a comp
: box.
: you may need a touch more compression than
: -.060 from the head can yield. maybee -
: another.100 from the deck!
: more carb than the 390, try the 500 edelwebber.
: msd or crane ignition
: 904 tranny tweaked with moderate convertor.
: i have run 16.6 at 84.88 mph in the 1/4 with a
: 3600 lb aspen with 3.21 gears with a similar
: setup.
: start with a GOOD cam and a fresh head.
: (racesearch.com sells the isky!) you are
: running out of cam at 4,000 rite now. the
: 252s is at best a stock replacement, not
: even worthy of the RV cam tag. once again,
: only my opinion.

: I am thinking of building a head for my 6 and
: went through the archives on valves. There
: is so much info and recomendations I am now
: more confused than when I started.
:
: Currently I have a stock head that has been
: surfaced 0.60", an Offy 4bbl manifold,
: 390cfm vacuum secondary 4bbl, COMP 252S cam
: and 6 into 2 headers with dual exhaust (3:23
: rear with A833OD). This combo runs very
: wheel but no one will ever mistake the car
: for fast. Currently the power is all over at
: about 4k rpm. I have been told that new
: valve springs will extend out the power band
: and I hope to install the COMP Cam 970-12
: springs I have sitting on the shelf this
: weekend.
:
: My Barracuda is a driver and I love the
: attention it gets with the 6 set up. I
: would like to keep the 6 and increase the
: power to make the car low to mid 15 sec
: capable like my Shelby Daytona.
:
: Here is my list of questions;
:
: 1. I looked through a valve catalog and no one
: has a 3/8 valve that is the same length as a
: 6 valve. The closest was AMC 258 valves (I
: 1.787 E 1.406). These are less than .1"
: longer. What is the maximum the valve can be
: longer than stock before you need to do
: something about the valve train geometry?
: 318 valves seem like a good size (1.78/1.5)
: have the 3/8 stems but are almost .2"
: longer.
:
: 2. Is the AMC 1.406 Ex. size even worth
: considering since most of the recomendations
: are a 1.5"?
:
: 3. Are the MP oversize 6 valves still around?
:
: 4. What are people spending to have valve seats
: cut for bigger valves?
:
: 5. What are people spending to have valves
: shortened?
:
: 6. Are there any porting templates around for
: the 6?
:
: 7. How much improvement in power could I expect
: by just having a good 3 angle valve, job
: blend the seats to the bowls, clean up the
: ports and gasket match?
:
: If doing up a head to support the power I am
: looking for is going to approach $1k then I
: will likely look at a 360 v8 swape again.
:
: Thanks!

:
: Thanks for the feed back. But I do have a few
: questions regarding your response.
:
: 1. What is it about the Isky Cam that makes it
: that much superior to the Comp Cam when both
: have pretty much the same specs?
:
: 2. Erson has a 270/270(220/220 @.050), .465
: lift, 111 lobe center, 4 adv. Do you have
: any comments on this cam?
:
: 2. What is wrong with Comp Cam valve springs?
: Or, Melling for that matter? (BTW I got the
: set of COMP cam springs for $20.00)
:
: 3. A total of .160 removed from the head and
: block seems excessive. What kind of
: compression does that create?
:
: 4. I have not run my Barracuda but it' quite a
: bit slower than my Shelby Daytona (best of
: 15.2) and a bit faster than my wifes Avenger
: (best of 17.0). 16.6 seems like it's in the
: range of what the car will do now with the
: current mods. Is low/mid 15's resonable with
: just some head work? The bottom end is sound
: and I have no plans to pull it.
:
: Thanks

:
: I am thinking of building a head for my 6 and
: went through the archives on valves. There
: is so much info and recomendations I am now
: more confused than when I started.
:
: Currently I have a stock head that has been
: surfaced 0.60", an Offy 4bbl manifold,
: 390cfm vacuum secondary 4bbl, COMP 252S cam
: and 6 into 2 headers with dual exhaust (3:23
: rear with A833OD). This combo runs very
: wheel but no one will ever mistake the car
: for fast. Currently the power is all over at
: about 4k rpm. I have been told that new
: valve springs will extend out the power band
: and I hope to install the COMP Cam 970-12
: springs I have sitting on the shelf this
: weekend.
:
: My Barracuda is a driver and I love the
: attention it gets with the 6 set up. I
: would like to keep the 6 and increase the
: power to make the car low to mid 15 sec
: capable like my Shelby Daytona.
:
: Here is my list of questions;
:
: 1. I looked through a valve catalog and no one
: has a 3/8 valve that is the same length as a
: 6 valve. The closest was AMC 258 valves (I
: 1.787 E 1.406). These are less than .1"
: longer. What is the maximum the valve can be
: longer than stock before you need to do
: something about the valve train geometry?
: 318 valves seem like a good size (1.78/1.5)
: have the 3/8 stems but are almost .2"
: longer.
:
: 2. Is the AMC 1.406 Ex. size even worth
: considering since most of the recomendations
: are a 1.5"?
:
: 3. Are the MP oversize 6 valves still around?
:
: 4. What are people spending to have valve seats
: cut for bigger valves?
:
: 5. What are people spending to have valves
: shortened?
:
: 6. Are there any porting templates around for
: the 6?
:
: 7. How much improvement in power could I expect
: by just having a good 3 angle valve, job
: blend the seats to the bowls, clean up the
: ports and gasket match?
:
: If doing up a head to support the power I am
: looking for is going to approach $1k then I
: will likely look at a 360 v8 swape again.
:
: Thanks!

: Thanks for the feed back. But I do have a few
: questions regarding your response.
:
: 1. What is it about the Isky Cam that makes it
: that much superior to the Comp Cam when both
: have pretty much the same specs?
:
: 2. Erson has a 270/270(220/220 @.050), .465
: lift, 111 lobe center, 4 adv. Do you have
: any comments on this cam?
:
: 2. What is wrong with Comp Cam valve springs?
: Or, Melling for that matter? (BTW I got the
: set of COMP cam springs for $20.00)
:
: 3. A total of .160 removed from the head and
: block seems excessive. What kind of
: compression does that create?
:
: 4. I have not run my Barracuda but it' quite a
: bit slower than my Shelby Daytona (best of
: 15.2) and a bit faster than my wifes Avenger
: (best of 17.0). 16.6 seems like it's in the
: range of what the car will do now with the
: current mods. Is low/mid 15's resonable with
: just some head work? The bottom end is sound
: and I have no plans to pull it.
:
: Thanks

: Yes, the SL6 responds well to any headwork you
: give it. I feel that you will get noticable
: power gains with your combo if you just port
: and mill the head, keeping the stock size
: valves.
:
: Bigger valves will help, the AMC ones will do.
: Another valve I use a lot are the Big Block
: Mopar exhaust valves 1.74 and the 1.6 which
: has to be "turned-down" on a
: lathe. These valves are also .1 long but
: some of that can be "taken-up"
: when the new seat is ground-onto the
: chamber, keep it up high as poss.
:
: The key to this decision is the condition of
: your head's valve guides.
:
: If you guides are worn-out, spend the money to
: sleeve them down to the F@&d 300 stem size
: and use those. The 3.8 Buick and S.B. Chebby
: can also be used. There is more selection
: and better flow at the smaller stem size so
: do some "shopping".
: DD

: Yes, the SL6 responds well to any headwork you
: give it. I feel that you will get noticable
: power gains with your combo if you just port
: and mill the head, keeping the stock size
: valves.
:
: Bigger valves will help, the AMC ones will do.
: Another valve I use a lot are the Big Block
: Mopar exhaust valves 1.74 and the 1.6 which
: has to be "turned-down" on a
: lathe. These valves are also .1 long but
: some of that can be "taken-up"
: when the new seat is ground-onto the
: chamber, keep it up high as poss.
:
: The key to this decision is the condition of
: your head's valve guides.
:
: If you guides are worn-out, spend the money to
: sleeve them down to the F@&d 300 stem size
: and use those. The 3.8 Buick and S.B. Chebby
: can also be used. There is more selection
: and better flow at the smaller stem size so
: do some "shopping".
: DD

: Here's what I did for my big valve /6 head,
: which is now complete and waiting for me to
: assemble the engine.: I got a 1979 /6 head,
: and had it hot tanked, crack checked, and
: had the guides resized to 11/32 and the
: valve seats bored out to 1.78" and
: 1.50".
: The valves I'm using are small block Phord
: windsor intakes (1.78") and small block
: Shivvy exhausts (1.50"). Wish someone
: had mentioned the AMC 258 intakes about 4
: months ago. I'd have used those instead.
: I took the head home from the machine shop to
: do the porting. A LOT of metal had to come
: out of the bowl area to get it all to blend
: together nicely.
: When the porting was done, I took the head back
: to the machine shop, and they cut the final
: 3 angle seats, pressure tested (80 psi) the
: head, and measured and installed the valve
: springs (340 replacement with dampers) and
: checked the seat pressures and installed
: height. The exhausts have .120" of
: shims under the springs.
:
: Total cost so far? Around $750.00, plus 40-50
: hours of my porting time.
:
: Recently, I ported out a set of 051 small block
: smog heads for my '79 Aspen R/T. Took them
: for a flow test, and got 215 (same as X
: heads) on the 1.88" intakes, and 160
: (20 better than X heads) on the exhaust. I
: took along the /6 head for the shop owner to
: inspect. He thought the porting and seats
: were pretty good, and it should flow well. I
: couldn't get a flow test done because they
: didn't have a fixture to hold open the
: valves that would bolt to a /6 head. I could
: make one and take it back for a test, but
: probably won't. Costs $. I'd like to know
: the numbers, but cash is getting short
: again.
:
: The guy who did the flow test told me about how
: having good seats is very important to good
: flow numbers, especially at low lifts. The
: 051 heads I ported had the stock factory
: seats, and I only did a hand lapping
: compound job on them. He said it could've
: done much better with a good 3 angle seat
: cut. I'm guessing he knows what he's talking
: about. The shop is Tom's auto machine, also
: known as Tom Hemphill Racing Engines, in
: Clarksburg, PA. He has an MP megablock with
: B1 heads in a '69 Barracuda that runs 6.90's
: at 200 in the 1/4. You can see his name in
: the Big Dog class sometimes in the Mopar
: magazines that publish race results.
:
: The 2 different valves I have in my /6 head now
: have the valve tips at different heights,
: but since /6's have adjustable rockers I'm
: not concerned about it. In the worst case, I
: should be able to put in sone rocker shaft
: shims and be done with it.

: i have had nothing but trouble with rocker
: shims in the past. perhaps consider
: making/having made pushrods to fit. if you
: did not have the spring seats cut i would
: double check the .120 worth of shim. there
: may not be enough meat to hold the
: spring/shim in place when you wind it up
: enough to get into the 14s you are expecting
: with the 268 mp cam. dropping a valve in ol
: daddy long stroke could be real bad,
: especially since there may very well be
: enough room in the cylinder to suck up the
: whole valve. owwweeey....chad

: What kinds of problems are there with shims?
: I showed the head to both machine shops and
: asked about the spring seats with the shims.
: Only the exhaust valves have shims. The one
: who did the flow testing said it should be
: ok. I told the shop that did the work on the
: head that if it drops a valve I'll be back.
: I don't like the shims being stacked up that
: high, I may try to get some of those
: 0.050" under height locks and use those
: and take out one of the two 0.060"
: shims from under each spring that has them.
: I'll probably need custom pushrods anyway. I
: don't think the rocker adjusting screw will
: go far enough to adjust out these longer
: valves. Then there's the rocker tip to valve
: tip geometry issue, but not much can be done
: about that without rocker shaft shims.

: What kinds of problems are there with shims?
: I showed the head to both machine shops and
: asked about the spring seats with the shims.
: Only the exhaust valves have shims. The one
: who did the flow testing said it should be
: ok. I told the shop that did the work on the
: head that if it drops a valve I'll be back.
: I don't like the shims being stacked up that
: high, I may try to get some of those
: 0.050" under height locks and use those
: and take out one of the two 0.060"
: shims from under each spring that has them.
: I'll probably need custom pushrods anyway. I
: don't think the rocker adjusting screw will
: go far enough to adjust out these longer
: valves. Then there's the rocker tip to valve
: tip geometry issue, but not much can be done
: about that without rocker shaft shims.

: Tim,
:
: I've never used shims, or stock sl6 or SB
: Chrylser springs in my big-valve heads. I
: always have the spring seats cut and use the
: retainers and springs and seals that are
: used with those valves (ic. SB Shiv, etc..)
:
: If your head is not milled too much, say less
: than 0.060", then you can probably get
: by with stock pushrods. Just the valve
: length alone will not make it necessary for
: shorter pushrods, there is plenty of
: adjustment room.
:
: But, your probably fine on the valvetrain too,
: just bolt 'er on and let 'er rip.
:
: Lou

: Yes, the SL6 responds well to any headwork you
: give it. I feel that you will get noticable
: power gains with your combo if you just port
: and mill the head, keeping the stock size
: valves.
:
: Bigger valves will help, the AMC ones will do.
: Another valve I use a lot are the Big Block
: Mopar exhaust valves 1.74 and the 1.6 which
: has to be "turned-down" on a
: lathe. These valves are also .1 long but
: some of that can be "taken-up"
: when the new seat is ground-onto the
: chamber, keep it up high as poss.
:
: The key to this decision is the condition of
: your head's valve guides.
:
: If you guides are worn-out, spend the money to
: sleeve them down to the F@&d 300 stem size
: and use those. The 3.8 Buick and S.B. Chebby
: can also be used. There is more selection
: and better flow at the smaller stem size so
: do some "shopping".
: DD