big block cyl head question.

[wyrmrider]

I screwed up on the overlap calc-- it's not that bad
The top whiplash should be 5 degrees overlap @.050 compared to -6 for the smaller but more conventional grind

 

[wyrmrider]

The Summit 6400 and 6401 are the same as the Edelbrock performer and performer plus and available from most all the builders suppliers like Elgin, Sealed Power etc
at least 50 years old, they wear well are designed to be inexpensive and have few warranty problems. the manufacturing quality is excellent
now the 6401 shows seat duration by the SAE method- .006 at the valve or with 1.5 rocker .004 a the cam (Same method as Crane, Sealed Power, Wolverine etc)
298 SAE intake duration 303 SAE exhaust this is a really lazy lobe, even lazier than the factory Magnum
This would be similar to a 290 Comp note that it passes the .050 closing point 5 degrees later than the Hughes example-41 ABDC compared to 36
the .006 and .004 points have to be much later
you are loosing a lot of compression distance, you want to get the valve closed to build compression 5 degrees is a lot but the real closing point is much worse
note the Summit info says
Requires 9.5:1 and higher compression,
so what to do
get the real compression and pick when you want the intake to close
as the intake is closing the charge as mass and velocity which is slowing down as the piston starts to come up
you try and close the intake to increase (or maintain) the velocity past the valve and when velocity final gets slow you finish shutting the valve
so head flows are important
and the phenomena is rpm dependent

 

[1967coronet]

I will not be running to big of a cam. I want to end up with a smooth running engine that has some guts down in the lower rpm range. My old 383 has always been dependable but its time is near up

The Summit 6400 and 6401 are the same as the Edelbrock performer and performer plus and available from most all the builders suppliers like Elgin, Sealed Power etc
at least 50 years old, they wear well are designed to be inexpensive and have few warranty problems. the manufacturing quality is excellent
now the 6401 shows seat duration by the SAE method- .006 at the valve or with 1.5 rocker .004 a the cam (Same method as Crane, Sealed Power, Wolverine etc)
298 SAE intake duration 303 SAE exhaust this is a really lazy lobe, even lazier than the factory Magnum
This would be similar to a 290 Comp note that it passes the .050 closing point 5 degrees later than the Hughes example-41 ABDC compared to 36
the .006 and .004 points have to be much later
you are loosing a lot of compression distance, you want to get the valve closed to build compression 5 degrees is a lot but the real closing point is much worse
note the Summit info says
Requires 9.5:1 and higher compression,
so what to do
get the real compression and pick when you want the intake to close
as the intake is closing the charge as mass and velocity which is slowing down as the piston starts to come up
you try and close the intake to increase (or maintain) the velocity past the valve and when velocity final gets slow you finish shutting the valve
so head flows are important
and the phenomena is rpm dependent

Thanks for that info, I will measure the piston to deck but will have to go with the factory 88 cc measurement for the 452s, I figure it will come out low 7. 5.1 or even 7.1, I am not doing any surface work on the deck or heads except a clean up so I will have to use a decent sealing head gasket not a shim style. I have emailed Howards Cams and gave them numbers of the 440 at 7. 5.1, alum dual plane , headers, 750 cfm carb, plus gear ratio, weight of car , tire dia , stall ect stll waiting to hear back with their recommendation, I told I just wished to bump the torque as much as possible along with whatever HP there is to be had.
I understand cam selection will make or break this deal , I for sure do not want to over cam it.

 

[wyrmrider]

Howards is as good a place to start as any
go to https://howardscams.com/rt-4932-downloads.html
and download the lobe list
then find the .904 MOPAR Hydraulic list
what they suggest SHOULD BE ON THAT LIST
but with most camgrinders it is easier to sell something off the chevy list
so double check- no one else will do it for you but post up their suggestions

 

[wyrmrider]

88 cc is the blueprint minimum
more like 96 out of the box
anyone else have any experience with stock 452's?
it's been awhile

 

[1967coronet]

Howards is as good a place to start as any
go to https://howardscams.com/rt-4932-downloads.html
and download the lobe list
then find the .904 MOPAR Hydraulic list
what they suggest SHOULD BE ON THAT LIST
but with most camgrinders it is easier to sell something off the chevy list
so double check- no one else will do it for you but post up their suggestions

Still waiting to hear back from Howards, Just for fun I went to comps sight and used their online engine / car spec sheet and online dyno
The guy I bought the 440 from has a cam & lifters from comp he asked if I wanted to buy.
I didn't at the time since I knew nothing about the specs.
I ran it on their sight its the 268AH 10 part number 21 305 4, at my 7. 5 .1 comp {Guess} stock heads and dual plane and 750 carb & headers it comes in at 317hp 449tq it runs the tq. curve over 400lbs from 1,800 to aprox 3,800 rpm.
It appears to be the step up from the 383 / 440 mag mopar grind according to comp.
comps #21 222 4 is 3hp less but 13lbs more tq but a little shorter tq curve.
So I will wait to hear from howards and see what they have.

 

[wyrmrider]

you do not want a 268AH basically a Magnum cam and an old design

where did you get the comp torque numbers
looking at the Howards catalog for catalog on the shelf grinds they appear to be "universal" ie chevy grinds
so two ways to check if you are being asked to leave performance on the table
see if they use the same duration and lift for a small block chevy- or even the same grind number
and
check the durations and lift against the .904 master list I posted above
IMHO 268-270 may bee too much seat duration for a low compression motor (unless you rev the snot out of it)

 

[wyrmrider]

1.6 1.5 lobe .006 .050 200
506 .475 .316 252@ 206 126
HM2063164A

XE262H 462/470 262.264 218/224 21-222-4 extreme energy
268AH-10 .495 .464 .309 268@ 222 MAGNUM CAM comp-is 21-305-4 Magnum muscle
.531 498 .322 263@ 216 136 HM2163318A Howard
.515 .483 .322 257@ 210 130 HM2103219A

you can compare comp advertised with Howard directly as they both use .006
.050 is the same
you see you can use a much shorter Howard and get more much lift
Comp also has .904 lifter profiles but non of those are except the Magnum which is weak

 

[wyrmrider]

http://www.kmart.com/competition-cams-21-305-4-magnum-muscle/p-SPM14809347424
In all fairness Comp increased the duration at 50 (Factory is around 114) with the stock magnum seat timings thus increasing the area under the curve- lift is about stock
here are some other versions of the Dodge Magnum Cam you can see the Crane is a blueprint
Crane 447/464 272/292 214/226 115lca -5 39 51 -5 @.050

Lunati .455 .303 278.288 216/226 Lunati Magnum 112

268AH-10 .495 .464 .309 268@ 222 MAGNUM CAM comp

547 560 513 525 342 350 222/226 110 4 38 46 0 +4 overlap Hughes SEH2226BL 6 pack and Mag ex Hughes squeezes the LCA
SUM 6401 466/488 298/303 224/324 114lca 3 41 56 2 54 overlap @.004 “Requires 9.5:1 and higher compression, “

remember none of these are designed for low compression, lift is kept near stock
intake exhaust
crane 214 226
crane -5 39 51 -5 -10 overlap 115lca
Hughes 222 226
Hughes 4 38 46 0 +4 overlap 110lca
summit 224 234
Summit 3 41 56 2 +5 overlap 114lca
so what works for You in your build 8 degrees more intake with 14 degrees more overlap with intake closing about the same place or????
Intake closing later?
High lift version from Hughes (.518/530 lift)
Hughes 224 228
Hughes 5 39 49 -1 +4 overlap 111lsa HUG SEH2428BL-11
or build your own
Howard 224 518 lift 272 duration now pick an exhaust lobe and lca

 

[1967coronet]

Well never did hear back from Howards, I did order a cam kit from Jegs the comp cams
21 - 215 - 4, lift 454/454 dur 218/218 at50% Ls 110, with lifters and chain & gears. add said it was good for lower compression B and RB application.
also ordered the felpro rebuild gasket set. I will use my local napa for a new oil pump & valley pan, I have the headers,750 eddy and pertronix for the distributor & coil.
bottom end is cleaned up, soon as the felpro set shows I will have my valve seals and will do a light lap job & clean up ck guides & stems and install the seals if all looks ok.
Still have to locate a aluminum dual plane , may end up with a new one ?
Depending on that I will be between $1000 and $1250.00 plus what parts I already had around.

I will get a new Lic plate that says Cheapaz if this thing works out LOL.
Thanks again guys for the replies and help.

 

[wyrmrider]

what lunati says about that old chevy grind a Magnum replacement not exactly the RV type you mentioned early on
10210207 06307 1200 - 5200 .457"/.457" 218/218 268/268 110 Hyd/Hyd Works well in 383-440 c.i. motors for daily high performance street usage. Needs increased compression ratio. Good idle. Lunati says at least 9:1
compare that cam with the Lunati Voodoo- also from Jegs voodoo has the same lift with 15 degrees less seat timing

The 268 High Energy closes the intake 60 degrees ABDC
the Voodoo closes the intake 54 degrees ABDC both at .006
(comp 256H also closes at 54)
it's like advancing your cam 6 degrees- tell me it does not make a difference
you want to save some money just use the stock non HP 440 cam and advance it 4 degrees

 

[1967coronet]

I just went back and checked, Summit had it in their add that it was a decent match for 8.1 to 9.1 compression so I figured it was a pretty good match to what I would need.
I ended up getting it from jegs, I spilt my order of parts between the two.

I hope I am not overboard at those specs , I didn't want to get to big on lift and duration.
If I am to light on compression and can switch to the 516 heads I have on the 383.
I will just have to try it out and see what it feels like.
Comp claimed a pretty smooth idle and that's also what I want.
Thanks