Stockish 340 upgrades, cam needed

-
Cudafever said:
Did you hear them commenting on the iron running on after they shut it off.
Click to expand...
Yup. I happen to know some road race engines that run several degrees less high rpm timing than dyno or drag race tests would indicate. A fully heat soaked engine is definately a little different animal. No one I know runs alum heads road racing these engines, but that's a function of the rules. No reason to develop something that's not allowed. I know some cars driven on road courses (non competition) have used aluminum heads. Also seen some problems. But I would not make any generalization about that because every new use, especially max effort stuff, requires development. For those not willing to put the devlopment time and money in, then go conservative.
 
LO23M8B said:
Does anybody know what Jenkins said when he looked at a small block mopar head? He said if I had to race with those heads I'd quit racing. lol
Click to expand...
Yes, he told Johnny Dianna that and Lil’ Johnny immediately took him to school afterwards. Poor Grumpy...
 
Sorry I was thinking of RAMMS tread, the other 340 but stock manifold thread
he will not be needing exhaust split with those heads and headers
let's see what the compression really turns out to be
right now i'M THINKING 9.5 4 SPEED 3.23 GEARS
9.5 this is easy
10.5 will take some work
can't really do more duration because of the gears and 4 speed
so spread the lobe centers or???
Rattler type cam is for low compression not this build I do not think it has Mopar lobes either

some comparisons with a similar seat duration Howards Mopar lobe
340 Whiplash ???? 223 550 107 LCA no idea seat duration

Thumper 279 227 .486 107 LCA IC 63 ABDC

Rattler 281 227 .480

Howards 279 256 232 152 .357 .535
No question you could build a more powerful cam without the gimicks
 
Last edited:
toolmanmike said:
Has anybody asked the wife what she wants? I know a few that can handle anything under the hood. Others might be happy cruising with a stock engine.
Click to expand...
Wyrmrider said:
Sorry I was thinking of the other stock manifold
he will not be needing exhaust split with those heads and headers
let's see what the compression really turns out to be
right now i'M THINKING 9.5 4 SPEED 3.23 GEARS
Click to expand...
I think that’s going to meet the demands of the wife pretty well. I’ve not been able to find the timing events for the .506/264 cam, but I think the 104 ICL will make it pretty torquey even with the 108 LSA.
 
With an Edelbrock .050 head 11.2 cc head gasket for a .035 piston to head and quench (reviewers say it’s a FelPro PermaTorque sealed onto an Edelbrock card), I’m coming up with 9.8:1 on the nose. This brings on another question for Wrmyrider. Any dirivability advantage to advancing the cam up to a 100 ICL or do think it’s optimal at straight up for this one?
 
Wyrmrider said:
Sorry I was thinking of RAMMS tread, the other 340 but stock manifold thread
he will not be needing exhaust split with those heads and headers
let's see what the compression really turns out to be
right now i'M THINKING 9.5 4 SPEED 3.23 GEARS
9.5 this is easy
10.5 will take some work
can't really do more duration because of the gears and 4 speed
so spread the lobe centers or???
Rattler type cam is for low compression not this build I do not think it has Mopar lobes either

some comparisons with a similar seat duration Howards Mopar lobe
340 Whiplash ???? 223 550 107 LCA no idea seat duration

Thumper 279 227 .486 107 LCA IC 63 ABDC

Rattler 281 227 .480

Howards 279 256 232 152 .357 .535
No question you could build a more powerful cam without the gimicks
Click to expand...
seems like you are disqualifying a lot of good camshafts by so-called gimick? The sound is a result of a tried-and-true grind but not so aggressive that it beats the s*** out of your valve train. You can always build a more aggressive camshaft but how much abuse are you willing to put on your valve train for an extra few horsepower. On a race oriented motor I get it. But You are approaching the limits of ahydraulic camshaft stability capabilities with the grind you are suggesting. And I hardly feel this is a high compression motor, but whatever there are other questionable statements but whatever whatever I suggest you individual do a little more research!
 
Last edited:
Garrett
I do not see a 264 506 cam in my recap which cam?
I'd leave LCA till we know compression
where did posters get 10.5? I did not see that
heck with 9:1 I might go 108 to get the intake closed earlier but would also depend on how much spread
With 10.5 I might go 114 like momma mopar did in the first place - that would cut the pressure
remember the stock 340 cam is
340 cam 279 210 .429 2899206 intake @.006
so 264 (so given that a lot of that duration is on the long slow close side going 15 degrees shorter for both sides is a bunch- pick how much earlier that 264 cam would close earlier than the 279 stocker (both at .006) I think you would have all them DCR the motor could handel at 110 or 112
Reading Aj I think 165 Compression would be a low target but some canmake 200 ish work- and that's what makes a motor feel snappy
or we could get Aj to calc all the dynamic compression variables
I'd still feel better if the heads were cc'd

KO a higher rpm high compression motor can use a longer duration lobe
none of the lobes mentioned are "fast rate"
this is a fast rate chevy lobe followed by a standard rate MOPAR lobe
..................006.020.050,200
3HF213307 260 237 213 127 0.307 Aggressive .842
Howard.. 261 238 214 134 0.329 standard .904 lobe
here we are trying to use some of his head flows
The rattler is a marketing gimmick, so is the Thumper even n a low compression late 440 or 400 or 360 you can easily do better
I do not think I made any suggestions in this thread- still waiting for OP to verify mfg head cc- not like I don't trust them

another pair
Howard 267 213 ,450 Street Farce 2 .842 lobe
Howard 267 213 ,502
I already compared the Rattler

too swift a close requires more spring or bounce beats the **** out of your valvetrain comp 268 vs Lunati 268 prime example
 
Wyrmrider Said:
heck with 9:1 I might go 108 to get the intake closed earlier but would also depend on how much spread
With 10.5 I might go 114 like momma mopar did in the first place - that would cut the pressure

OK i redid the math with his spec's
65cc head
11.60cc head gasket (.053")
7.5 cc piston below deck(yes i now its above deck)

84.10 X(4.08" bore)709.15 Divided by 84.10= 9.43:1
9.43:1

The only variable to this is......
1- i didn't figure in the cc between the top of the piston down to the top ring on the piston.
2-We are still assuming the 65cc combustion chamber????????????????
Once that is physically checked. we can make a hard num

so i would say its a lot closer to 9.5:1 then 10.5:1
 
Garrett we have no idea what the seat timing/ duration is with Hughes cams and I do not see those lobes in Howards lobe list so I have no idea who's grinding that cam
I do not think he needs a much longer exhaust lobe
and I don't think he needs 107 or 109 LCA
223/236 is a lot of spread
"ur Whiplash cam is designed for basically stock, low compression engines. This cam will run on pump gas in a 340/360 with 8.6:1 or less compression and iron heads."
would like to make sure on the cc's but U are close
Op needs to go to google and check reviews of the XE275HL which is in the same ballpark and see if that kind of driving experience is what she wants
I'd sure go with one of the other grinds U picked but I have not tracked exhaust durations

just for giggles plot the intake close between the 267 108LCA cam and the 273 110LCA Cam (the 275HL is 64ABDC on a 110)
340 cam 279 210 .429 2899206 intake @.006
 
I just double checked both Summit and Speed Master and the CNC heads are showing a 68 cc chamber volume. With the Eddy/Fel Pro blue stripe .050 thick 11.2 cc head gasket this hits right around 9.5:1. Close to perfect if it's 91 octane fuel at the premium pump. Not far from being able to run well on 89 mid grade.
 
Garrett Ellison said:
I just double checked both Summit and Speed Master and the CNC heads are showing a 68 cc chamber volume. With the Eddy/Fel Pro blue stripe .050 thick 11.2 cc head gasket this hits right around 9.5:1. Close to perfect if it's 91 octane fuel at the premium pump. Not far from being able to run well on 89 mid grade.
Click to expand...
This is why he just need to CC the combustion chamber and/or take to a shop and have it done. no guessing, just done.
 
Last edited:
I'm on my phone but there's a few threads about Speedmaster flow numbers if that's what you need to know for sure.
 
The LCA is being decided around a 9.5 or/to 10.5 compression so they need a hard # of cc's for his head combustion chamber CC's.
Need more than average cc of the SM head.
 
OP
when you commit to a compression I'd pm AJFORM/S (look him up and have him give you his 2 cents on your dynamic Compression-
What we have is big heads 3:23 gears and a 4 speed
the mechanical compression will be fixed within a narrow window except for the head gasket
What do you figure your quench distence is
this is another necessary number
go above .050 and we have to drop the dynamic compression target and I'd prefer .030-.040
now we have some choice on our intake close point at .006
What we want to do i have as much dynamic compression we can get without pinging
but as much as possible to promote low and mid range torque as we have no converter to crutch on
 
Wyrmrider, Thank u very much for ur input in this thread and in my other threads. I really appreciate ur knowledge. Do u think milling the heads .030 would be of any benifit? Quench is .039. Head cc is 65.1-65.2 Kim
 
op says heads are 65,1-65.2
who cc.dthem kim?
quench is .039 with which gsket?
how far down are the decks at tdc
show all the calc for your compression ratio
 
I'm coming in at 9.8:1. I've been unable to find how much to mill the SM heads to decrease chamber the volume 1 cc, but milling the chambers to close to a 61-1/2 cc volume would yield 10.2:1. Providing all the sharp edges are smoothed out that's a pretty safe number even for 91 octane premium fuel with the .038 quench in play. It still would be good to see some timing events for the proposed cam to check the DCR out before adjusting it though. The Lobe number on the Howards 267-220 @ .05- .506 cam is HM2203372A 267 244 220 140 0.337
[email protected] / [email protected] / 220 @ .050 / and 140 @ .200, hope this may help with determining who grinds these so we can get some opening and closing events.
 
Last edited:
If were going to evaluate compression that close, all variable need to be verified.
Such as the pistons need to all be put back into the block and verified of above deck height (this may have already been done.)
On top of that we need to drop the piston down in the hole .050" of a inch and CC. piston
spec's says 7.5cc........When i did this on my .060" over piston, My piston was 7.35cc.

I think that a custom head gasket that don't have a bore size of 4.120 would help a little as well.
 
You must log in or register to reply here.
-

Back
Top