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Re: Critique my 340 build please ........
[Re: RebelDart]
#101519
08/08/08 03:31 PM
08/08/08 03:31 PM
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Joined: Feb 2004
Posts: 4,501
Gainesville,FL
goldmember
master
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master
Joined: Feb 2004
Posts: 4,501
Gainesville,FL
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Sounds like a nice streetable combo.My experience is with 360 and larger small blocks,I don't see any problem with your plan.I'd consider having the heads milled to get the compression up a bit,if the chambers are really 75cc. What machine shop are you using?
Last edited by goldmember; 08/08/08 03:36 PM.
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Re: Critique my 340 build please ........
[Re: RebelDart]
#101527
08/08/08 07:01 PM
08/08/08 07:01 PM
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Joined: Jan 2003
Posts: 8,144
Arkansas
340727dart
master
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master
Joined: Jan 2003
Posts: 8,144
Arkansas
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If you're using a head gasket with 0.039" compressed thickness, you should still have plenty of piston to head clearance with the iron heads.
IIRC, the chambers are about 0.100" or more deep.
I've got that same cam in my 340 and love it.
My pistons are 0.020" above the deck and I have plenty of piston to valve clearance. But the KB pistons have pretty generous valve reliefs.
That's the clearance you need to be concerned about.
Your life is not my fault.
My life is none of your business.
Speech is free only if you agree with those in control.
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Re: Critique my 340 build please ........
[Re: RebelDart]
#101529
08/08/08 07:52 PM
08/08/08 07:52 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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1st need ALL measurements: piston amt in/out of hole(deck height),amt(cc's) of piston dome, cc's of valve reliefs, CC's of heads,depth of open chamber recesses. So you can machine to achieve .035-040 quench & the CR you need(& 9.2 isn't enough) which will go with determining what head gasket you need & wondering what octane FUEL will you be useing? Thats too bad they are not being customer friendly but unfortunately that is all too common. Stay with it,you want this thing right.
live every 24 hour block of time like it's your last day on earth
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Re: Critique my 340 build please ........
[Re: UCUDANT]
#101530
08/08/08 08:26 PM
08/08/08 08:26 PM
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Joined: Apr 2007
Posts: 4,233
petaluma,ca. u.s.a.
west
master
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master
Joined: Apr 2007
Posts: 4,233
petaluma,ca. u.s.a.
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Quote:
If the pistons are .030 out of the hole I think your compression might be higher than you calculated. I think a 70 340 piston was .018 out of the hole and compression is rated over 10 to 1.
How big are the relief's in those pistons? Heads might be 72cc
i'm not an engine wizzard by any means but this is what i was thinking half way throuh your post.
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Re: Critique my 340 build please ........
[Re: RebelDart]
#101534
08/09/08 12:17 AM
08/09/08 12:17 AM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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[quote The TRW's we're using L2316F)have a 7.5cc relief. If I have to shave - so be it, but I need the compression so not sure the best route to take.
You will be milling the heads & probably not the dome. this calculator is very nice. http://kb-silvolite.com/calc.php?
live every 24 hour block of time like it's your last day on earth
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Re: Critique my 340 build please ........
[Re: RebelDart]
#101535
08/09/08 01:57 AM
08/09/08 01:57 AM
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Joined: Feb 2003
Posts: 1,665
Milwaukee, WI
Prince_Valiant
top fuel
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top fuel
Joined: Feb 2003
Posts: 1,665
Milwaukee, WI
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Without getting into the specifics of your clearance or lack there-of (I think you'll be fine, with decent compression to boot), I'll comment on your overal build:
Need more cam for the head flow you've got, and you need more carb.
As it sits, it should be a good safe mid/perhaps low 13 second car...provided you have good spark/timing.
However, at first I'm a little disappointed in the flow of the "worked" heads...if it's minor work, then that's good...but if they were going through and porting the crap out of them, then I at least hope that it was on a VERY pessimistic bench. With that cam, I think you would have wanted flow in the 270-280 cfm range. With the flow you've got, I'd want at a minimum the next step up, but likely something in the 240 @ .050, .530+ lift range...or better yet, a roller cam with similar duration @ .050 as your current cam.
Also I'd want probably a good Holley 700-750 DP for the best performance at the track.
All in all, as it sits, it's a great street-strip combo, no doubt.
1979 Dodge Lil' Red Express - 360 rwhp, 13.2 @ 103mph
1968 Coronet: 318, 2.76, 15.2 @ 92mph! (SOLD)
1976 Valiant: 360, 3.90, 12.90 @ 106 (SOLD)
1989 Shelby CSX #500/500
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Re: Critique my 340 build please ........
[Re: RebelDart]
#101536
08/09/08 03:05 AM
08/09/08 03:05 AM
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Joined: May 2008
Posts: 5,399
Aurora, Colorado
451Mopar
master
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master
Joined: May 2008
Posts: 5,399
Aurora, Colorado
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Here is the numbers I used:
Block Deck Height = 9.600"
Bore = 4.070" (0.030 over)
Stroke = 3.310"
Rod Length = 6.123"
Piston Height = 1.840" (TRW 2316)
Valve relief volume = 7.5cc (seems big, is this right?)
Est. Head Gasket Volume (0.040" thick) = 9cc
Cylinder Head Volume = 75cc
If the engine is the stock 9.60" deck height the piston should only be 0.018" above the deck, and the compression ratio calculates to 9.05:1
If the decks have been milled 0.012 to where the piston is 0.030" above deck, the compression calculates to 9.29:1
If you use a 0.020" head gasket (estimate 4.5cc) or mill the heads 0.020" the compression should be approximatly 9.76:1
I don't think the positive piston height will be a problem, but check the head chamber height to be sure. On my 360 heads the chamber was recessed 0.070"+.
The combination looks good for a dual purpose vehicle, but most likely mid to high 13's?
I don't know the cars weight, and the track altitude. Anyhow, to run 12's you will probbably need more cam and compression?
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Re: Critique my 340 build please ........
[Re: west]
#101537
08/09/08 06:55 AM
08/09/08 06:55 AM
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Joined: Jan 2003
Posts: 7,978
Bethel Ct
AdamR
master
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master
Joined: Jan 2003
Posts: 7,978
Bethel Ct
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Quote:
Quote:
If the pistons are .030 out of the hole I think your compression might be higher than you calculated. I think a 70 340 piston was .018 out of the hole and compression is rated over 10 to 1.
How big are the relief's in those pistons? Heads might be 72cc
i'm not an engine wizzard by any means but this is what i was thinking half way throuh your post.
That is correct but the actual compression of a stock 340 is lower the 10:1.
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Re: Critique my 340 build please ........
[Re: AdamR]
#101543
08/10/08 11:09 AM
08/10/08 11:09 AM
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Joined: Oct 2007
Posts: 2,808
Wisconsin
wkroncke17
master
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master
Joined: Oct 2007
Posts: 2,808
Wisconsin
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You have plenty of Cam,and use the 770...its way better to lean out a bigger carb than richen up a small one. My '72 Demon had a stock bottom end 360 w/MP .484/284 Cam,Holley strip dom intake,and Holley 750,3800 stall, 4:56 gear,SS springs,9x28 slicks and ran a best of 12.28 @ 108 mph. Now I did race it every weekend,so I had a lot of time to fine tune it.
Sounds like you want to be a little more streetable,so don't go crazy with the gear,3:91 sounds good,and don't be afraid to run SS springs on the street,they'll be just fine. You should be able to dip into the 12's no problem!
I don't like the way your machinist sounds,you're paying him good money for hopefully a good finished product,Don't be afraid to get info out of him.
I hope it all turns out well in the end!!
Best of luck!!
Wally.
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Re: Critique my 340 build please ........
[Re: wkroncke17]
#101544
08/10/08 12:08 PM
08/10/08 12:08 PM
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Joined: Feb 2003
Posts: 1,665
Milwaukee, WI
Prince_Valiant
top fuel
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top fuel
Joined: Feb 2003
Posts: 1,665
Milwaukee, WI
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The MP 484 cam is a bigger cam than that voodoo "268" cam by a healthy amount...even if it doesn't have the lift the the voodoo has.
241 @ .050 w/ 108 LSA for the MP vs 226 w/ 110 LSA for the voodoo...
The "voodoo" series has two cams in it's line-up, both available from summit that could do the job nicely...both MIGHT hit your goals, one certainly will.
The 60404 features 234/242 @ .050, .513/.533 lift, 110 LSA...with the mild porting, this cam stands a good chance of getting your ET goals provided the chassis is up to snuff...should be fine with your torque converter. With the aggressive ramps, it's should be comparable to the MP 284/484 cam in terms of power, but with better vacuum/idle, wider power band.
The 60405 will DEFINITELY get your goal (and perhaps more) and should have comparable if slightly better vacuum and idle to the MP 284/484 cam; but it'll make a healthy bit more power...specs are similar at 241/252 @ .050 on the split pattern cam, but with a wider 110 degree LSA (overlap is still greater due to the large exhaust duration vs the single pattern MP unit). Where this cam shines over the MP though is it's ramps...very aggressive (not the most aggressive; racer brown and hughes offer better...but the voodoo is probably the best you can exchange for at summit) featuring .533/.552. It's lift @ .300/.35/.400/.450 should all be significantly better than the MP unit as well...making the cam seem bigger w/o the all the poor idle/driveability of the MUCH bigger cams.
The caveat is, what springs are you running and are they suitable for either cam?
1979 Dodge Lil' Red Express - 360 rwhp, 13.2 @ 103mph
1968 Coronet: 318, 2.76, 15.2 @ 92mph! (SOLD)
1976 Valiant: 360, 3.90, 12.90 @ 106 (SOLD)
1989 Shelby CSX #500/500
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Re: Critique my 340 build please ........
[Re: RebelDart]
#101548
08/10/08 04:51 PM
08/10/08 04:51 PM
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Joined: Jan 2003
Posts: 8,144
Arkansas
340727dart
master
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master
Joined: Jan 2003
Posts: 8,144
Arkansas
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Just curious, why did you use Comp springs with the Lunati cam?
Those springs have a 1.900" installed height.
The recommended springs are Lunati P/N 73949. Their installed height is 1.650".
Your life is not my fault.
My life is none of your business.
Speech is free only if you agree with those in control.
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Re: Critique my 340 build please ........
[Re: 340727dart]
#101554
08/11/08 09:56 AM
08/11/08 09:56 AM
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Joined: Mar 2003
Posts: 756
North Florida
RebelDart
OP
super street
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OP
super street
Joined: Mar 2003
Posts: 756
North Florida
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Quote:
Quote:
These are what the shop installed - I told them what cam I was planning on using, they said these Comp springs would be fine - charged me 90.00 parts/(mostly)labor,. Should I change 'em out ?
Let me guess, the shop you used normally does chebby engines, and they figured what works in a chebby will work in a Mopar.
I went through the same thing. I was never happy with the way the engine revved.
Even after taking the correct springs to the guy he used another spring.
I ended up putting the correct springs on the engine and it really helped.
You are correct, sir. I'd rather not shell out another 100.00 on springs ...
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Re: Critique my 340 build please ........
[Re: RobX4406]
#101555
08/11/08 01:26 PM
08/11/08 01:26 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
It's a low 13's-high 12's combo if you can get it to hook. My car is similar with stock heads, less cam, and runs 102 in the 1/4.
The carb will be the choke point up top. Not near enough IMO.
naw, no way 12's. the cams too small. compression too low. Need at least 9.7:1 and a good 284/484 (something around 240 @.050). mill the heads to up the compression
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Re: Critique my 340 build please ........
#101556
08/11/08 02:34 PM
08/11/08 02:34 PM
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Joined: Apr 2006
Posts: 199
beentheredonethat
AverageJoe
member
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member
Joined: Apr 2006
Posts: 199
beentheredonethat
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Quote:
Quote:
It's a low 13's-high 12's combo if you can get it to hook. My car is similar with stock heads, less cam, and runs 102 in the 1/4.
The carb will be the choke point up top. Not near enough IMO.
naw, no way 12's. the cams too small. compression too low. Need at least 9.7:1 and a good 284/484 (something around 240 @.050). mill the heads to up the compression
Lots of opinions here .... even if he goes with the 150 shot of nitrous ?
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Re: Critique my 340 build please ........
[Re: AverageJoe]
#101557
08/11/08 07:27 PM
08/11/08 07:27 PM
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Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
RobX4406
I Live Here
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I Live Here
Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
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Quote:
Quote:
Quote:
It's a low 13's-high 12's combo if you can get it to hook. My car is similar with stock heads, less cam, and runs 102 in the 1/4.
The carb will be the choke point up top. Not near enough IMO.
naw, no way 12's. the cams too small. compression too low. Need at least 9.7:1 and a good 284/484 (something around 240 @.050). mill the heads to up the compression
Lots of opinions here .... even if he goes with the 150 shot of nitrous ?
Tuned right that will get into the 12.90. Don't need a lot of motor to go that fast if it hooks and runs right. It might run high 11's on juice.
So I guess a 340 with 3.91's, short tires and a 214*/224* at .050 cam can't run low 13's at over 101? I clearly did something wrong. 
The listed engine is capable of about 380-400hp, maybe a smidge more, if the carb is changed to a 750 or better. That's enough HP to push a 3200-3300# car to a 13.00 or slightly better.
Don't need huge cams with lots of duration to get a car to run low 13's. He won't get near the low 12's without juice, and would need to up the cam/compression/carb/gear to get there on motor.
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