Thoughts on this cam

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James Hurt

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For a 340 stroker, actually 418 10:1 static compression ratio. Cam @.050 231/239 GVL .535/.550 LSA 110/106 hydraulic roller. Speedmaster heads with very mild port work. Intake is high rise M1 single plane. Dougs headers and a Holley sniper efi. I already have all these parts. Plan on a tkx transmission.
 
For what? Road racing? Drag racing? Street car? It’s a cam that’s for sure.
 
Don't see anything wrong with that plan at all. It we be a torquey beast, that's for sure. Welcome to the site. Cam talk always opens up a can of worms, just be prepared...:)
 
OldmanRick said:
Don't see anything wrong with that plan at all. It we be a torquey beast, that's for sure. Welcome to the site. Cam talk always opens up a can of worms, just be prepared...:)
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I put my feelings in a jar before I decided to ask for an opinion.
 
I don’t mind it for 418 inches with a stick and 3.91 gears but on a 106cl the sniper may have a hard time at idle. Do you have power brakes? Something to think about. I’d also like to see more lift than that even on a street car.
 
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TT5.9mag said:
I don’t mind it for 418 inches with a stick and 3.91 gears but on a 106cl the sniper may have a hard time at idle. Do you have power brakes? Something to think about. I’d also like to see more lift than that even on a street car.
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Yes it has power brakes.
 
I think you're right in the ballpark but agree about the 106 centerline , I don't know from experience because I've never had a hot fuel injected small block Mopar but I have read that overlap can be not so good when tuning fuel injector systems. Also I don't really see the need for more lift with those heads I don't feel you're really gain much after 550 JMO
 
K.O. SWINGER said:
I think you're right in the ballpark but agree about the 106 centerline , I don't know from experience because I've never had a hot fuel injected small block Mopar but I have read that overlap can be not so good when tuning fuel injector systems. Also I don't really see the need for more lift with those heads I don't feel you're really gain much after 550 JMO
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Don’t the speed masters flow pretty good up near .600? I’m going from memory here trying to remember a flow chart.
 
Maybe 10 CFM from 500 to .600 but they're definitely slowing down a lot with a Stockport now the CNC 190s do much better at high lift
 
I've run FT hydraulic cams in the 230/235/108 range and produced 9.5 to 11.0 in of vacuum in 340/360 cu in engines with a good initial curve. I have to think with a 4" arm you should at least be in that range. Not sure if the sniper system you have is laptop tunable, but some internet searches show some are running big Roller solids in the 7/8 vacuum range, albeit with some Pro tuning help?
 
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Get your ICL on 104 degrees and at least 112 of LSA to assist with vacuum on the power brakes. According to some people that have worked with the snipers on engines at this level, 112 is the minimum LSA that the snipers don’t have issues with. I wouldn’t go too far past those numbers on .050 duration. The more lift you add with a hydraulic roller, the wider the spread gets between the .006-.020 (advertised) duration gets from the .050 Duration. But I would still open the valves as much as practical. The peak flow of .600 is a good place to open the valve to because you’re increasing the duration in the .500 lift range. Holding the valve at peak flow longer is very beneficial with a four inch crank. You’ve got the rod ratio at 1.53 so that piston is not only displacing more mixture, it is also doing it at a faster rate with the increased piston velocity.
 
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Solid rollers are definitely a better option if done correctly!
 
Well, you have to start somewhere!
I think your choice is as good as any. And unless there is an IDENTICAL combo that has been dyno tested, no way of knowing how that cam will perform.

Agree that sol lifters would be a good idea. No pump or bleed down to worry about; just keep the lash tight, 0.004-6" hot.
Disagree about valve lift. While flow might be levelling off at the peak lift of heads, more lift means a 'fatter' lobe [ more area under the curve ] at lower lifts where the valves are open longer.
 
James Hurt said:
For a 340 stroker, actually 418 10:1 static compression ratio. Cam @.050 231/239 GVL .535/.550 LSA 110/106 hydraulic roller. Speedmaster heads with very mild port work. Intake is high rise M1 single plane. Dougs headers and a Holley sniper efi. I already have all these parts. Plan on a tkx transmission.
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That cam is a soggy mo'fkr.
WEAK!
 
OldmanRick said:
I've run FT hydraulic cams in the 230/235/108 range and produced 9.5 to 11.0 in of vacuum in 340/360 cu in engines with a good initial curve. I have to think with a 4" arm you should at least be in that range. Not sure if the sniper system you have is laptop tunable, but some internet searches show some are running big Roller solids in the 7/8 vacuum range, albeit with some Pro tuning help?
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The sniper is laptop tunable.
RIBOATSERVICES said:
Have the Lunati version of that in my 416. Idles at 800, plenty of vac for brakes, and plenty of torque on the street.
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Mine is the Lunati version. Did you have any problems with the hydraulic roller lifters?
 
My 408 w/ Trickflow 190's has a cam that is in the same ballpark as yours, dyno'd @ 448HP and 500TQ, Howards custom grind, hydraulic roller lifters. 1.6 rockers. Lots of vacuum. I am running a low geared reverse manual valve body 904 transmission with 3:55 suregrip.
My aim was primarily for a streetcar with an occasional 1/8 or 1/4-mile pass.

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