340 stroker cam

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249 at .050 you should be running over 12:1 Static compression. Unless you intentionally went too high on your duration to drop your DCR for use with low octane fuels. At 10.5:1 static I feel you would be better suited at around 230 to 233 duration at .050. using premium unleaded. I cannot speculate lift without knowing the flow numbers of the heads. Those heads you got are a great flowing set, but after the port work, I would need to know the flow numbers at lift values to give an accurate lift suggestion. Sure you can pick an off the shelf cam, but I personally think your over cammed for your current setup and making less power than you could be. Also what’s your trap rpm? 28 inch tire and 4.30s assuming 1:1 final drive, I’m guessing your trapping somewhere around 6300 1/4 mile? I need more info...
 
Sprayin73 said:
249 at .050 you should be running over 12:1 Static compression. Unless you intentionally went too high on your duration to drop your DCR for use with low octane fuels. At 10.5:1 static I feel you would be better suited at around 230 to 233 duration at .050. using premium unleaded. I cannot speculate lift without knowing the flow numbers of the heads. Those heads you got are a great flowing set, but after the port work, I would need to know the flow numbers at lift values to give an accurate lift suggestion. Sure you can pick an off the shelf cam, but I personally think your over cammed for your current setup and making less power than you could be. Also what’s your trap rpm? 28 inch tire and 4.30s assuming 1:1 final drive, I’m guessing your trapping somewhere around 6300 1/4 mile? I need more info...
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His final drive is .80 (OD-4spd)
I’m not sure this is a track I my car. So I have to disagree on the 12-1+ ratio for this instance. The cam isn’t overly large and can be fine in the street with what he is running. (Quality of gas also comes to mind, no sense pushing it.)
dodgedifferent2 said:
I mainly drive on the street now with the kids.
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Is this a track car only or mostly? Sprayin73’s high ratio notation had me wondering. I’m pretty sure your driving this is in the street a good bit. Am I correct? As in more street than track.
 
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I'd call BAM and talk to him about that lifter failure. He might have you send in the remaining 15 lifters for inspection and, maybe, may help you with that broken lifter.

If you like the cam you can send it back to Lunati and they can repair and regrind the bad lobes.
 
Yes .80 is his overdrive 4th gear, most who run that trans trap in 3rd, or 1:1, not 4th, that was my implied question stating that I assumed he’s in 1:1 or 3rd. Rumble fish, I’m spot on using premium pump gas. Opinions are like buttholes everyone’s got one. It’s up to him and his intended use in the end after all. He asked the question, I answered to the best of my knowledge to maximize efficiency.
 
Your point of view is more of the drag strip and not a double duty or a car that runs the street. Otherwise, I’m with you.
You say your spot on with pump gas and I’ll disagree because of this one very factual point, pump gas quality varies. With that, why push it? If you can get it, GREAT! Then comes the day you get crap gas.....
Also, not to be a dick, but the “a implied question” should be directly asked. It eliminates confusion or a misreading.

Your words here “Opinions are like butt holes...” sounds defense, don’t be. I’m not attacking. Just sayin, just incase. I’m not here to challenge. Just here to talk and enjoy.

Sprayin73 said:
Yes .80 is his overdrive 4th gear, most who run that trans trap in 3rd, or 1:1, not 4th, that was my implied question stating that I assumed he’s in 1:1 or 3rd. Rumble fish, I’m spot on using premium pump gas. Opinions are like buttholes everyone’s got one. It’s up to him and his intended use in the end after all. He asked the question, I answered to the best of my knowledge to maximize efficiency.
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Sprayin73 said:
Yes .80 is his overdrive 4th gear, most who run that trans trap in 3rd, or 1:1, not 4th, that was my implied question stating that I assumed he’s in 1:1 or 3rd. Rumble fish, I’m spot on using premium pump gas. Opinions are like buttholes everyone’s got one. It’s up to him and his intended use in the end after all. He asked the question, I answered to the best of my knowledge to maximize efficiency.
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rumblefish360 said:
Your point of view is more of the drag strip and not a double duty or a car that runs the street. Otherwise, I’m with you.
You say your spot on with pump gas and I’ll disagree because of this one very factual point, pump gas quality varies. With that, why push it? If you can get it, GREAT! Then comes the day you get crap gas.....
Also, not to be a dick, but the “a implied question” should be directly asked. It eliminates confusion or a misreading.

Your words here “Opinions are like butt holes...” sounds defense, don’t be. I’m not attacking. Just sayin, just incase. I’m not here to challenge. Just here to talk and enjoy.
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It’s interesting this discussion on CR and fuel requirements.

I don’t quite agree with sprayin that he needs LESS cam...but I certainly agree the OP could use more CR.

As far as pump gas goes, other than ethanol content the regs for premium pump gas are pretty tight. The lower grades are pretty loose. They can use a ton of fillers and crap, where premium pump fuel can’t.

I’ve been beating the higher than “normal” pump gas compression ratios since I was just out of high school. Since I’ll turn 40 here in a bit (inside joke) you can add up the time.

When you get the CR up, and the cam timing correct for the application. The engine is far happier, easier to tune, cleaner and just far more enjoyable to drive.

But, you can’t just slap some crapola together and make it happen. And, as you say...you have to consider the application. If you are pulling a trailer and have 3.08 gears, likely anything over about 9.8:1 is going to be an issue.

For the guys who are willing to use a systems approach, 12:1 on premium pump gas is quite easy to do. Also, I always like to mention how important expansion ratio is, and how much it is ignored. ER is a byproduct of CR. Ignoring ER makes the engine less efficient.
 
@yellow rose

I can agree with that and done similar. There is one thing I noticed about the NY/LI pump swill, once I’m out of state, the car picks up and gets better mileage when there is no NY gas in the tank.

Current engine is 11.6-1 w/a HR @ 224 @ .050.
Runs great on the pump swill. I can wait to get outta state for better fuel!
 
Rumble fish,
Brother I in no way meant that defensively. Was still drinking my coffee, was meant to be a joke but I forgot to add “ and this was my opinion, not butthole”. No I stand by what I said, the OP said he was using 360-1 heads from Indy, which are aluminum closed chamber 65cc heads if I remember. I just had to look them up to be sure because I had forgotten. Indy site even said “for use with 11:1 compression and up on large cubic inch engines pump gas or race”. Your correct on the implied question I should have been more direct. My calculations are saying either pull back duration to work with the lower compression, or up the compression to work with the cam. The heads are great so no issue there. The Dynamic compression ratio is where it’s all at, static compression ratio is just a reference point, the 12:1 SC on pump gas shouldn’t scare anyone. Similar to what the OP did with cam selection 10.5:1 with 249 at .050 is more like a DCR of 9.2-9.8:1. So if he shortens the duration it would pull his compression ratio back up closer to his static or, if he upped his compression to meet the cam that he has needs, it would accomplish the same thing and work more efficiently. So compression up, or cam down. That’s what I’m saying. Safe on pump gas 91 with those heads either way.
 
Sprayin73 said:
Rumble fish,
Brother I in no way meant that defensively. Was still drinking my coffee, was meant to be a joke but I forgot to add “ and this was my opinion, not butthole”. No I stand by what I said, the OP said he was using 360-1 heads from Indy, which are aluminum closed chamber 65cc heads if I remember. I just had to look them up to be sure because I had forgotten. Indy site even said “for use with 11:1 compression and up on large cubic inch engines pump gas or race”. Your correct on the implied question I should have been more direct. My calculations are saying either pull back duration to work with the lower compression, or up the compression to work with the cam. The heads are great so no issue there. The Dynamic compression ratio is where it’s all at, static compression ratio is just a reference point, the 12:1 SC on pump gas shouldn’t scare anyone. Similar to what the OP did with cam selection 10.5:1 with 249 at .050 is more like a DCR of 9.2-9.8:1. So if he shortens the duration it would pull his compression ratio back up closer to his static or, if he upped his compression to meet the cam that he has needs, it would accomplish the same thing and work more efficiently. So compression up, or cam down. That’s what I’m saying. Safe on pump gas 91 with those heads either way.
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LOL...this is NOT the kinder, gentler me with a new login. I swear this is NOT me!!!!
 
11.8:1 Flat top with those heads will like 240-242 at .050 duration. Lift is another story, that needs to be matched to your head flow numbers.
 
I am no cam expert and will not pretend I am. So let's reverse think.

The duration bleeds off static pressure to run at optimal sweet spot. (Overlap)

So now, if we decreased duration, the static pressure would stay, rather than bleed down?

Again I am no expert.
 
I don’t think any of us are cam experts. If I was I’d be making bookoo bucks doing custom cam grinding. In a nut shell and very lay terms yes. The higher you go on duration , hang open time, the more bleed off of cylinder pressure before the valve closes. To counter act you would up the compression. Or bring duration down to acceptable levels for the compression that exists. But more compression, and more duration equals more power and a higher RPM potential. As with all things, the higher you go, the less street manners you will have.

Not sure if I posted this here already or not, may have been another thread. I like to start a build based off what the car is planned to do. Next select the heads needed to accomplish that, then I select a camshaft Duration that will put me in the RPM range I want to be, The minimum lift possible for the best flow numbers of the head, given the use of the car. Then bring compression up to match that duration. Then dyno and buy converter based off torque output from results. Regardless of cubes this process works for me, smaller cubes less torque, higher cubes more you get the idea, but trap rpm will be targeted by the build and gear / tire size.

Remember this info is only good on a naturally aspirated, no bottle setup. If you were to get into power adders that changes everything.
 
Sprayin73 said:
I don’t think any of us are cam experts. If I was I’d be making bookoo bucks doing custom cam grinding. In a nut shell and very lay terms yes. The higher you go on duration , hang open time, the more bleed off of cylinder pressure before the valve closes. To counter act you would up the compression. Or bring duration down to acceptable levels for the compression that exists. But more compression, and more duration equals more power and a higher RPM potential. As with all things, the higher you go, the less street manners you will have.

Not sure if I posted this here already or not, may have been another thread. I like to start a build based off what the car is planned to do. Next select the heads needed to accomplish that, then I select a camshaft Duration that will put me in the RPM range I want to be, The minimum lift possible for the best flow numbers of the head, given the use of the car. Then bring compression up to match that duration. Then dyno and buy converter based off torque output from results. Regardless of cubes this process works for me, smaller cubes less torque, higher cubes more you get the idea, but trap rpm will be targeted by the build and gear / tire size.

Remember this info is only good on a naturally aspirated, no bottle setup. If you were to get into power adders that changes everything.
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The only issue with reducing duration is how much will it affect the RPM he needs or wants. If he pulls the duration too far back, he will either give up RPM or will have to blow out the LSA to get some RPM back, which will kill the mid range.
 
dodgedifferent2 said:
So if I boost compression with a piston change from dish to flat top I can increase compression to 11.8 then go with a smaller camshaft?
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Current engine, .030-360, zero deck flat tops, Trick flows, .027 X 4.04 head gasket , 11.6-1, HR224@050, 93 octane, will tune it up more later and see what’s what.
 
Agreed, also consider at his current compression the RPM advantage is lost with the current cam, so the cam makes power to 7400 example, his engine runs out before 7400 is reached. So if he’s starting to fall off at 6800 what’s the point of a 7400 cam. I think we’re on the same page. If he pulls cam down to match current compression he most certainly looses the higher rpm that cam he has now is capable of, 100% correct, but since the engine runs out of steam before then anyway, he will make more peak power at 6800 with the smaller duration cam, than he could anywhere on the rpm range of the current cam. Those RPMs are for example purpose only.

Vice versa, pulls up compression, to match the current cam, he will be making peak horse power up at 7400. Resulting in more power than the lower compression with smaller cam, and even more power than what he has now with the higher duration and lower compression current setup. Yellow I think we’re eye to eye on this, just saying it slightly different. But same thing.

End of story is, pull duration with your current setup, you’ll make more power than you make now, but at a lower peak rpm. Or up compression to meet that cam and you’ll make even more power than that, higher up as the cam was designed.
 
dodgedifferent2 said:
So if I boost compression with a piston change from dish to flat top I can increase compression to 11.8 then go with a smaller camshaft?
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Don't let them talk you into changing your pistons, Just put one of the smaller cams that you wanted or a custom one.
 
rumblefish360 said:
Current engine, .030-360, zero deck flat tops, Trick flows, .027 X 4.04 head gasket , 11.6-1, HR224@050, 93 octane, will tune it up more later and see what’s what.
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Rumblefish,
Now that combo is right on the edge of pump gas, really about a point high for that camshaft, 10:1 would be better. Or bring your duration at .050 up to around 246. You will likely need race fuel, or jet up and pull timing to try to get it right on pump gas, without detonation. If that’s where your coming from in your posts, I get it. That’s comparing apples to oranges though, Quality pump gas would be essential with your combo. But with the juice rollers ramp profile coming into effect, they act different then flat tappet. In such a case you might be fine. So let us know how that goes...
 
Thanks, I agree, a miscalculation is what lead to this. So far, it’s good. Runs a little hot but then again the OE ‘67 Cuda’s V8 radiator (excellent shape!) could be a bit small. It has a shroud and a MP 5 blade viscous fan. (Excellent unit!) The temp gauge is also in question.
 
273 said:
Don't let them talk you into changing your pistons, Just put one of the smaller cams that you wanted or a custom one.
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The engine started as an iron headed max ported w2 with w5 ports with 62cc or 58cc chambers. Hence the reason for the dished pistons.
The car was meant for more strip than street but it morphed when I met the wife with 2 kids and I already was a full time single father.

A block change due to oil seepage from the backside of the block. I took the rotating assembly and stuffed it into another block. I literally fell into some indy heads that i could not pass up during reassembly.

Now i have 3 kids plus the new baby and apparently another in the oven. So 5 kids. All the kids love the car, even the mustang loving 16 yr old boy. Hence the reason for mainly street now.
With the family dairy farm, working a 40 hr full time job and keeping the garden up to support the chaos leaves no time for track days.

Now I found the paper work for the indy heads and i had the wrong camshaft.
Camshaft is lunati 40200734
Advertised Duration (Int/Exh): 285/293; Duration @ .050 (Int/Exh): 255/263; Gross Valve Lift (Int/Exh): .600/.600; LSA/ICL: 110/106; Valve Lash (Int/Exh): 016/016; RPM Range: 3200-7200

Springs are psi ct1240
  • 1.500 OD dual
  • 1.085 - .790 in ID
  • .780 max lift
  • 250 lbs @ 2.030 installed height
  • 610 lbs @ 1.250 open pressure
  • Spring rate 462 lbs
  • Coil Bind 1.200

I did not go extreme with the head porting.
Head flow numbers
.100--77.2
.200-- 148.6/108.6
.300---203.2/158.3
.400---249.7/197.4
.450--267.3/206.8
.500--286.5/214.1
.550--298.8/220.9
.600--303.1/228.2
.650---308.4/230.1
.700--310.7/231.6
 
I think the problem is finding a camshaft with a lower duration & lift as so to still being able to use the springs.

Have you given any thought to perhaps back up a step to a solid lifter cam. Considering it is more of a street car now to enjoy? A good solid will still produce good power and RPM. The overall package for the swap should not be to expensive.

Strictly as an example;
MP’s 296/.557 w/1.6 rockers = .594 lift, minus the lash, .028/.032 as per MP which seems loose to me but...!!!
Something of the sort that’s still lifting the valve up good with a duration more in line with the compression and gear ratio.

Just food for thought as a possible route.
 
I ran the 20-740-9 (Comp XR286R) for many years in my old 410 engine. The car ran great (about 30% street, 70% strip). That engine was 10.8:1 compression on gas most of its life, but I switched to e85 in its last few years. It ran high 10.7's on a typical summer day (10.57 was its best). This was with ported Edelbrocks (from Ryan at Shadydell) that flowed 293@ 0.600.

Edit: I was using Comp 939 springs, set up at 1.85" (a lot less spring than what you currently have).
 
I ran a 260/264° @ .050, mid 600" lift flat solid in a 10.8-1 408 and it was great. With ported Edelbrocks it ran 6.57 @ 3260# on pump 93. These 4" engines have tons of bottom end so don't be afraid of duration.
 
flyfish said:
I ran the 20-740-9 (Comp XR286R) for many years in my old 410 engine. The car ran great (about 30% street, 70% strip). That engine was 10.8:1 compression on gas most of its life, but I switched to e85 in its last few years. It ran high 10.7's on a typical summer day (10.57 was its best). This was with ported Edelbrocks (from Ryan at Shadydell) that flowed 293@ 0.600.

Edit: I was using Comp 939 springs, set up at 1.85" (a lot less spring than what you currently have).
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I like it.... Xtreme Energy 248/254 Solid Roller Cam for Chrysler 273-360
.614/.620 lift with the 1.6’s.
 
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