Help with camshaft for 340/416

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Chris Hazell

Chris Hazell

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Hi guys, I’m new to the forum. Looking for recommendations on a camshaft. I recently purchased a 69 dart gts. The motor 340/416 had already been built and not by the owner i bought from so not exact on some parts. I had to remove the engine to deal with loose flex plate bolts so I decided to add a few things it had iron heads i am adding eddy RPM prefomers and 1.5 hughes rocker set up its a hydraulic flat tappet cam set up. 800cfm holley, single plane high rise mopar intake. I’m not exactly sure on CR I’m guessing 10:1???? Its got ross pistons with eagle 4340 crank and h beam rods. 727 with no stall 3.91 sure grip rear end. It will be a weekend cruiser i want to maximize the cam so the heads can work to their potential. I don’t mind it a little lumpy also not against adding a small stall convertor. Thanks!!!!!
 
Chris Hazell said:
I’m not exactly sure on CR I’m guessing 10:1????
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Gonna take more than a guess on compression. Cam duration needs to know the CR spot on. The car I bought had paperwork from the previous owner. I found him in Ohio and called him up. One question was CR. 9.5 replacement pistons he said. So I order a 268 cam. Turns out 8.0 was more like it. Not that it was a complete dog, but far from what it should have been.
 
what's your cranking compression
ross pistons and a customer name should get you the data
and you do need it
 
Chris Hazell said:
I know that’s the tough part motor is out not sure how to get that number exactly
Click to expand...
It's not hard to find out. The engine is out of the car. Your replacing the heads so look at the cc on the new heads (combustion chambers cc) then measure how far the pistons are in the hole. Cc the piston tops If they are flat tops with relief cuts. The figure out what gaskets your gonna use and plug all that info into a compression calculator I like this one. Engine Compression Ratio (CR) Calculator
 
fratzog lover said:
Gonna take more than a guess on compression. Cam duration needs to know the CR spot on. The car I bought had paperwork from the previous owner. I found him in Ohio and called him up. One question was CR. 9.5 replacement pistons he said. So I order a 268 cam. Turns out 8.0 was more like it. Not that it was a complete dog, but far from what it should have been.
Click to expand...
dartfreak75 said:
It's not hard to find out. The engine is out of the car. Your replacing the heads so look at the cc on the new heads (combustion chambers cc) then measure how far the pistons are in the hole. Cc the piston tops If they are flat tops with relief cuts. The figure out what gaskets your gonna use and plug all that info into a compression calculator I like this one. Engine Compression Ratio (CR) Calculator
Click to expand...
ya that was my plan this morning pulled the heads to find some substantial scoring in the cylinders not sure what went on here as I bought the car with the motor in it. Needlessly to say pretty bummed out. Going to take it to the machine shop to see it it can be fixed, I’m suspicious they are too deep.
 
Hey Chris;

Congrats on the purchase. May it serve you well!
On the cam recommendation, your really missing a ton of information. The actual compression ratio should be known and if you could, tell us what your ideal cruising speed will be in rpm’s.

Cam companies give there cams a operating rpm range or band. This is a generalization but it is close enough to what the cam will do. The bigger the engines cubic inch displacement and/or stroke, the (slightly) lower that rating will be.

Also inform us of the cars weight, gear ratio & tire size. If you want to cruise the Hwy. or just the Boulevards at 40/45 miles an hour. I’m not always for the most aggressive lobe profile. They have there place. Just need to understand where your at, what your thinking, where you want to end up.

Do you care if it was a Hyd. or Solid lifter cam?
Solid lifter cams offer more top end rpm range if your cylinder heads support it. (AKA - ported heads)

(If I’m not back so fast, Wyrmrider is pretty good with cams.)

Chris Hazell said:
Hi guys, I’m new to the forum. Looking for recommendations on a camshaft. I recently purchased a 69 dart gts. The motor 340/416 had already been built and not by the owner i bought from so not exact on some parts. I had to remove the engine to deal with loose flex plate bolts so I decided to add a few things it had iron heads i am adding eddy RPM prefomers and 1.5 hughes rocker set up its a hydraulic flat tappet cam set up. 800cfm holley, single plane high rise mopar intake. I’m not exactly sure on CR I’m guessing 10:1???? Its got ross pistons with eagle 4340 crank and h beam rods. 727 with no stall 3.91 sure grip rear end. It will be a weekend cruiser i want to maximize the cam so the heads can work to their potential. I don’t mind it a little lumpy also not against adding a small stall convertor. Thanks!!!!!
Click to expand...
 
Every cam choice is gonna be a set of compromises, most are gonna leave power on the table, especially where your on the mild side of lumpiness and stall.

I’ll use comp cam xe line as an example, your 3 choices would be xe268hl xe275hl or cr285hl.
or similar from other brands, depending on your CR you don’t want go too small for detonation reasons.

Xe275hl cam or similar would be my guess, It’s really up to you depending what you want out of your machine.
 
So an update on this ordeal. The motor (not built by me) was basically pooched from some kind of oiling issue. Anyway we have salvaged the block machine shop is cleaning it up now. Here is what we will be building. 416 stroker 10:1 comp, eddy rpm performer heads, eddy air gap intake, hughes 1.5 roller rockers with hyd flat tappet set up, 750 cfm holley, headers 3” dual exhaust, 727 automatic 391 8-3/4 rear 14” wheels car weights 3250lbs i can add the stall to suit. Like to have it living between 2-5500rpm, street car but on the hot side but still drivable, Want the classic lopey idle. Love some feedback from you guys on your thoughts on cams.
 
Chris Hazell said:
So an update on this ordeal. The motor (not built by me) was basically pooched from some kind of oiling issue. Anyway we have salvaged the block machine shop is cleaning it up now. Here is what we will be building. 416 stroker 10:1 comp, eddy rpm performer heads, eddy air gap intake, hughes 1.5 roller rockers with hyd flat tappet set up, 750 cfm holley, headers 3” dual exhaust, 727 automatic 391 8-3/4 rear 14” wheels car weights 3250lbs i can add the stall to suit. Like to have it living between 2-5500rpm, street car but on the hot side but still drivable, Want the classic lopey idle. Love some feedback from you guys on your thoughts on cams.
Click to expand...


You have adjustable rockers. Pass on the hydraulic lifters. That would be doing yourself a solid (pun intended). Hydraulic lifters suck buttermilk. Lashing valves is easy and you should do it once a year if everything is correct.


Contact Mike at B3 racing engines and have him hook you up with his geometry correction kit. You need it.
 
ask mike jones
you need more compression with 275 cam vs 268 and I do not know where you are at or what rev range you need with your build, gars etc
but you are correct lunati has maybe 25 hp over the comp
are you thinking solid or hyd?
if you already have adj rockers get the b3 kit and go sft with edm lifters
 
Wyrmrider said:
ask mike jones
you need more compression with 275 cam vs 268 and I do not know where you are at or what rev range you need with your build, gars etc
but you are correct lunati has maybe 25 hp over the comp
are you thinking solid or hyd?
if you already have adj rockers get the b3 kit and go sft with edm lifters
Click to expand...
I was planning on Hyd lifters, just received my hughes 1.5 shaft and roller rocker kit. We are about 2800ft-3000ft here
 
same answer
Jones will tell you if you should swap for 1.6 rockers
still recommend a SFT with edm lifters
fill out his cam request online
 
Chris Hazell said:
14” wheels car weights 3250lbs i can add the stall to suit. Like to have it living between 2-5500rpm, street car but on the hot side but still drivable, Want the classic lopey idle. Love some feedback from you guys on your thoughts on cams.
Click to expand...

Thumper.
you got the stroke to pull it off . But it's gonna be a lil hard on gas
279/297/107+5/118 compression, Ica of 62/ 100power
227/[email protected], lifts of .486/.473 @1.5

This will like 11/1, and alloys
Static compression ratio of 11:1.
Ica of 62/ 600ft elevation
Effective stroke is 3.20 inches.
Your dynamic compression ratio is 9.00:1 .
Your dynamic cranking pressure is 187.33 PSI.
V/P (Volume to Pressure Index) is 184
Torque monster, with attitude
run any gear, any TC,
Hang the heck on.
Do not run turndowns,lol, you'll have a cloud of dust everywhere you go.
14" wheels? seriously?
 
Last edited:
AJ/FormS said:
Thumper.
you got the stroke to pull it off . But it's gonna be a lil hard on gas
279/297/107+5/118 compression, Ica of 62/ 100power
227/[email protected], lifts of .486/.473 @1.5

This will like 11/1, and alloys
Static compression ratio of 11:1.
Ica of 62/ 600ft elevation
Effective stroke is 3.20 inches.
Your dynamic compression ratio is 9.00:1 .
Your dynamic cranking pressure is 187.33 PSI.
V/P (Volume to Pressure Index) is 184
Torque monster, with attitude
run any gear, any TC,
Hang the heck on.
Do not run turndowns,lol, you'll have a cloud of dust everywhere you go.
14" wheels? seriously?
Click to expand...
Stock 14” rims was what i meant. Going to eventually squeeze some 15 rims on.
 
You know yur building a motor that can spin 14s to like 100 mph, right?
Well at least you won't be blowing up the rear end anytime soon, unless it has no SG, then move over, lemmee drive; I give it 30 minutes tops..lol
 
AJ/FormS said:
You know yur building a motor that can spin 14s to like 100 mph, right?
Well at least you won't be blowing up the rear end anytime soon, unless it has no SG, then move over, lemmee drive; I give it 30 minutes tops..lol
Click to expand...
Haha yep Gotta keep the tire guys in business too. I will work on suspension after the motor is dialed in.
 
thumper
you gotta be kidding
the lobes are not bad but the exhaust is way too long compaewd to the intake
that said do not run one with much compression
 
Wyrmrider said:
thumper
you gotta be kidding
the lobes are not bad but the exhaust is way too long compaewd to the intake
that said do not run one with much compression
Click to expand...
I know but check out
Chris Hazell said:
727 with no stall 3.91 sure grip rear end. It will be a weekend cruiser i want to maximize the cam so the heads can work to their potential. I don’t mind it a little lumpy also not against adding a small stall convertor.
Click to expand...
What we have here is a 227* cam;
with 74* overlap for lots of attitude;
with an early closing intake for lots of compression, and a resulting strong bottom end so he can run his tiny convertor;
low lift for a long street life;
a 107 LSa for a lil power bulge thru the midrange and over the top to go with that overlap;
And the only thing it costs is fuel-economy which with 3.91s there won't be any anyway.
I thought finally, a combo to justify a Thumpr,lol.
I mean look at the effective stroke on that combo; 3.20 inches. You'll never get that on any other combo save a stroker, and the very strong VP is the result of that, in spite of the 279* advertised intake duration.
I have yet to see a better candidate here on FABO, for this cam. It works the combo, and it fits in the OPs guidelines.
Am I wrong?
 
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