360 Cam Advice.

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Ben A...

Ben A...

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Hey there,
First, I'm new to this so I need guidance. Second, if cam recommendation posts are pesky then let me know and I'll delete this! I read quite a few on here, but I'm worried I'll pick a cam that will require a bunch of other modifications to the setup for it to work properly.

I'm rebuilding my first car engine (LA360) and I've reached out to Comp Cams for advice on best cam choice, but I've been given a few options (my fault, I requested a couple times). I'm curious to know what you think is the best way to go.

This is just a street Duster, but I would like to make it as 'performance' as I can. I do like a lumpy idle.

I assume no matter what I'll need to chance the pushrods? But I'm hoping to pick a cam that doesn't present me with a range of other issues/purchases regarding vacuum, springs, valve clearance and whatever else I'm not considering...

I should note, when I requested help from Comp Cams I gave a few different stall speeds because at the time I wasn't sure what I had. But now I know it's 2600. So they gave me a range of options here for 1500-2600 stall.

Cam reccos:

Setup:
I know my setup could be better but I've spent all my money so it remains for now. Down the road I'll change the rear end, get a bigger carb and put rollers in etc..

73 Duster
LA360 swapped
A904 with TF2
7 1/4 Rear with 2.76 ratio (will change when it blows up)
26" Tire height
2600 TC stall speed
~9.5-10CR
Electric distribution
Holley 650DP
Old Holley Street Dominator single plane intake
Edelbrock Performer RPM heads with 2.02 intake
Stock rockers
Hydraulic Flat Tappet
Flat top pistons
Long tube headers
Power steering (no power brakes)
​
Thank you for any help,
Ben
 
@AJ/FormS is needed. I bet he recommends (and me too) that you do a rear end swap first. Don't build the engine around that rear end, gear ratio, and those tall tires. A stock 360 with a 3.55 or more has plenty of power to spin those tires half way down the block.
 
toolmanmike said:
@AJ/FormS is needed. I bet he recommends (and me too) that you do a rear end swap first. Don't build the engine around that rear end, gear ratio, and those tall tires. A stock 360 with a 3.55 or more has plenty of power to spin those tires half way down the block.
Click to expand...
Sounds like a wise move, does the gear ratio in the rear end greatly affect cam choice? Could I just select a cam for something like 3.55 and put it in now expecting to do the rear end soon? I've been struggling to find a 83/4 and want to keep moving on the engine build. Thank you for help!
 
ft pistons, whose or whats your deck clerance
you have wedge heads but maybe no quench that makes a difference
how did you figure 9.5-10 and a lf point canmake a difference when you push the dynamic compression
all those comp cams are crap
those two thumpers are not recommended in their own cataog for 9.5:1 and higher
they are for stock 8:1 360's
what cam is in it now and what's your cranking compression?
new chain
 
It dose make a difference
if you put a cam optimised for 355 in it with the 2 series it will be a dog off the line but wil still run fine once you get rolling
think of it as a two speed with overdrive:)
 
Wyrmrider said:
ft pistons, whose or whats your deck clerance
you have wedge heads but maybe no quench that makes a difference
how did you figure 9.5-10 and a lf point canmake a difference when you push the dynamic compression
all those comp cams are crap
those two thumpers are not recommended in their own cataog for 9.5:1 and higher
they are for stock 8:1 360's
what cam is in it now and what's your cranking compression?
new chain
Click to expand...

They are Sealed Power 405P 4.03 pistons. They were inside the engine when I got it, but my machinist says they're still good and can just re-ring.
I took the heads off before sending it to the shop and used the summit calculator to measure CR and use the Summit calculator. My clearance was ~.106 (does that sound right? first time). I landed around ~9.2CR and I was thinking if the machinist had to deck the block I would fall somewhere between 9.5 and 10.

I don't actually know what cam is in it now, probably stock as it seemed and sounded mild. But it's at machine shop now so can't check!
On all cylinders I landed around 125-130PSI per.

Thank you Wymrider
 
Ben Ainsworth said:
Sounds like a wise move, does the gear ratio in the rear end greatly affect cam choice? Could I just select a cam for something like 3.55 and put it in now expecting to do the rear end soon? I've been struggling to find a 83/4 and want to keep moving on the engine build. Thank you for help!
Click to expand...

Talk to Cass. When I killed my 7 1/4 I ended up getting a Dana 4.10 gears and the Eaton trutrack, because it was in stock and the 8 3/4 wasn't. Also the Dana was only a Fist Full of Dollars more, cheap insurance. And dammit! It's my car and I wanted it.
Drivetrain :: Mopar 8 3/4"
 
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As recommended from Comp, the Comp XE268 would work well. That's what I run in my mild 360, and it goes.
Nice sounding cam as well. There are a lot of people very happy with this cam.
 
Wallace calculator. bore=4.03, stroke=3.578, head=63cc, piston=10cc (4 valve notch), gasket thickness= .041", gasket bore=4.15", piston below deck=.106" compression ratio is.... 8.17-1.
this creates a whole new outlook of what you have and what you can choose cam related!
 
Max1196 said:
Wallace calculator. bore=4.03, stroke=3.578, head=63cc, piston=10cc (4 valve notch), gasket thickness= .041", gasket bore=4.15", piston below deck=.106" compression ratio is.... 8.17-1.
this creates a whole new outlook of what you have and what you can choose cam related!
Click to expand...

Thank you Max1196,
I went back and checked my saved numbers and I had entered the stroke wrong! I also left 0 for pistons because theres not valve notches, but after googling it might be a +6. So thats 8.58 (or 9.08 without the +6).

I think I still want to get the block decked and bring the compression up to a 9.5 however?
 
Ottmundr said:
Talk to Cass. When I killed my 7 1/4 I ended up getting a Dana 4.10 gears and the Eaton trutrack, because it was in stock and the 8 3/4 wasn't. Also the Dana was only a Fist Full of Dollars more, cheap insurance. And dammit! It's my car and I wanted it.
Drivetrain :: Mopar 8 3/4"
Click to expand...
Cass was great help with my brakes so I'll certainly go to there for diff help. Thank you!
 
Ben Ainsworth said:
Thank you Max1196,
I went back and checked my saved numbers and I had entered the stroke wrong! I also left 0 for pistons because theres not valve notches, but after googling it might be a +6. So thats 8.58 (or 9.08 without the +6).

I think I still want to get the block decked and bring the compression up to a 9.5 however?
Click to expand...


Yes deck the block and yes get the CR up.
 
the sealed power pistons are dished-losing atleast 6cc of compression and with some block decking still will not give u quench. how much $ to deck block? maybe better to get taller pistons. no problem building engine now and swap rear gears later.
 
Marcohotrod said:
the sealed power pistons are dished-losing atleast 6cc of compression and with some block decking still will not give u quench. how much $ to deck block? maybe better to get taller pistons. no problem building engine now and swap rear gears later.
Click to expand...

Yea, I've started looking into it. Reckon I'm best off going with the Speed Pro H116CP, stock weight-ish... and leaving the deck as is. But that might set my CR quite a bit higher.
 
Forget about comp cams except the purple power and HL hyd (which are too big for you)
the Thumper is ok if your compression is way down there
get up near a real 9:1 and there are better choices
the Lunati 268 is much better than the comp 268 which slams the valves closed hard and makes tell tale noise this is true of all XE cams
post back when you get your compression figured out
if you can do pistons do so
otherwise the lunati 700 or 701 are where to start looking (not the 256 comp)
 
Ben Ainsworth said:
Yea, I've started looking into it. Reckon I'm best off going with the Speed Pro H116CP, stock weight-ish... and leaving the deck as is. But that might set my CR quite a bit higher.
Click to expand...
That is the piston I'm going with. I'm using a lunati voodoo 10200702 cam it's a mild street cam has a 220/226 @.50 duration and a .475 .494 lift. With those pistons and my heads at 65 cc I will be around 9.5 cr with a felpro blue gasket I can get more out of it with a mr gasket .028 gasket. For a street cruise car with iron heads 9.5 is plenty imo.

Screenshot_20200504-143402_Drive.jpg
 
are those the open or closed chamber edelbrocks
what's your deck clerance with those pistons
if you have the closed chamber edelbrocks go with a 0 deck piston even if you have to have a dish and balance
good choice on the cam
but quench makes more difference than the compression so if you can get closer to .030 with the mr gasket .028 do it
 
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