.480/230 cam in an 8.5 CR 360?

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fshd4it

fshd4it

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I just tore down a 360 I've had for 20+ years, zero to low-mile rebuild when I got it, and very little use since. The cam looks to be an older Lunati Bracket Master 2, (as all my timing events match), w/ .480" lift, 230 deg duration (@ .050), and a 109 LSA. As it's installed straight up, centerline is 109 deg, but Lunati's cam card says to install 2 deg advanced. It's got 1.88 J heads (70cc), Speed Pro/Sealed Power H405P pistons, and 8553 head gaskets, for a CR of 8.5-1. I've driven this thing so little, I don't really know how it acts. It's for a '65 Belvedere, 727 with a 2,000 +/- converter, and 3.23 rear... car will just be a pump gas driver. Is there anything to be gained by bumping the compression up to 9-1 (which they call for)? Does the cam really need it? I'll have the heads cut a bit, if popular consensus says to. TIA, Karlin.

Screenshot_20240918-113050_Gallery.jpg
 
I'd install that cam at least down to 103 ICL and might go as far as 100.
 
fshd4it said:
Educate me on changing a cam's ICL, please. What does it do/change?
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Intake center line. That's where the cam installs. The lobe separation is 109. If that was mine, I would install it down around 102, or even 100, which would be 9 degrees advanced. When Lunati gives an installed place, in this case 107, which is 2 degrees advanced, they aren't assuming someone will put the cam in an engine with only 8.5 compression.
 
Not the cam I'd use in a heavy B body with a 3:23 gear, but if I WAS gonna use it, I'd do like RustyRatRod suggested
 
I get the process of physically changing the relation between the cam and crank, but I've never really understood the reasoning behind it. Advancing the cam introduces the air/fuel and dumps the spent gasses earlier (correct?), but what are the effects? I've seen it mentioned enough to guess it's quite application specific?
 
You can never go wrong with bumping your compression ratio up a bit, but you have to check it by cc the combustion chamber and piston face at TDC to know what it really is.
 
fshd4it said:
Educate me on changing a cam's ICL, please. What does it do/change?
Click to expand...


When you advance the cam, you close the intake earlier, meaning the volume in the cylinder is greater creating more cranking compression/pressure in the cylinder vs a straight up 109 centerline.

We did this all the time with the 480-484-508 hyd purple cams, cut on a 108, install at 100, makes a huge difference getting out of the hole.
 
abdywgn said:
boost in compression and valve lift with magnum heads
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I've got a set of them, but they need to be redone. Then either drilled, or buy a new manifold. As well as new pushrods, springs, and whatnot. Thought about it, but not for this motor.
 
ch1ll said:
You can never go wrong with bumping your compression ratio up a bit, but you have to check it by cc the combustion chamber and piston face at TDC to know what it really is.
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I cc'd everything. Bought a burrette and all the other goodies. I like tools, even if I have to learn how to use them.
 
I have a few other sets of heads, including a set of 2.02 J castings that measured 62+/- cc. So that would bump my CR, I just don't know if I need the bigger valves. Plan was to use them on another engine.
 
It's a young rebuild so why did you tear it down...

Advance the cam, throw as much initial timing that it will take, a duel plane int. would be a must and the shortest tires that still look decent.

At least it will drivable and sure sound good. :)
 
fshd4it said:
I get the process of physically changing the relation between the cam and crank, but I've never really understood the reasoning behind it. Advancing the cam introduces the air/fuel and dumps the spent gasses earlier (correct?), but what are the effects? I've seen it mentioned enough to guess it's quite application specific?
Click to expand...
@ajforms
 
fshd4it said:
I get the process of physically changing the relation between the cam and crank, but I've never really understood the reasoning behind it. Advancing the cam introduces the air/fuel and dumps the spent gasses earlier (correct?), but what are the effects? I've seen it mentioned enough to guess it's quite application specific?
Click to expand...
@AJ/FormS
 
OldmanRick said:
It's a young rebuild so why did you tear it down...

Advance the cam, throw as much initial timing that it will take, a duel plane int. would be a must and the shortest tires that still look decent.

At least it will drivable and sure sound good. :)
Click to expand...
I bought a truck with this motor in it. Pulled it out around '03, stole the rebuilt 587 heads for another car, then ended up putting some well-used 915s on it. Stuck it in my '65 around 2010, without ever looking at the short block. I wanted to know what i was dealing with, and I have too much spare time right now...
I'm running 295 50/15s, and it has a performer intake (for now) with a 600 Edelbrock AFB. And yes, it does sound pretty decent.
 
No way Jose! Total lost cause. 8.5 to 1, heavy car, stockish convertor 3.23's. You lose. Put in a stock 340 cam at best. Advance it 2 - 4 degrees. Ran that 230 cam 50 years ago. But it does sound good.
 
crackedback said:
When you advance the cam, you close the intake earlier, meaning the volume in the cylinder is greater creating more cranking compression/pressure in the cylinder vs a straight up 109 centerline.

We did this all the time with the 480-484-508 hyd purple cams, cut on a 108, install at 100, makes a huge difference getting out of the hole.
Click to expand...
You'll not get a better or simpler answer than this. ^^^^^^
 
RustyRatRod said:
You'll not get a better or simpler answer than this. ^^^^^^
Click to expand...
So, if I understand, it would also be beneficial with a higher CR (if I go there), just not advanced as much? At least Lunati's 2 degrees, maybe more?
 
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