You got it!
.480/230 cam in an 8.5 CR 360?
- Thread starter fshd4it
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junkyardhero
Well-Known Member
iffin' you're gonna run that cam, i'd advance it as suggested. but as others have noted with that combo: low compression, blah stall, no gear and heavy car-- you've got a recipe for dog water. though, it'd probably run pretty good at highway speed.
there's nothing inherently wrong with that cam, but if you're looking to swap it i personally think that there's many other, more modern grinds out there that are much more suitable to the task at hand.
there's nothing inherently wrong with that cam, but if you're looking to swap it i personally think that there's many other, more modern grinds out there that are much more suitable to the task at hand.
If you REALLY want a first hand understanding, here's what you do. With the engine assembled and timing cover off. Rig up some sort of starter mount. A manual bellhousing with a flywheel will work. Degree the cam straight up at 109. That's even with the lobe center. Now, get a compression gauge and measure cranking pressure in #1 and record it. Now advance the cam timing down to 100 ICL and get a cylinder pressure reading there. You will see the difference for yourself. It will not be accurate unless you degree the cam to 109 FIRST.
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I don't think it'll be "that bad". I recollect a LOT of us ran big hydraulic cams straight up in low compression motors when we were kids and didn't know any better. They sounded great in the high school parkin lot. They pulled good too startin about 4k. LOL
junkyardhero
Well-Known Member
it's survivorship bias.
also you old farts can't remember what you had for breakfast let alone fiddy years ago!
(i keed, i keed)
Good. So that means when I get my CR sorted, I'll be back to talk more about how much I should bump the cam forward. However it works, I'll shoot for at least 9:1, or more if that's how the parts work out. And acquire an adjustable timing chain set, as this one's not.
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Hush up fool. lolit's survivorship bias.
also you old farts can't remember what you had for breakfast let alone fiddy years ago!
(i keed, i keed)
At 9:1......a MEASURED 9:1 and not "bench racin" 9:1, I'd go 4 degrees advanced. That would be 105 ICL.
Those would be a No Brainer for me. Deep port the flanges of the performer intake to match a set of 1243 Fel-Pro gaskets (theyr'e a performance intake gasket for a 273/318, but they match a J head's intake ports well), and install the cam on a 105 ICL. The compression boost and low lift flow with 2.02 J heads would work pretty well. It would certainly work some better with the high gears and somewhat tight stall.
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When you are at 8.5:1 with a cam designed for 10:1 CR; more compression will definitely help. And it will help throughout the rpm range. Some modifications do not do this....
Once you increase the CR, I would advance the cam to 104-105 ICL. This increases low end tq by closing the int valve earlier & trapping more air.
You will need to check valve to piston clearance before doing these mods. I doubt there would be a problem, but best to check.
Once you increase the CR, I would advance the cam to 104-105 ICL. This increases low end tq by closing the int valve earlier & trapping more air.
You will need to check valve to piston clearance before doing these mods. I doubt there would be a problem, but best to check.
BSB67
Well-Known Member
Agree with most posts, increase CR, advance cam.
But, at this point maybe consider a regrind of the cam and resurface of the lifters. That cam would probably work as a good core to grind something better suited for your application. I get that budget matters but maybe price it out.
But, at this point maybe consider a regrind of the cam and resurface of the lifters. That cam would probably work as a good core to grind something better suited for your application. I get that budget matters but maybe price it out.
That's almost exactly what I did, but I made templates of the ports instead of using a gasket. It was a cheap manifold I had on hand, so I used it, while understanding it's not much (if any) better than a factory cast-iron one. Chances are good I'll swap it out for a Weiand 8002 I've got on the shelf.
PRH
Well-Known Member
If it’s in the budget I’d opt for a cam that’s a closer match for the mild gears and converter.
Something more like a 268 cam.
Something more like a 268 cam.
It's not so much the budget, it's the fact that I hate breaking in a cam. I hate the thought, even, of breaking in a cam. So much that my next motor (if I have need for one) will be the '89 roller 360 under the bench. I know that makes me stubborn, even maybe coming across as argumentative (or unappreciative, which I'm certainly not), and for that I apologize. Remember, you can always tell a Norwegian, but you can't tell him much... Though I've put less than 50 miles on the car since this motor went in, when it was still in the '79 3/4 ton it came from, in original rebuilt form, I ran the snot outta that thing. And since the cam and lifters look fine...
Then run what you have and advance it. It will run fine. Stop thinkin about it and just do it.
I know, i know, but it's the thinkin' that always gets me in the end. Last night I retrieved the original 596 heads (I mistakenly said 587s before, I was wrong) from this motor. Measuring one of them, I've got 64, 65, 65.5, and 67cc, end to end. Looks like the head's not flat. But I think it'll give me the CR I'm looking for. I know I've seen a post about how many thousands to mill off for a cc, but I haven't been able to find it again. I'd like to get them cut flat, and having a # to give the machinist would be nice. Any idea what it might be?
Then run the cam you have and plan your roller block build.
"About" .0067 = 1cc. But consider this before you do "all that". Going one full point up in compression only nets you about a 3% power difference, all things equal. IMO, totally not worth it. But knock yourself out. You're reading far too many magazines and forums that insist you have close to 10:1 or you'll have a turd. It's just not true, but you're hell bent, so go for it.
Newbomb Turk
Well-Known Member
Buy the correct cam. I’m not in the advance the **** out of it because the cam is too big.
If you are advancing the cam more than a couple of degrees from having the overlap triangle centered it might run better but it’s hurting power.
No compression and 230 at .050 is not good.
If you are advancing the cam more than a couple of degrees from having the overlap triangle centered it might run better but it’s hurting power.
No compression and 230 at .050 is not good.
Maybe not optimal, but millions of builds have been built that way and turn out fine. Not everybody is looking to wring every single bit or power out of one. Some people need to use what they have.
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