What Cam!
Thread Starter
Instructor
Joined: Jun 2006
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From: East Liverpool Ohio
What Cam!
I'm in the process of rebuilding my 74 350 l82 and I have no idea of what cam I should run. The guy that did the block and heads told me I should put a 480 lift cam in. I didn't ask him what cam he had in mind I just got my block and heads back and figured I could decide on a cam myself. But the more I read about it the more undecided I get.
The block was decked .010 and the heads were shaved .019. The heads are 882's with new springs. He said he had to change the springs because the stock springs wouldn't handle the lift.
So can someone tell me what my cr would be? I know that has alot to do with the cam selection.
Thanks for any help, Chip
The block was decked .010 and the heads were shaved .019. The heads are 882's with new springs. He said he had to change the springs because the stock springs wouldn't handle the lift.
So can someone tell me what my cr would be? I know that has alot to do with the cam selection.
Thanks for any help, Chip
Le Mans Master
Joined: Apr 2007
Posts: 7,353
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From: Graceland in a Not Correctly Restored Stingray
Your builder should know the final CR, post milling. Don't be afraid to ask him questions.
And yes, CR has a lot to do with cam selection. Here's a link to a site that will help explain the relationship...
http://www.empirenet.com/pkelley2/DynamicCR.html
It's far from the only consideration, but before making your selection if you'll download the DCR calculator and play around with it some you'll have a better idea of whats going on.
And yes, CR has a lot to do with cam selection. Here's a link to a site that will help explain the relationship...
http://www.empirenet.com/pkelley2/DynamicCR.html
It's far from the only consideration, but before making your selection if you'll download the DCR calculator and play around with it some you'll have a better idea of whats going on.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
If you're putting old OE L82 pistons back in (forged flattop w/ single trough) ... they should sit about 0.025" down in hole of stock block (down 0.015" in yours) and have about -3.4cc dome volume. If 882 heads were 76cc ... then cut 0.019" ... they're probably about 72.5-73cc now. So ... stock L82 pistons, deck cut 0.010", heads milled 0.019" using thin shim felpro 1094 gasket (3.2cc) ... should yield about 9.7:1 scr. Lotsa ifs ... who knows what gaskets & pistons you have ... we can only guess.
handy accurate scr calculator from TRW/Federal Mogul
http://www.21cgt.com/FMWebCatalog/frmConversion4.aspx
compression, transmission, rear gear & how/where you drive are required when figuring what cam to use.
handy accurate scr calculator from TRW/Federal Mogul
http://www.21cgt.com/FMWebCatalog/frmConversion4.aspx
compression, transmission, rear gear & how/where you drive are required when figuring what cam to use.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Le Mans Master
Joined: Apr 2006
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The minumum piston to head clearance recomended is .035,
with .010 cut off your block find out how far the pistons are
down for sure before you buy a gasket.
with .010 cut off your block find out how far the pistons are
down for sure before you buy a gasket.
Last edited by Little Mouse; Nov 13, 2007 at 06:09 AM.
Thread Starter
Instructor
Joined: Jun 2006
Posts: 166
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From: East Liverpool Ohio
Thanks for the replies. It will have KB flat top pistons and it is bored 30 over. I haven't bought a head gasket yet because I know I need to keep the quench between .035 & .045. I plan on just driving the car locally. I might occasionally drive it to work about 25 miles. I just want it to be snappy, if you know what I mean. It should make a little over 300hp. That should be enough to get me in trouble! I think I'm going to run a performer intake. I've been looking at the permastar. Will the air gap fit under my hood? That's the intake I would like to run.
Thanks again for the help. This is a great site!!
Thanks again for the help. This is a great site!!
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
It will have KB flat top pistons and it is bored 30 over. I haven't bought a head gasket yet because I know I need to keep the quench between .035 & .045. I plan on just driving the car locally. I might occasionally drive it to work about 25 miles. I just want it to be snappy, if you know what I mean. It should make a little over 300hp. That should be enough to get me in trouble! I think I'm going to run a performer intake. I've been looking at the permastar. Will the air gap fit under my hood?
Safety Car
Joined: Oct 2000
Posts: 3,593
Likes: 103
From: Southern Indiana
I thought the question was "what cam" not pistons?
A Comp Cams Magnum grind with 470 lift/270 duration, 110 lobe separation is about as big as you want to go with a stock torque converter.
A Comp Cams Magnum grind with 470 lift/270 duration, 110 lobe separation is about as big as you want to go with a stock torque converter.
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Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
His static compression ratio is/was not known ... nor was his piston. Many folks won't a recommend cam without first knowing static compression ratio. I did suggest a cam, but only after I'd speced out an scr. K1103 will work w/ even a stock converter & high rear gear.
Le Mans Master
Joined: Apr 2007
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From: Graceland in a Not Correctly Restored Stingray
Thread Starter
Instructor
Joined: Jun 2006
Posts: 166
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From: East Liverpool Ohio
Thanks guys. I guess I should have said what pistons I was going to use. I didn't think they would make that much difference. Also I have a 4 speed with 370 gears.
skunkworks I was only going to run KB pistons because they were the only aftermarket pistons I knew of. It's been about 35 years since I built an engine. I actually knew about Sealed Power but wasn't sure of the quality.
I have the block with the cam bearings and softplugs installed and that's it. I'm going to need all the bearing, oil pump, cam, timing set, and of course pistons and rings. I guess someone would make a kit for this.
skunkworks I was only going to run KB pistons because they were the only aftermarket pistons I knew of. It's been about 35 years since I built an engine. I actually knew about Sealed Power but wasn't sure of the quality.
I have the block with the cam bearings and softplugs installed and that's it. I'm going to need all the bearing, oil pump, cam, timing set, and of course pistons and rings. I guess someone would make a kit for this.