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Heads/Cam for 81
Thread Starter
Advanced
Joined: Oct 2023
Posts: 72
Likes: 22
From: Greeley, CO
Heads/Cam for 81
Hi all. My machine ship recommended these heads/cam for my 81. Bone stock now other than timing bumped to 13 degrees. Need headers too and am thinking Dougs longtubes? Thanks for any help you can give!
Heads- AFR 1001
Cam- Comp 12-432-8
Lifters- SUM-HT218-16
Cole
Heads- AFR 1001
Cam- Comp 12-432-8
Lifters- SUM-HT218-16
Cole
Pro
Joined: Aug 2009
Posts: 704
Likes: 503
From: Temple, TX
If you're truly "stock" and still have the CCC system on your car, that cam is going to cripple the system and your car. It's way too aggressive for the CCC system to function properly. If you have a standard, HEI and a non-computer-controlled carb, like a Holley or pre-'81 Quadrajet, it will be fine.
Those heads should put you in the area of ~9.0-9.2:1 compression, assuming you have stock pistons. That's still a bit on the low end of what a cam that size would probably want. The resident engine experts here will probably chime in on this. Also, which rear gear do you have? If it is the stock 2.87:1 that '81 4-speed cars came with, you're going to want to upgrade that too. A smaller duration roller cam may be the better way to go here. Don't forget about the cam button, wear plate or reinforced timing cover for the button, correct material distributor gear to match the new cam material, and new pushrods (measure!).
Those heads should put you in the area of ~9.0-9.2:1 compression, assuming you have stock pistons. That's still a bit on the low end of what a cam that size would probably want. The resident engine experts here will probably chime in on this. Also, which rear gear do you have? If it is the stock 2.87:1 that '81 4-speed cars came with, you're going to want to upgrade that too. A smaller duration roller cam may be the better way to go here. Don't forget about the cam button, wear plate or reinforced timing cover for the button, correct material distributor gear to match the new cam material, and new pushrods (measure!).
Pro
Joined: Aug 2009
Posts: 704
Likes: 503
From: Temple, TX
Careful on those gear sets. Our late C3's have the Dana 44 rear ends and they take a special size of gears to fit in the case. Not just any "Dana 44" gear set will work.
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Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
That is too much cam and too much head......195cc head is not a good choice for street small block in the sub-400hp range.....
Better choices are the Dart 180 Pro 1, The Trick Flow DH175 (175cc intake port, my personal choice, 60cc chamber for even more compression).....with this head you will be at 9.8 to 1 with a .028 #5746 Mahle head gasket.....
My choice of cam is this: Hydraulic Roller Camshaft; 1955 - 1998 Chevy 262-400 1500 to 5600 Howards Cams 111145-10 | Howards Cams
The above cam pulls HARD in a 350.....use a 2701 Performer EPS intake and a Holley Classic 650DP carb.......
Having a correctly curved distributor is important here......as is a free flowing exhaust with long tube headers.....
You can expect 420hp from this combo.....and with 3.36 gears a high 12 second time slip......on the stock short block......
You will pay more for my Cylinder head choices....but there is a reason for that......I can tell you that you will not find a nicer head than the Trick Flow......it's a premium piece......
Jebby
Better choices are the Dart 180 Pro 1, The Trick Flow DH175 (175cc intake port, my personal choice, 60cc chamber for even more compression).....with this head you will be at 9.8 to 1 with a .028 #5746 Mahle head gasket.....
My choice of cam is this: Hydraulic Roller Camshaft; 1955 - 1998 Chevy 262-400 1500 to 5600 Howards Cams 111145-10 | Howards Cams
The above cam pulls HARD in a 350.....use a 2701 Performer EPS intake and a Holley Classic 650DP carb.......
Having a correctly curved distributor is important here......as is a free flowing exhaust with long tube headers.....
You can expect 420hp from this combo.....and with 3.36 gears a high 12 second time slip......on the stock short block......
You will pay more for my Cylinder head choices....but there is a reason for that......I can tell you that you will not find a nicer head than the Trick Flow......it's a premium piece......
Jebby
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
You definitely need to learn about changing your ignition timing curve and setting timing based on total advance - not including vacuum advance. Setting your timing at idle is not the way to tune for performance.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Jebby
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Pro
Joined: Apr 2021
Posts: 571
Likes: 101
From: Texas
Too much cam. If it is a daily driver/cruiser, I would take it down to 224intake/230 exhaust or anything under a 276 comp cam. Suggest this or smaller in Roller cam:
Duration @ 0.006": 276° / 282° Duration @ 0.050": 224° / 230°
Duration @ 0.006": 276° / 282° Duration @ 0.050": 224° / 230°
Advanced
Joined: Dec 2022
Posts: 96
Likes: 20
Money no object
get cnc afr 195 steet heads and have afr knock them down to 60cc or more ,for you. They have a 1.9 min cross section which is about perfect for 6000rpm 350
If money is a object keep the cast heads you mentioned ,has the same min cross section as cnc head, but is a different port design with some core shift and valve job isn't blended to port well on some ports. Hence why it's cheaper with same good hardware as there good head. Little work it flows as good liitlr more work its better than cnc version. But not enough to justify the cost of paying someone to do it. You get what you pay for.
276/282 would work
depending on cam and shaving heads. Now piston to valve may become a issue . Which is usually the case when everything is getting close to where it needs to be
get cnc afr 195 steet heads and have afr knock them down to 60cc or more ,for you. They have a 1.9 min cross section which is about perfect for 6000rpm 350
If money is a object keep the cast heads you mentioned ,has the same min cross section as cnc head, but is a different port design with some core shift and valve job isn't blended to port well on some ports. Hence why it's cheaper with same good hardware as there good head. Little work it flows as good liitlr more work its better than cnc version. But not enough to justify the cost of paying someone to do it. You get what you pay for.
276/282 would work
depending on cam and shaving heads. Now piston to valve may become a issue . Which is usually the case when everything is getting close to where it needs to be
Thread Starter
Advanced
Joined: Oct 2023
Posts: 72
Likes: 22
From: Greeley, CO
