TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > Restoration facts, question and answer. > Part Numbers, AMC Parts ID and cross-references
  New Posts New Posts RSS Feed - AMC 69/70 Cam Specs
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

AMC 69/70 Cam Specs

 Post Reply Post Reply
Author
Message
badaboom View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Apr/07/2010
Location: CO, USA
Status: Offline
Points: 143
Post Options Post Options   Thanks (0) Thanks(0)   Quote badaboom Quote  Post ReplyReply Direct Link To This Post Topic: AMC 69/70 Cam Specs
    Posted: Apr/12/2015 at 8:33pm
I was wondering if someone would be nice enough to provide some factory cam specifications(lift - etc.) for the 1969 AMC 390 and the 1970 390 4 barrel carburetor motors.
Also anything for the performance package group 19 cams 69/70 and or component's. (or current production equivalents)
any reference links appreciated Thanks
Back to Top
Sonic Silver View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Nov/23/2011
Location: East Tennessee
Status: Offline
Points: 7902
Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Apr/12/2015 at 9:03pm
Measured at .050 lift:

1969-Early 1970 196 degrees 111 lobe centers .425 lift
Late 1970 207-208 degrees 114 lobe centers .457 lift
Group 19 224 duration 114 lobe center .477 lift

Edit: Sept 26 1969 is the cutoff engine build date between early and late 1970 cams.

Edited by Sonic Silver - Apr/12/2015 at 9:21pm
Back to Top
badaboom View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Apr/07/2010
Location: CO, USA
Status: Offline
Points: 143
Post Options Post Options   Thanks (0) Thanks(0)   Quote badaboom Quote  Post ReplyReply Direct Link To This Post Posted: Apr/12/2015 at 9:27pm
Thanks what is a good current production comparable cam like the Group 19 camshaft specs?
Back to Top
Sonic Silver View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Nov/23/2011
Location: East Tennessee
Status: Offline
Points: 7902
Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Apr/12/2015 at 10:12pm
Howards Camshaft has one that is similar , as does Sig Erson. In Erson's 2013 catalog, it is called a "Street Fighter Hydraulic" part number E710018. Their website is pbm-erson.com, but I don't find the cam listed there. You may have to call them. Howard's Camshafts also has that cam. It is pretty much just the old 350/350 or L82 Chevy grind. Good for higher compression engines, due to late closing intake timing. You can easily find cams that are more modern, and make more mid-range torque.
Back to Top
badaboom View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Apr/07/2010
Location: CO, USA
Status: Offline
Points: 143
Post Options Post Options   Thanks (0) Thanks(0)   Quote badaboom Quote  Post ReplyReply Direct Link To This Post Posted: Apr/12/2015 at 10:31pm
kinda checking the comp cam Magnum 10-203-4 270H seems pretty close a tad larger
Duration @ .050" Lift:      Int: .224 Exh: 224
Lobe separation: 110
Valve lift INT: 0.48 and Exh: 0.48

Edited by badaboom - Apr/13/2015 at 12:06am
Back to Top
Sonic Silver View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Nov/23/2011
Location: East Tennessee
Status: Offline
Points: 7902
Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Apr/13/2015 at 8:03am
Originally posted by badaboom badaboom wrote:

kinda checking the comp cam Magnum 10-203-4 270H seems pretty close a tad larger
Duration @ .050" Lift:      Int: .224 Exh: 224
Lobe separation: 110
Valve lift INT: 0.48 and Exh: 0.48
The difference is the lobe separation angle, and the fact that the Comp is ground 4 degrees advanced. The specs at .050 on the Comp should be:
IO: 6 BTDC
IC: 38 ABDC
EO: 46 BBDC
EC:-(2) ATDC

The 110 lobe center advances the intake numbers 4 degrees compared to the 114 lca, and retards the exhaust numbers 4 degrees compared to the 114. The same cam lobes on a 114 lca with a 4 degree advance would be:

IO: 2 BTDC
IC: 42 ABDC
EO: 50 BBDC
EC:-(6)ATDC

   I don't think that the Group 19 had a 4 degree advance as ground so figures would be:

IO:-(2) BTDC
IC: 46 ABDC
EO: 46 BBDC
EC:-(2) ATDC

Notice on the bottom 2 cams that the overlap is the same at-(4) degrees. Add the IO and EC numbers to get the degrees that both valves are open. The first cam on a 110 lca has +4 degrees overlap. The 110 lca has 8 degrees more overlap, and an intake closing that is 8 degrees sooner than the last cam.

   The first cam will fall off the power band quicker and have more mid range torque than the last cam, due to the earlier intake valve closing. It will also idle rougher due to the increased overlap.
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.109 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or