Tweet
Can anyone provide the specs and part number for a correct 67/435HP camshaft and are there any differences in the various suppliers camshafts in terms of quality and cost. Thanks as always.
-
-
Re: 67/435 camshaft
Hi Rick --- The correct (original) GM part# is 3863143, and generally it was the street mechanical cam used on L78, L72, L71 and LS6 Corvettes. The '67 GM specs are: lift = 0.520" (intake and exhaust); duration = 316° int./302°exh. According to Alan Colvin's book, the lift and duration were different in '65 and the duration (only) was different in '66 [same part # though]. Then, in '67 and '68 he quotes the part # as 3904362, but reverts to the old # in '69, with the same spec's, as I first mentioned above. Usually GM changes part # for the slightest design change [maybe Joe L. can add something]. Also, remember that '67 and up uses the non-grooved rear journal.
Other sources quote lift at 0.500" (both lobes), valve timing: inlet opens 40° before top-dead-centre, closes 86°after bottom-D-C. Exhaust opens 88° before bottom-D-C, closes 38° after top-D-C. Duration for both intake and exhaust is 306° with mech lifters 0.015" off the base circle.
P.S. with the price of gas in Montréal, I would have thought you'd be looking for an ECONOMY grind. ---- Wayne -
Re: 67/435 camshaft
Hi Rick --- The correct (original) GM part# is 3863143, and generally it was the street mechanical cam used on L78, L72, L71 and LS6 Corvettes. The '67 GM specs are: lift = 0.520" (intake and exhaust); duration = 316° int./302°exh. According to Alan Colvin's book, the lift and duration were different in '65 and the duration (only) was different in '66 [same part # though]. Then, in '67 and '68 he quotes the part # as 3904362, but reverts to the old # in '69, with the same spec's, as I first mentioned above. Usually GM changes part # for the slightest design change [maybe Joe L. can add something]. Also, remember that '67 and up uses the non-grooved rear journal.
Other sources quote lift at 0.500" (both lobes), valve timing: inlet opens 40° before top-dead-centre, closes 86°after bottom-D-C. Exhaust opens 88° before bottom-D-C, closes 38° after top-D-C. Duration for both intake and exhaust is 306° with mech lifters 0.015" off the base circle.
P.S. with the price of gas in Montréal, I would have thought you'd be looking for an ECONOMY grind. ---- WayneComment
-
Re: 67/435 camshaft
The latest issue of CHEVY BUYER GUIDE has all the big block cam shaft spec's except the the lobe center seperation angle and lift at .050 tappet lift. This more complete information is available from COMP CAMS OR CRANE CAMS since they both make a "blue printed" copy of the originals.Comment
-
Re: 67/435 camshaft
The latest issue of CHEVY BUYER GUIDE has all the big block cam shaft spec's except the the lobe center seperation angle and lift at .050 tappet lift. This more complete information is available from COMP CAMS OR CRANE CAMS since they both make a "blue printed" copy of the originals.Comment
-
Re: 67/435 camshaft
Rick and Wayne-----
The original part number for the camshaft was, indeed, GM # 3863143. This part number was replaced by GM #3904362 sometime after 1984. However, it is possible that the 3904362 camshaft was also used during 1967 and 1968----the 3904362 is very likely a 1967-issued part number. Actually, I 've always wondered about this myself, but never researched it. I'll try to remember to do so.
In any event, the 3863143 and 3904362 camshafts DO NOT HAVE identical specifications, although they are very similar, as I recall. I don't have reference material on them handy at the moment.
The 3904362 camshaft is still available from GM and carries a list price of $185.77. The 3863143 camshaft is available in reproduction. If it were me, I'd buy the reproduction available from Crane Cams.In Appreciation of John HinckleyComment
-
Re: 67/435 camshaft
Rick and Wayne-----
The original part number for the camshaft was, indeed, GM # 3863143. This part number was replaced by GM #3904362 sometime after 1984. However, it is possible that the 3904362 camshaft was also used during 1967 and 1968----the 3904362 is very likely a 1967-issued part number. Actually, I 've always wondered about this myself, but never researched it. I'll try to remember to do so.
In any event, the 3863143 and 3904362 camshafts DO NOT HAVE identical specifications, although they are very similar, as I recall. I don't have reference material on them handy at the moment.
The 3904362 camshaft is still available from GM and carries a list price of $185.77. The 3863143 camshaft is available in reproduction. If it were me, I'd buy the reproduction available from Crane Cams.In Appreciation of John HinckleyComment
-
Re: 67/435 camshaft
Rick, I used the Comp Cam factory replacement for the GM 3863143 when I had the 425 hp motor in my 66 rebuilt to factory spec's. When the motor was run on the dyno it came in at 447 hp which is about the original GM published rating (450 hp)so I would conclude the cam is at least close to factory original. So far all seems OK with the cam. Hope this helps. MarkComment
-
Re: 67/435 camshaft
Rick, I used the Comp Cam factory replacement for the GM 3863143 when I had the 425 hp motor in my 66 rebuilt to factory spec's. When the motor was run on the dyno it came in at 447 hp which is about the original GM published rating (450 hp)so I would conclude the cam is at least close to factory original. So far all seems OK with the cam. Hope this helps. MarkComment
-
Re: 67/435 camshaft
Thanks guys. As usual you guys are fantastic!!! The supplier here in Montreal has the 3863143 cam from Crane. The Crane part number is: 969961. However the specs they give me do not jive with the specs mentioned here. The specs I get from the supplier are:242D@.050 and.520 L As you can see the lift is the same but the duration is not. Can anyone clarify? Thanks as always.Comment
-
Re: 67/435 camshaft
Thanks guys. As usual you guys are fantastic!!! The supplier here in Montreal has the 3863143 cam from Crane. The Crane part number is: 969961. However the specs they give me do not jive with the specs mentioned here. The specs I get from the supplier are:242D@.050 and.520 L As you can see the lift is the same but the duration is not. Can anyone clarify? Thanks as always.Comment
-
Re: 67/435 camshaft
The mfg. gave you duration at .050, the General lists duration at gross lift. The spec @.050 is a more accurate measurement of the cam's duration than the spec at gross lift.Comment
-
Re: 67/435 camshaft
The mfg. gave you duration at .050, the General lists duration at gross lift. The spec @.050 is a more accurate measurement of the cam's duration than the spec at gross lift.Comment
Comment