GM cam identification

[G B.]

I have a GM cam cast with the number 6930X between two of the lobes. Can anyone i.d. this cam for me based on this number?

This cam appears to be a mild hydraulic grind for a small block, but I want to be sure it's nothing rare before I throw it away.

[Tracy C.]

Re: GM cam identification

Jerry,

If you don't get any responce on the application, Rather than pitching it why don't you put it in a box with an old leaf spring and ship it to me using Fedex with a declared value of $500.

Better than the lottery...

tc

[Tracy C.]

Re: GM cam identification

Jerry,

If you don't get any responce on the application, Rather than pitching it why don't you put it in a box with an old leaf spring and ship it to me using Fedex with a declared value of $500.

Better than the lottery...

tc

[Duke W.]

Re: GM cam identification

That is a '67 to '80 base engine camshaft, informally known as the "300 HP cam", and it was used on most 327 and 350 configurations of that era. The full part number for the FINISHED CAMSHAFT (NOT the casting number) is 3896930.

GM camshafts are only sold as "assemblies", which includes the camshaft and dowel pin. The part number for this "camshaft assembly" is 3896929, and it has been superseded by 14088839.

In this case the finished camshaft number and camshaft/pin assembly number are sequential. This is not always the case, but they are usually fairly close in sequence.

I'm not sure what the "X" means.

Duke

[Duke W.]

Re: GM cam identification

That is a '67 to '80 base engine camshaft, informally known as the "300 HP cam", and it was used on most 327 and 350 configurations of that era. The full part number for the FINISHED CAMSHAFT (NOT the casting number) is 3896930.

GM camshafts are only sold as "assemblies", which includes the camshaft and dowel pin. The part number for this "camshaft assembly" is 3896929, and it has been superseded by 14088839.

In this case the finished camshaft number and camshaft/pin assembly number are sequential. This is not always the case, but they are usually fairly close in sequence.

I'm not sure what the "X" means.

Duke

[Patrick H.]

Re: GM cam identification

If you determine it's unused and "common enough" to throw away, please let me know. I'd be interested.

Patrick

[Patrick H.]

Re: GM cam identification

If you determine it's unused and "common enough" to throw away, please let me know. I'd be interested.

Patrick

[Joe L.]

Re: GM cam identification

Patrick-----

Once-upon-a-time these were quite common. It's "descendants", the GM #14060651 and GM #14088839, are still quite common today. They're also probably the best street cams that GM ever cam up with for the small block. They're not for the guys that like "high winders" or the cache of cams with pseudonyms like "30-30", "Duntov", or "LT-1". But, they are for the guys that like plenty of low-end torque, GREAT street manners, and an all-around enjoyable-to-drive car.

[Joe L.]

Re: GM cam identification

Patrick-----

Once-upon-a-time these were quite common. It's "descendants", the GM #14060651 and GM #14088839, are still quite common today. They're also probably the best street cams that GM ever cam up with for the small block. They're not for the guys that like "high winders" or the cache of cams with pseudonyms like "30-30", "Duntov", or "LT-1". But, they are for the guys that like plenty of low-end torque, GREAT street manners, and an all-around enjoyable-to-drive car.

[Verne Frantz]

Re: GM cam identification

Same cam that was used to bump the 170hp 283 to 195hp in '63. (and the 250hp 327) All the same cam.

[Verne Frantz]

Re: GM cam identification

Same cam that was used to bump the 170hp 283 to 195hp in '63. (and the 250hp 327) All the same cam.

[G B.]

Thank you all for the help.

Patrick, I have no use for this cam, but it isn't new. I don't remember exactly where I got it. I've kept it for about 20 years because it had little wear. You can have the thing if you really want it. However, if you'd prefer to buy a new cam, I understand.

I'm getting organized to conduct the "Beat Margaret to the City Dump" Sale early next year. I'm going to clean out the shop and get rid of all my extra parts, spare junk, and unfinished projects. I won't need all this crap during the next twenty years, and I'm damn sure tired of tripping over it while I try to work.

[G B.]

Thank you all for the help.

Patrick, I have no use for this cam, but it isn't new. I don't remember exactly where I got it. I've kept it for about 20 years because it had little wear. You can have the thing if you really want it. However, if you'd prefer to buy a new cam, I understand.

I'm getting organized to conduct the "Beat Margaret to the City Dump" Sale early next year. I'm going to clean out the shop and get rid of all my extra parts, spare junk, and unfinished projects. I won't need all this crap during the next twenty years, and I'm damn sure tired of tripping over it while I try to work.

[Duke W.]

Re: GM cam identification

That's not correct. The 3896929 did not enter production until the 1967 model year. It replaced the 3733431 "assembly", which is finished camshaft 3732798, which is also the "ID" number on the cam. This cam dates back to 1957 and was used on virtually all SBs until 1967 other than mechanical lifter engines and the L-79.

The 929 has slightly longer exhaust than inlet duration and is phased slightly earlier in recognition of the relatively restrictive exhaust ports on 461 and later "big port" heads compared to the earlier small port/valve 283 type heads.

The 929 also has milder dynamics, and it or its successors are the logical replacement for pre-'66 engines that still have the early cam.

On a 300 HP configuration, whilch makes an honest 225 SAE net HP at 4000-4500 and is all done by 5000, pocket porting the heads and retarding this cam 4 degrees will increase SAE net HP to about 265 and increase the useable rev range to 5500+.

The only other cam I would recommend is one of my own design that increases net HP to about 300 with massaged heads and useable revs to over 6000 with no loss of the typical smooth 500@17" idle characteristics, though there is some loss of low end torque, and I would not recommend it for Powerglide.

Duke

[Duke W.]

Re: GM cam identification

That's not correct. The 3896929 did not enter production until the 1967 model year. It replaced the 3733431 "assembly", which is finished camshaft 3732798, which is also the "ID" number on the cam. This cam dates back to 1957 and was used on virtually all SBs until 1967 other than mechanical lifter engines and the L-79.

The 929 has slightly longer exhaust than inlet duration and is phased slightly earlier in recognition of the relatively restrictive exhaust ports on 461 and later "big port" heads compared to the earlier small port/valve 283 type heads.

The 929 also has milder dynamics, and it or its successors are the logical replacement for pre-'66 engines that still have the early cam.

On a 300 HP configuration, whilch makes an honest 225 SAE net HP at 4000-4500 and is all done by 5000, pocket porting the heads and retarding this cam 4 degrees will increase SAE net HP to about 265 and increase the useable rev range to 5500+.

The only other cam I would recommend is one of my own design that increases net HP to about 300 with massaged heads and useable revs to over 6000 with no loss of the typical smooth 500@17" idle characteristics, though there is some loss of low end torque, and I would not recommend it for Powerglide.

Duke