1969 L-46 camshaft

[Kenneth G.]

Hello all,

Was reading an article in Vette magazine and one of the writers stated that an L-82 cam and an L-46 cam were almost identical in their configuration. I found this hard to believe as my 69 produces 350hp whereas a78L-82 produces 210hp or so.I know there is a difference in cylinder heads, compression etc but still makes me wonder.This got me to wondering so i dug up my cam spec sheet for the Crane Blueprinted Cam that i had installed in my 69 350 L-46 (motor hasnt been run yet, still in resto process).I selected the "replacement for factory 350hp 327c.i." bluprinted cam. Will this cam run just as effectively and produce 350 hp in a 350 as in a 327 or is there really no difference? My motor configuration is all stock (11:1 comp, roch carb.,orig intake etc).The specs on the cam I had installed are: 447 lift on intake and exhaust and the duration (at.050)is 222 degrees intake and exhaust. Is this close to the original L-46 cam??At the top of the spec cam sheet it says "Grind number 3863151" and this appeared to me to be possibly a referance to a GM number.Any body have a clue what specific cam this refers to?? Basically if anyone could advise me if this was a good choice for a cam or did i choose the wrong one .

Kenny-owner of a viginal L46 with questionable cam

[Paul Young]

Re: 1969 L-46 camshaft

The 3151 is one of my favorite cam grinds. It is the GM 327/350 horse cam and combines a good torque and power range for street driving. I have used this cam in motors for years but only in the 327 application. It may have a milder idle in the 350 but should be starting to make power at about 2500 RPM. I think that you have made a good choice.

[Paul Young]

Re: 1969 L-46 camshaft

The 3151 is one of my favorite cam grinds. It is the GM 327/350 horse cam and combines a good torque and power range for street driving. I have used this cam in motors for years but only in the 327 application. It may have a milder idle in the 350 but should be starting to make power at about 2500 RPM. I think that you have made a good choice.

[Jim Mitchell]

Re: 1969 L-46 camshaft

Kenny,

The "151" cam is the 350 HP 327 cam. It is an excellent performer. I ran one for several years in my '69 El Camino which I used to tow a '66 Chevelle to the drags. I had good pulling power throughout my driving range. The El Camino began life as a 300 horsepower 350 with Muncie 2-speed. The only engine modification was the "151" cam. Idle with the 350 C.I. motor is a little smoother than in a 327, but there is still a definite lope to the motor.

I have used this same grind cam in motors from 283 C.I. up to 350 C.I. and am currently building another 283 which will have this cam. As a side note, noted Pro Stock engine builders Reher and Morrison used this same cam in their Chevy pick-up/tow vehicle when they were racing a B-Gas Corvette years ago and they loved the cam.

[Jim Mitchell]

Re: 1969 L-46 camshaft

Kenny,

The "151" cam is the 350 HP 327 cam. It is an excellent performer. I ran one for several years in my '69 El Camino which I used to tow a '66 Chevelle to the drags. I had good pulling power throughout my driving range. The El Camino began life as a 300 horsepower 350 with Muncie 2-speed. The only engine modification was the "151" cam. Idle with the 350 C.I. motor is a little smoother than in a 327, but there is still a definite lope to the motor.

I have used this same grind cam in motors from 283 C.I. up to 350 C.I. and am currently building another 283 which will have this cam. As a side note, noted Pro Stock engine builders Reher and Morrison used this same cam in their Chevy pick-up/tow vehicle when they were racing a B-Gas Corvette years ago and they loved the cam.

[Joe L.]

Re: 1969 L-46 camshaft

Kenny----

The 69-70 L-46 and 73-80 L-82 camshafts are, indeed, the same. That camshaft is GM part number 3896962. 1965-1968 L-79 (327 cid 350 hp)engines used a different camshaft, GM #3863151. These camshafts have similar, but not identical, specifications. Personally, I feel that the '962' camshaft is better for 350+ cid engines and the '151' camshaft is best for 327 cid or smaller engines. Chevrolet engineers apparently did, too. Incidentally, both camshafts are still available from GM and both carry a current list price of $168.40.

[Joe L.]

Re: 1969 L-46 camshaft

Kenny----

The 69-70 L-46 and 73-80 L-82 camshafts are, indeed, the same. That camshaft is GM part number 3896962. 1965-1968 L-79 (327 cid 350 hp)engines used a different camshaft, GM #3863151. These camshafts have similar, but not identical, specifications. Personally, I feel that the '962' camshaft is better for 350+ cid engines and the '151' camshaft is best for 327 cid or smaller engines. Chevrolet engineers apparently did, too. Incidentally, both camshafts are still available from GM and both carry a current list price of $168.40.

[Doug Flaten]

Re: 1969 L-46 camshaft

Regarding the horsepower comparison of 350 hp vs 210 hp, you are right in that the similar engines would not be that far apart in HP rating. But youu are probably forgeting that net horsepower ratings are used on the later engines.

[Doug Flaten]

Re: 1969 L-46 camshaft

Regarding the horsepower comparison of 350 hp vs 210 hp, you are right in that the similar engines would not be that far apart in HP rating. But youu are probably forgeting that net horsepower ratings are used on the later engines.

[Wayne M.]

Re: 1969 L-46 camshaft

Kenny --- as you asked about the spec's between the #3863151 and the #3896962 (L46 - '69 & '70; L82 - '73 up) let me post what was on a GM cam spec sheet which was given to me by a parts man in the mid-'70's.

As you say the lift (zero lash) is 0.447" for both intake and exhaust lobes. The duration is 342° for both on the GM sheet I have, with overlap of 114°. It was used on '65 to '68 327 engines of 325 and 350 hp configurations.

The factory L46 cam has 0.450" intake and 0.460" exhaust lifts (zero lash) with 346° duration on intake, 340° on exhaust; overlap is also 114°. As you can see, the cams are VERY similar.

I'm of the same opinion as Joe -- the L46 cam would probably be marginally better in the 350 cube motor. Caution: don't use the GM factory spec's for duration to compare with your repro, as GM cam timing figures are "out to lunch", and should only be used to show the difference between the 2 factory cams. The "effective" duration you show is probably a more accurate figure for your 3151 repro AND the factory original cams.

[Wayne M.]

Re: 1969 L-46 camshaft

Kenny --- as you asked about the spec's between the #3863151 and the #3896962 (L46 - '69 & '70; L82 - '73 up) let me post what was on a GM cam spec sheet which was given to me by a parts man in the mid-'70's.

As you say the lift (zero lash) is 0.447" for both intake and exhaust lobes. The duration is 342° for both on the GM sheet I have, with overlap of 114°. It was used on '65 to '68 327 engines of 325 and 350 hp configurations.

The factory L46 cam has 0.450" intake and 0.460" exhaust lifts (zero lash) with 346° duration on intake, 340° on exhaust; overlap is also 114°. As you can see, the cams are VERY similar.

I'm of the same opinion as Joe -- the L46 cam would probably be marginally better in the 350 cube motor. Caution: don't use the GM factory spec's for duration to compare with your repro, as GM cam timing figures are "out to lunch", and should only be used to show the difference between the 2 factory cams. The "effective" duration you show is probably a more accurate figure for your 3151 repro AND the factory original cams.