Help with camshaft selection for 350 SB

[Michael L.]

Guys,

I'm currently rebuilding my 69 350/350 SB and wanted to see if there were any opinions out there about camshaft selection. I have long thought that I wouldn't do anything but replace the stock camshaft for originality, but I have to admit there is a certain attraction to getting an hydraulic roller for ease of break in/maintenance and not having to worry nearly as much about rounding out a cam lobe. Does anyone have experience with hydraulic rollers in a similar build? Any recs on a specific grind? Thanks.

Mike

[Joe L.]

Re: Help with camshaft selection for 350 SB

Guys,

I'm currently rebuilding my 69 350/350 SB and wanted to see if there were any opinions out there about camshaft selection. I have long thought that I wouldn't do anything but replace the stock camshaft for originality, but I have to admit there is a certain attraction to getting an hydraulic roller for ease of break in/maintenance and not having to worry nearly as much about rounding out a cam lobe. Does anyone have experience with hydraulic rollers in a similar build? Any recs on a specific grind? Thanks.

Mike

Mike-------


You can still get the original camshaft for your application from GM. GM #3896962 and one of the very few original 60's era camshafts available from GM. One of the reasons that it's still available is that GM actually uses this camshaft in some crate SERVICE engines.

Would I use the above in an engine I built today? Not a chance. Hydraulic roller is the only way to go for a lot of reasons. I can't recommend a grind to you at the moment but I'm sure there are many out there that will deliver characteristics similar to the 3896962. I'd consult one of the cam manufacturers technical departments.

[Mark E.]

Re: Help with camshaft selection for 350 SB

I vaguely remember a fairly recent thread with entertaining point-counterpoint banter about roller vs. original cams between Duke and Joe L.
You might search for it.

[Gene M.]

Re: Help with camshaft selection for 350 SB

A stock 60's SB is not going to gain anything by using a roller cam. The 461, 462 heads are not going to give the flow benefit. A small aftermarket flat tappet will be just as well performance wise. In fact an L79 is a good cam choice. Your attention would be better spent blending out and pocket porting the heads. Unless you are going to use aftermarket heads with plenty of up grades you are looking in the wrong area. But your money to waste it as you will.

[Joe L.]

Re: Help with camshaft selection for 350 SB

A stock 60's SB is not going to gain anything by using a roller cam. The 461, 462 heads are not going to give the flow benefit. A small aftermarket flat tappet will be just as well performance wise. In fact an L79 is a good cam choice. Your attention would be better spent blending out and pocket porting the heads. Unless you are going to use aftermarket heads with plenty of up grades you are looking in the wrong area. But your money to waste it as you will.

Gene------


It didn't sound to me like Michael was interested in improving performance since, if he decides to use a roller cam, he apparently wants something equivalent to the original cam. Of course, performance benefits could be achieved if he were to select a higher performance camshaft profile. Roller cams allow profiles which cannot be utilized with flat tappet cams. That's one of the benefits of a roller cam.

In any event, among the benefits that will result with the use of a roller cam is relative freedom from flattened cam lobes. Wipe out just one cam and the resultant cost will be greater than the cost differential between a flat tappet cam/lifters and an hydraulic roller cam/lifters----not to mention the work and aggravation. Another benefit is greatly reduced internal engine friction, always a benefit.

Flat tappet camshafts have not been used in any PRODUCTION engine I know of in 25 years. Roller cams have proven to be highly reliable and durable. In my opinion, flat tappet camshafts are obsolete.

[Jim D.]

Re: Help with camshaft selection for 350 SB

Gene------
Flat tappet camshafts have not been used in any PRODUCTION engine I know of in 25 years. Roller cams have proven to be highly reliable and durable. In my opinion, flat tappet camshafts are obsolete.

Chevy trucks used flat tappet cams until 1996 and there are 100's of millions of them out there running modern oil with no problems. I've built MANY engines with FT cams and NEVER had one go flat. I can't get over spending $400+ just for the lifters to convert to rollers that have no obvious advantage.

[Joe L.]

Re: Help with camshaft selection for 350 SB

Chevy trucks used flat tappet cams until 1996 and there are 100's of millions of them out there running modern oil with no problems. I've built MANY engines with FT cams and NEVER had one go flat. I can't get over spending $400+ just for the lifters to convert to rollers that have no obvious advantage.

Jim------


Well, OK, 20 years.

There's no significant failure problem with a flat tappet cam once it's broken in. It's during the break-in process that most flat tappet cam failures occur. In the last several years, I've heard of a lot of these sort of problems.

Regardless, I've been a fan of hydraulic roller cams for a long time. In fact, I purchased one of the first retrofit hydraulic roller cam kits on the market. It was released by Speed-Pro more than 20 years ago.

[Duke W.]

Re: Help with camshaft selection for 350 SB

It's tough to beat the OE cam, which is also available from Federal Mogul, CS-1095R, and is likely much cheaper than the GM sourced part, which is likely also the same piece manufactured by F-M. It uses the same valve springs as a contemporaneous 283 2 bbl., (FM VS-677) so it's easy on the valve train, and if you use CJ-4 engine oil the chances of wiping a lobe are extremely low.

If you want "more power" massage the heads. I think this is a much wiser use of funds than converting to a roller cam, most of which have too much overlap and will roughen the idle and lose low end torque.

With proper valve spring height setup it should rev to at least 6500, and with massaged heads it will make useable power to that point.

Duke

[Gene M.]

Re: Help with camshaft selection for 350 SB

Gene------


It didn't sound to me like Michael was interested in improving performance since, if he decides to use a roller cam, he apparently wants something equivalent to the original cam. Of course, performance benefits could be achieved if he were to select a higher performance camshaft profile. Roller cams allow profiles which cannot be utilized with flat tappet cams. That's one of the benefits of a roller cam.

In any event, among the benefits that will result with the use of a roller cam is relative freedom from flattened cam lobes. Wipe out just one cam and the resultant cost will be greater than the cost differential between a flat tappet cam/lifters and an hydraulic roller cam/lifters----not to mention the work and aggravation. Another benefit is greatly reduced internal engine friction, always a benefit.

Flat tappet camshafts have not been used in any PRODUCTION engine I know of in 25 years. Roller cams have proven to be highly reliable and durable. In my opinion, flat tappet camshafts are obsolete.

Joe,
If you understood my post I suggested a GM cam grind. You stated "Roller cams allow profiles which cannot be utilized with flat tappet cams. That's one of the benefits of a roller cam." It seems your support of a roller is without merit or sound reasoning.

As Duke points out:
It's tough to beat the OE cam, which is also available from Federal Mogul, CS-1095R, and is likely much cheaper than the GM sourced part, which is likely also the same piece manufactured by F-M. It uses the same valve springs as a contemporaneous 283 2 bbl., (FM VS-677) so it's easy on the valve train, and if you use CJ-4 engine oil the chances of wiping a lobe are extremely low.

If you want "more power" massage the heads. I think this is a much wiser use of funds than converting to a roller cam, most of which have too much overlap and will roughen the idle and lose low end torque.

With proper valve spring height setup it should rev to at least 6500, and with massaged heads it will make useable power to that point.

[Joe L.]

Re: Help with camshaft selection for 350 SB

Joe,
If you understood my post I suggested a GM cam grind. You stated "Roller cams allow profiles which cannot be utilized with flat tappet cams. That's one of the benefits of a roller cam." It seems your support of a roller is without merit or sound reasoning.

As Duke points out:
It's tough to beat the OE cam, which is also available from Federal Mogul, CS-1095R, and is likely much cheaper than the GM sourced part, which is likely also the same piece manufactured by F-M. It uses the same valve springs as a contemporaneous 283 2 bbl., (FM VS-677) so it's easy on the valve train, and if you use CJ-4 engine oil the chances of wiping a lobe are extremely low.

If you want "more power" massage the heads. I think this is a much wiser use of funds than converting to a roller cam, most of which have too much overlap and will roughen the idle and lose low end torque.

With proper valve spring height setup it should rev to at least 6500, and with massaged heads it will make useable power to that point.

Gene------

A roller cam enables the use of lobe profiles which cannot be used with a flat tappet lobe profile. That is one of the benefits of the use of a roller cam. Period. A flat tappet lifter cannot follow any lobe profile which could be imagined (and which might be beneficial). A roller lifter can follow a much wider range of profiles. Period. This is exactly the reason that mechanical roller camshafts and lifters have been used in racing applications for years. Hydraulic roller lifters bring the same sort of benefits for a street cam that being the ability to use lobe profiles that would not be possible with a flat tappet cam and lifters.

[Michael L.]

Re: Help with camshaft selection for 350 SB

Guys,

I have heard of way too many cam lobes wiping out in the break in for me to be confident putting one in my engine. That is the sole reason for my inquiry to begin with. My local engine shop has stopped assembling engines anymore (except for select customers) after 30 years of building great engines due to all the cam lobes wiping out. They can't be bothered with the hassle. It's not at all a performance issue...if it costs $400 to virtually eliminate the risk of wiping out a cam lobe, then I'm in. I'm not really interested in improving the performance. Its a stock rebuild in every other respect.

Joe, if I go with a hydraulic roller can I use the stock rocker arms? I don't want to have to get tall valve covers.

Mike

Mike

[Joe L.]

Re: Help with camshaft selection for 350 SB

Guys,

I have heard of way too many cam lobes wiping out in the break in for me to be confident putting one in my engine. That is the sole reason for my inquiry to begin with. My local engine shop has stopped assembling engines anymore (except for select customers) after 30 years of building great engines due to all the cam lobes wiping out. They can't be bothered with the hassle. It's not at all a performance issue...if it costs $400 to virtually eliminate the risk of wiping out a cam lobe, then I'm in. I'm not really interested in improving the performance. Its a stock rebuild in every other respect.

Joe, if I go with a hydraulic roller can I use the stock rocker arms? I don't want to have to get tall valve covers.

Mike

Mike

Mike------


Yes, stock, stamped steel rocker arms are fine with a roller cam. However, you do have to use different length pushrods (because roller lifters are taller). Your best bet is to obtain a kit which includes the cam, lifters, pushrods, and cam button.

[Jim D.]

Re: Help with camshaft selection for 350 SB

Guys,

I have heard of way too many cam lobes wiping out in the break in for me to be confident putting one in my engine. That is the sole reason for my inquiry to begin with. My local engine shop has stopped assembling engines anymore (except for select customers) after 30 years of building great engines due to all the cam lobes wiping out. They can't be bothered with the hassle. It's not at all a performance issue...if it costs $400 to virtually eliminate the risk of wiping out a cam lobe, then I'm in. I'm not really interested in improving the performance. Its a stock rebuild in every other respect.

Joe, if I go with a hydraulic roller can I use the stock rocker arms? I don't want to have to get tall valve covers.

Mike

Mike

Sounds like you have your mind made up. Be aware that depending on brand, just the cam and lifters will run $600 - $1000. You'll still need push rods etc. Personally, I think it's a waste of money but since it's not mine, spend away.

[Patrick H.]

Re: Help with camshaft selection for 350 SB

I have heard of way too many cam lobes wiping out in the break in for me to be confident putting one in my engine. That is the sole reason for my inquiry to begin with. My local engine shop has stopped assembling engines anymore (except for select customers) after 30 years of building great engines due to all the cam lobes wiping out. They can't be bothered with the hassle. It's not at all a performance issue...if it costs $400 to virtually eliminate the risk of wiping out a cam lobe, then I'm in. I'm not really interested in improving the performance. Its a stock rebuild in every other respect.

Every case I can recall hearing about was a solid lifter cam, not a hydraulic like your 350/350 cam. With the right oil and break-in additives the odds of this even with a solid lifter cam have gone down significantly. I would wonder if your builder had issues with solids, and made the decision to change his practice based on those.

I would have no qualms about installing a hydraulic cam, but that's me.

[Joe L.]

Re: Help with camshaft selection for 350 SB

Sounds like you have your mind made up. Be aware that depending on brand, just the cam and lifters will run $600 - $1000. You'll still need push rods etc. Personally, I think it's a waste of money but since it's not mine, spend away.

Jim------


Yup, that's just about what a kit will cost. However, the kits usually include cam, lifters, pushrods, and cam button. The retrofit kits, required for pre-1987 small blocks, cost more than hydraulic roller cam and lifters for later small blocks originally equipped with hydraulic rollers.

Good things often cost a lot of money. I've got lots of NOS GM camshafts and NOS GM lifters, big block and small block [none for sale], but you'd never catch me using any on an engine of mine. Never.