327/365 cam

[65stinger]

Hey folks, I've sort of touched on this subject before, but I've just finished the frame and suspension and starting on the engine. As I've stated before, I'm converting it back to original with the solid lifters and 30-30 cam. My question is, where do you guys suggest I purchase those two items to guarantee I'm getting original equipment. If you have suggestions, could you provide the part no. as well? Again, thanks in advance.....

 

[Sams '66]

Hey folks, I've sort of touched on this subject before, but I've just finished the frame and suspension and starting on the engine. As I've stated before, I'm converting it back to original with the solid lifters and 30-30 cam. My question is, where do you guys suggest I purchase those two items to guarantee I'm getting original equipment. If you have suggestions, could you provide the part no. as well? Again, thanks in advance.....

Jegs might have 'em.....

 

[6T5RUSH]

65stinger,

I've had no problem finding the factory replacement cam (in my case I went for the LT1 version offered 70-72 ((GM#3972178)) made by Federal Mogul (#CS1145R). I bought this through CARQUEST. I had trouble finding the original GM lifters (GM#5231585). Ended up at Tracy Performance...paid a pretty penny, but they came in the GM boxes. Federal Mogul part # for this is AT840R but its discontinued, replaced by their part #AT992.

I would call Federal Mogul's Help Line (sorry, don't have it). At least they can provide you with the GM# for the 30/30 and cross refence it to FM's #.

Good luck!

 

[JohnZ]

Having many years of experience with the "30-30" cam in both Corvettes and Z/28 Camaros, I wouldn't recommend using it for a rebuild due to its marginal low-end torque; I'd do as Jim mentioned and use the LT-1 cam, which was the ultimate development (six more years of work beyond the "30-30") of the Chevy factory solid-lifter street cams; it has wider torque bandwidth, 20% more low-end torque than the "30-30", and gives up less than 1% power at 6500 rpm vs. the "30-30". Don't sweat the edge-orifice vs. piddle-valve lifters for a street engine - any Chevy solid lifter will work just fine.

 

[Ken Anderson]

I would second John's opinion-everything he says is correct. If you install the old cam you will very disappointed.

 

[65stinger]

Excellent folks, Thats exactly the kind of answers I've been wanting to hear. I 'll go that route with the LT-1 cam. I'm thouroghly impressed with this group and the great responses I've been getting. I hope ya'll are patient with me. This is my first corvette restore (frame off) and I'm sure I'll have many more questions.

Also John Z, I've got a copy of that valve setting procedure you provided and plan on using it......I take it, it still works the same with this cam as well?

 

[Tuna]

After driving a 30-30 cammed car for a few years, it would not be my first choice for a car I wanted to drive very often. Low end torque is awful. Below 3k it was pretty flat. However, 3k to 7.5k was a kick.

If originality is the more important than driveability, then the 30-30 is the way to go.

 

['63split]

I have a question to tack on to this thread.

I own a '63 with a 340 hp 11.25 - 1 compression engine and I'm having a tough time finding the right fuel mix so it doesn't knock. What is preferred, retarding timing, lead additive or aviation gas? Just wanted to know what you all found that works to reducing knocks.

Thanks,
Mike

 

[66427-450]

Having many years of experience with the "30-30" cam in both Corvettes and Z/28 Camaros, ....... I'd do as Jim mentioned and use the LT-1 cam, ......... and gives up less than 1% power at 6500 rpm vs. the "30-30".

Interesting...... I wonder what the difference would be (LT-1 & 30-30) in a 327 with open headers, say, in the ~4500-7500 RPM range? Seems like that's what the cam was designed for; hi performance/racing use with a free flowing exhaust system.

When we raced the little '68 302, we performed better with "more" cam.... more than the std. FI/Z-28 30-30 cam, but granted, that was with 4.88's and open big tube headers.

 

[MBDiagMan]

The 30 30 was a good cam for it's time, but technology has advanced drastically since then.

In an SBC with ANY solid lifter cam, plan on spending your Saturdays adjusting lifters. There are MANY good hydraulic grinds that are far superior, but, of course, they won't sound the same.

If you do stay with solids, a timing tape properly applied to the balancer will make lifter adjustment go much faster. I don't know if it's still available, but in the early 70's I used a timing tape that I think was a Mr. Gasket product. It had codes on the tape. You simply started at TDC on the compression stroke and kept turning to the marks and adjusting the indicated valve. After two turns you were done. This was where the wing bolts on the valve covers and buying valve cover gaskets by the box came in handy.

Properly adjusted though, there was no RPM limit.

Good luck,

 

[Hib Halverson]

[QUOTE='63split]I have a question to tack on to this thread.

I own a '63 with a 340 hp 11.25 - 1 compression engine and I'm having a tough time finding the right fuel mix so it doesn't knock. What is preferred, retarding timing, lead additive or aviation gas? Just wanted to know what you all found that works to reducing knocks.

Thanks,
Mike[/QUOTE]

First, don't use octane boosters. None of them on the market are capible of raising the octane of 91-93 oct. pump gas to the level you need.

Second, avoid retarding the timing. To keep the engine out of detonation, you'll have to retard the spark so much the engine will suffer poor drivability, poor fuel economy and will run warm.

If you don't care about ultimate performance, you can mix AVGAS Low Lead 100 with pump gas. I'd start at about 1:4 AVGAS to pump gas and see how that works. If you have no knock, drop the mix to 1:5. This may require a calibration change to the carb.

If you care about ultimate performance of the gasoline, you're better to mix 100-oct. unleaded racing gasoline with pump gas in the mixes listed above.

For more information on gasoline for street high-performance and racing Corvettes, see:
http://www.idavette.net/hib/fuel/index.htm

 

[bossvette]

Just a question isn't running unleaded gas in an older car hard on the soft valve seats, I was under the impression that when they took the lead out of the gas, manufacturers went to hard valve seats to compensate or is that an "old wives tale"?

Hib will you be attending Cruise-Fest 2004 ?

PS remember high test at 31.9

 

[Copdogcorvettes]

Chech with GM Performance Parts. They have what you are looking for and it is all GM parts. I don't have time this morning to look up the part numbers for you in the caralog I have from them. Got to go pick up the other half at the airport; it's a 2 hours drive just to get there. The phone number I have for them is:

1 800 577-6888

Or let me know where you live and I'll look up the nearest Authorized center to you. There is a list in the back of the catalog I have.

Hope this helps in some way,

Gary

 

['63split]

Thanks Hib,

I have a friend who has access to AVGAS that he said is rated at about 130 octane. He pumps it into 10 gallon cans. I'm not hard on the car since both the car and I are showing our age. I'm mainly a cruiser now, so a lighter mixture of 4:1 or 5:1 should be sufficient.

Mike

 

[JohnZ]

Excellent folks, Thats exactly the kind of answers I've been wanting to hear. I 'll go that route with the LT-1 cam. I'm thouroghly impressed with this group and the great responses I've been getting. I hope ya'll are patient with me. This is my first corvette restore (frame off) and I'm sure I'll have many more questions.

Also John Z, I've got a copy of that valve setting procedure you provided and plan on using it......I take it, it still works the same with this cam as well?

If you check the second page of the procedure, it covers the "cold" adjustment for an LT-1; only the exhausts need to be set with the indexing procedure, as they are still on the clearance ramps at TDC - the intakes are off the ramps at TDC (unlike the "30-30", where both intakes and exhausts are still on the ramps at TDC - the only Chevy factory cam ever designed that way). With stock stamped rockers, set the intakes at .021" and the exhausts at .026" (cold).

 

[JohnZ]

Interesting...... I wonder what the difference would be (LT-1 & 30-30) in a 327 with open headers, say, in the ~4500-7500 RPM range? Seems like that's what the cam was designed for; hi performance/racing use with a free flowing exhaust system.

When we raced the little '68 302, we performed better with "more" cam.... more than the std. FI/Z-28 30-30 cam, but granted, that was with 4.88's and open big tube headers.

The "30-30" and LT-1 cams were designed for optimum power with production ram's horn exhaust manifolds, and the exhausts open a bit earlier as a result, to help with the exhaust port flow restriction and the stock manifolds. The 1st-design "-140" service cam for the 302, on the other hand, was designed for use with headers and open exhaust (as were the L-88 and ZL-1 cams) with a later closing exhaust valve, and that's what the '69 Trans-Am Camaros used (it was legal for '69 SCCA, as it was available over-the-counter). The "second design" 302 service cam was even nastier, but it compromised torque to the point where nobody used it - the ultimate example of "too much cam", even for a race car.

 

[JohnZ]

Just a question isn't running unleaded gas in an older car hard on the soft valve seats, I was under the impression that when they took the lead out of the gas, manufacturers went to hard valve seats to compensate or is that an "old wives tale"?

Hib will you be attending Cruise-Fest 2004 ?

PS remember high test at 31.9

The issue here is "duty cycle" - how hard the engine is run, under what load, and for how long on a continuous basis. Valve seat recession on leaded-fuel engines running on unleaded fuel was an issue on some engines used for continuous high-output/high-load conditions, like heavy trucks, stationary agricultural pumps and generators, but it's essentially a myth on cars that see the kind of use our classics do, unless you decide to pull a loaded trailer at 100mph all day long. The marketers of all the "miracle" lead additives (none of which have any lead in them) would have you believe that your engine will self-destruct unless you use their product - it ain't gonna happen. Just drive it and don't worry about it.

 

[ctjackster]

so much smack about the 30-30 cam that lives in my 65 L76!

what, you no like acting like John Force at the winter nationals, revving that engine up high before the tree goes green, in order to launch that L76 from a standing start?

isn't that part of the SHP "experience"? :L

 

[65stinger]

OK John, so for example, to start with, I set the #1 TDC and set the #8 exhaust at .026 and the #2 intake at .020. and continue at 90 deg turns.....? Or start at 90 deg before #1 TDC? Please be patient with me, for this is my first stab at setting these cold.

 

[65stinger]

Sorry, nevermind....had to read the procedure one more time......I can set all the intakes at TDC, but I need to set the exhaust at 90 BTDC.....Thanks again.