NO LT1 cam cores available for custom grinds

Just got that info from Lloyd Elliot. None of the grinders have blank cores now and are waiting for them. I had been trying to get them to respond to my inquiry for week with no response, so the shop that did my block machining tried to order and was told no core, which I confirmed with Lloyd. He said he has 27 customers waiting.

Puts me in tough spot because it is unknown when cores will be available or how long it would take for them to catch up once they get them.

Only custom option seems to be a regrind of my original, that Crower can do. They say 4-6 weeks, though, and they haven't responded since I sent my preferred grind specs.

The only off the shelf cam that is readily available that I have found is the Corvette version, which appears to have been used both with 1.5 and later with 1.6 rockers. It is available as a Melling MC1336. It has about the same duration @.050 and centerline that my grind would have had, but is slow ramps. That slowness gives less lift and area under the curve than the custom and also gives more overlap between .006 and .050, so not as desirable to me. Probably the only viable option if I want to get running in the near future.

The MC1336, per the milling cam spec list is 201/208 @.050, 270/276 advertised, 117* centerline, .447/.459 lift which appears to be with 1.5 rockers.

Anybody ever run that cam in a wagon???? Stock 1600 rpm stall speed and with 3.23 gears.

Can they get a cam blank for an LO3/5? The difference is the length of the pin in the front for the timing set to locate on. You can put an LT1 cam in an LO3/5 by shortening the pin, so the reverse should also be true by putting a longer pin in an LO3/5 blank.

Thanks Fred, that core looks to be an 08, and it doesn't appear they are around either, which makes sense as they probably stock cores without the pin so they can do either at order.

I did however find a pretty oddball cam on the 08 core available off the shelf, looks like a turbo or nitrous cam, but listed as low end power high mileage. Stump puller would be more like it, I think. One nice thing is that they have a lot of split to the exhaust instead of doing higher lift there with less duration split. With cast manifolds and full stock exhaust more time pushing is probably better than trying to just let more out of the cylinders. That was what I did on the turbo motors.

08-525-8 and it does have "interesting" specs! Even less overlap than what I had speced with a little less lift.

I have one of those Melling MC1366's sitting around, PM me Booster if you want it.

lamune wrote:

I have one of those Melling MC1366's sitting around, PM me Booster if you want it.

Thanks for the offer, I may take you up on it later.

Right now, I am going to give a try of the oddball gen I cam, even though it will require a pin change and maybe center hole enlarging. Best I can find, I think, that I can actually get within 6 months.

It looks almost like a turbo cam, but they list it as low end torque, high mileage.

Comp 08-525-8. 246/258 adv, 194/206 @ .050, .476/.464 with 1.5 rockers. It has a huge -35* overlap at vs -29* for the stock cam and the one I speced as custom. +20* at .006 vs +25* for the speced and +36* for stock one. Will have very high dynamic compression, I think, and very early torque. Comp has it rated 800 to 5000, but they always seem to stretch both ends compared to the real world, so I would expect more like 1000 to 4500 or so. This is why the question about slotting pushrod holes with 1.6 lifters in another discussion, as if it is too low rpm it would be easier to put 1.6s on it than change to another cam.

Hey booster, a few thoughts from my experience:
1. Stock stall speed on these cars was 1400rpm, not 1600rpm. I did put a factory 1700rpm stall in my Impala and for the cheap price I paid, it gives a nice little boost without being too sloppy down low. You definitely get what you pay for with smaller-diameter torque converters, though; it's a good place to spend money, and gives you the best of both worlds (tight down low, increased STR up high).
2. I think cam overlap is the single biggest determiner of idle quality.  I just was working on a guy's car with a Trick Flow cam, 220/227 at 0.050, zero overlap at 0.050. I just about had it idling at stock RPMs even though it had 30 degrees more duration than stock on each lobe. O2 sensors were not going crazy at idle as they do with high-overlap cams. Owner was disappointed that it didn't lope at idle. There are other ways in the tune to make that happen.

sherlock9c1 wrote:

Hey booster, a few thoughts from my experience:
1. Stock stall speed on these cars was 1400rpm, not 1600rpm. I did put a factory 1700rpm stall in my Impala and for the cheap price I paid, it gives a nice little boost without being too sloppy down low. You definitely get what you pay for with smaller-diameter torque converters, though; it's a good place to spend money, and gives you the best of both worlds (tight down low, increased STR up high).
2. I think cam overlap is the single biggest determiner of idle quality.  I just was working on a guy's car with a Trick Flow cam, 220/227 at 0.050, zero overlap at 0.050. I just about had it idling at stock RPMs even though it had 30 degrees more duration than stock on each lobe. O2 sensors were not going crazy at idle as they do with high-overlap cams. Owner was disappointed that it didn't lope at idle. There are other ways in the tune to make that happen.

I have actually seen both specs for stall, and when I looked into it and contacted some of the suppliers, most had the same explanation which is probably right. The same converters are used for various applications and stall speed is quite dependent on low speed engine torque so the same converter can have various speeds depending on the application. With the pre LT1 engine the converter could easily have stalled at 1400, but with the very high low end torque of the LT1 engines, especially the iron head ones, the stall would likely be higher. Quite a few places I looked I saw the stock Buick converter rated 1400-1600. The 1700 was often show as 1700-1900 or just at 1800.

Agree on overlap, but idle quality isn't everything, and other things like idle speed, timing, and mixture also come into play besides. That 220/227 would have been on 111 lobe separation to get zero at .050. All the LT1 cams that were stock, including the aluminum head ones, were in the -29* at .050 for overlap so a huge difference. The custom one I wanted to buy would have also had -29*. The oddball one that will be here tomorrow, I hope, for the gen 1, will be at -32*. With a similar cam, but not even to 29* that I put in the last small block Chrysler turbo engine I built, I had it idling at a bit under 400 rpm without issue if I wanted it there. I ran it higher to help the cooling. That engine had extremely good low rpm, off boost, torque, even the 2.76 gears and a manual transmission. That 220/227 on 111 would probably have rated rpm range of 1800 too 5500 rpm or so, but the rpm ratings are always stretched a bit, I think, so would not be very effective without a relatively high stall converter. The stock cams for the iron heads would probably rate in the 1000-4500 range and the one coming tomorrow is at like 800-4500 IIRC.

It all depends on what you are looking for and how you like it to drive. I have found I really liked the way the stock engine torque curve was setup, so just tweaked the details to try to do similar but better and higher output. Will certainly be more responsive and accelerate better with the 3.23 vs 2.56 gears, too.

I never was able to get any answer about if the Comp will have the big nose hole or not, with sources obviously guessing both ways. I should find out tomorrow when it gets here. I do have fixturing designed and ready to finish for the doing it in the Bridgeport so I can get the good concentricity and surface finish needed. I will be boring it with a 1/2" end mill and then using a ball hone to improve the finish, if I have to do it.

Pretty happy camper here today. The off the shelf Gen 1 Comp cam from Jegs showed up today, finally after Fedex sat on it for a while.

The good news is that the Opti nose end has the large hole for the Opti drive and it is the right depth. All I will have to do is change the pin!

This really opens up the range of off the shelf cams that could be found for the LT1 engines, as I assume they are all this way for Gen 1 roller cams.

The manufacturing process guy in me (that is what I did for decades) didn't see why it wouldn't be this way, as it would save a bunch in inventory and costs for the blanks, but nobody could tell me for certain.

Block got done yesterday from the deck height tweak and I washed it as soon as I got home, so ready to start bottom end final assembly and bearing clearance tweaking as soon as I change the pin on the cam tomorrow.