1969 L88 camshaft

[Bob J.]

Re: 1969 L88 camshaft

I think the 3879605 was used for 67 and early 68. The 3925535 was then used for the rest of 68 and 69.

Michael, I bought a few NOS L88 cams from Smokey Yunick and the 3879605 cams I got only have a 4 digit stamped number on the end of the rear journal.Bob

[Dick W.]

Re: 1969 L88 camshaft

Michael, I bought a few NOS L88 cams from Smokey Yunick and the 3879605 cams I got only have a 4 digit stamped number on the end of the rear journal.Bob

Junky, I can tell you for a fact that the parts you bought from the Smoke, were not necessarily what you thought you bought. Case in point, we ran a '68 Camaro in the NASCAR Grand American circuit. Piggins told us to get all our engine parts from "the Best Damn Garage in Town". Valve spring on seat pressure was probably 30-40% over what the specs called for. The engine would make power way above where it was supposed to peak. He was the Skunk Works for Chevrolet, always testing new parts.

[Bob J.]

Re: 1969 L88 camshaft

Junky, I can tell you for a fact that the parts you bought from the Smoke, were not necessarily what you thought you bought. Case in point, we ran a '68 Camaro in the NASCAR Grand American circuit. Piggins told us to get all our engine parts from "the Best Damn Garage in Town". Valve spring on seat pressure was probably 30-40% over what the specs called for. The engine would make power way above where it was supposed to peak. He was the Skunk Works for Chevrolet, always testing new parts.

DW , I can't argue that many of the parts Smokey had were tweaked.
I can tell you on the experimental 396/427 cams I bought most were stamped CAMCRAFT DETROIT. RJ

[Michael H.]

Re: 1969 L88 camshaft

Michael, I bought a few NOS L88 cams from Smokey Yunick and the 3879605 cams I got only have a 4 digit stamped number on the end of the rear journal.Bob

Was the 4 digit number close to the 9605 or the 4367?

[Dick W.]

Re: 1969 L88 camshaft

Junky, I cannot remember what the difference was, but we ordered a set of lifters from Smokey and he only shipped 15. We thought that we could go to Chevrolet and get the last one, wrong. They were very different although they came in the GM boxes.

[J W.]

Re: 1969 L88 camshaft

Wow! Thank you everyone for looking through their archives and parts to help clarify some of these issues. But, I still don't feel any closer to finding a cam for an engine rebuild on my legitimate 1969 L88, unless I find a 3925535 NOS cam for sale which is looking unlikely. The specs for that cam are Lift .562 intake/.584 exhaust; advertised duration 354 intake/360 exhaust; duration at .050" 264 intake/269 exhaust; lobe separation angle 112 degrees. Can anyone give me any advice or recommend a cam from one of the current manufacturers? I want it to be authentic and sound like an L88 but wouldn't mind more low end torque. I also want to stay below .600 lift to avoid valvetrain durability issues. I talked to the tech guys at Comp Cams and Summit and they couldn't give me a firm recommendation. My engine builder asked me to talk to some more experts (you guys) before we make a choice. My interest is more in authenticity to maintain the value of the car than driveability.

[Richard F.]

Re: 1969 L88 camshaft

Have you tried ordering PN# 12364058 from gmpartsdirect?

[Joe L.]

Re: 1969 L88 camshaft

Have you tried ordering PN# 12364058 from gmpartsdirect?

Richard-----


Unfortunately, that part has been GM-discontinued. These kits were manufactured for GM by Crane. I suppose that with the demise of Crane, so "goeth" these kits. There might be a few in dealer inventory somewhere, though.

[Clem Z.]

Re: 1969 L88 camshaft

goggle the part # and see what shows up.

[Bob J.]

Re: 1969 L88 camshaft

Was the 4 digit number close to the 9605 or the 4367?

I think the number was 9606.RJ

[Duke W.]

Re: 1969 L88 camshaft

Can anyone give me any advice or recommend a cam from one of the current manufacturers? I want it to be authentic and sound like an L88 but wouldn't mind more low end torque.

These goals are fundamentally mutually exclusive, but my recommendation is to run the 425/435 HP cam - still mechanical lifters and very streetable, and you can always diddle with the idle mixture and timing to give it a more knarly idle. This cam will yield much better low end torque and about the same top end power with manifolds and mufflers. As is the case with all OE engines of this vintage, the secret to "more power" is head massaging.

The Federal Mogul Speed Pro number for this cam is CS-165R, and you can order it from NAPA. It should have a groove in the rear journal.

BTW, an acquaintence of mine with with a 496 stroker/massaged head (with 1.88" exhaust valves, which I recommend with a single pattern cam) L-71 was not happy with the performance, especially the bottom end and idle quality, and it turned out he had a Crane cam with about the same duration as the OE cam, but the LSA was 110 rather than 114 deg. He did a chassis dyno test, then, on my recommendation, swapped in a new OE spec cam with six degrees retard and retested. The engine made both more low end torque and MORE TOP END POWER!!! It's got so much low end that first and second gears are nearly unusable at WOT, but he likes having more torque than the chassis/tires can handle.

It was all about reducing overlap to something more compatible with manifolds and mufflers, and the six degrees retard was to get a little more top end at the expense of the bottom end, which I knew would be way more than the chassis and tires could handle with the OE indexing, and it still is with six degrees retard.

With the 110 degree LSA Crane cam on a chassis dyno it made (SAE corrected) 433 lb-ft @ 3650 and 350 RWHP @ 5500. After installing the OE spec cam with six degrees retard it made 433 lb-ft @ 3900 and 362 RWHP @ 5800. Unfortunately as is the case with so many dyno tests, the pulls were started in the 2500-3000 RPM range so the beginning of the 80 percent torque bandwidth was not determined, but the owner's SOTP impression is that the OE cam produces significantly more low end torque below 2500.

With a 4.25" stroke 5800 equates to a mean piston speed of about 4100 FPM, which is equivalent to 6550 revs on a 427.

And the above is through the very restrictive OE sidepipes. His next project is to install less restrictive aftermarket pipes under the OE covers. This should get peak torque to around 450 and peak RWHP close to 400!

In normal driving, it's very docile. He modified the center carb vacuum advance passage to get full time vacuum advance, so OE appearance of the vacuum advance line remains unchanged, which along with the long stroke and OE cam yield an almost "too tame" idle. And in his normal 90-100 degree summer temperatures, it has no tendency to overheat!

Duke

[J W.]

Re: 1969 L88 camshaft

Duke

Thank you for your response and for sharing your knowledge! I am going to discuss this with my engine builder.

Michael

[Richard M.]

Re: 1969 L88 camshaft

Mike, call Bullett Cams in MS. they will build you a cam to your factory specs. they make cams for the NHRA Stock and Super Stock racers.