Decoding a Camshaft [Archive] - Team Camaro Tech

: Decoding a Camshaft


shelbyz28
Dec 29th, 00, 07:17 AM
What number is cast into the casting area in between the lobes of the cam for a 69 302(DZ)? I'm trying to id the orrg cam, but I've got several to choose from. Also, what are the specs on the cams that came from the factory?
I know the decoding is a little strange, but if anyone has info, I'd sure appreciate it.
Thanks

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Joel
1969 Z28
LeMans Blue-White Stripes
#'s matching, P-O-P

pdq67
Dec 29th, 00, 11:24 AM
The big Duntov "fuelie" cam is:

254/254 @ .050", 485"/485" gross lift, 114 LCA/111 ICA, (It needs .030"/.030" lash)

The factory advertised duration was like 345 or something wild because they rated it at .002" or something weird like that, but I think it's more like a 304 duration if rated at a .015" standard now a days. IMHO. pdq67

JohnZ
Dec 29th, 00, 05:26 PM
Don't know what the casting number is, but the finished camshaft part number is 3849346 for the 30-30 Duntov used in the Z28. Valves must be lashed hot, with the engine running with this cam (ramps are too long to set the valves accurately with the traditional shop manual method - that's why the shop manual specifically states "hot and running" for this cam).

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JohnZ
'69 Z28 Fathom Green

pdq67
Dec 29th, 00, 07:16 PM
Oh, Crane makes a duplicate of the old -346 fuelie cam if you want one that is identical to the original.

You can probably get one cheaper from Wolverine Blue Racer, though. pdq67

Doug Garland
Dec 31st, 00, 08:13 AM
The casting # is usually one # past the part #, or # 3849347. That was the #'s that were on the original one I had. Bought a Chevelle convertible, and got an engine with it for $35. The engine had sat in a chicken house for years, and froze, and busted. I tore it down, and noticed it had solid lifters, so I pulled the cam, and it was a brand new G.M. solid lift 30/30 cam, still covered in assembly lube. The engine hadn't even been turned over. Sold it to a guy in town with the lifters for $125.

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Many Used Parts for Chevelles, and Camaros- Just ask!

tom3
Dec 31st, 00, 05:23 PM
One thing you can do is get a micrometer and check the lift. Just measure the base and the lobe sizes subtract and multiply by 1.5 to get the acutal valve lift. Get pretty close like this. Numbers I've seen for a stock 302 was for a .455 valve lift.

[This message has been edited by tom3 (edited 12-31-2000).]

pdq67
Dec 31st, 00, 06:23 PM
I'm sorry, the -346 cam is .486" lift. pdq67