Cam Shafted


I am told that ’68 340s used a dif- ferent cam than the later engines. What can you tell me about it

First of all, your statement is about 25% right. How do I arrive at that number? Well, only the manual trans ’68s used a unique cam (deduct 50%), then it was used only during the first half (or so) of the year…so one half of ½ = ¼ (25%). OK, now that I have totally ripped you a new one, I’ll get down to facts. Except- ing those early ’68 340 MT cars, all 340s used a cam with these specs (all are measured at 0.006˝ lift): INT 268° Duration, 0.429˝ lift EXH 276° Duration, 0.444˝ lift. The early 1968 MT cars were significantly more radical: INT 276° Duration, 0.444˝ lift EXH 284° Duration, 0.453˝ lift. That, however, is not the end of the story. In some actual printed advertisements for the ’68 Cars, the MT cam was spec’d at 282/294°. Until someone produces either a NOS or lightly- worn OEM camshaft for checking (P/N 2899205), this will remain unproven conjecture. I will, however, tell you that those cars ran like stink, dead stock I am willing to bet that the SAE gross HP number was 310-320.Which brings me to another unanswered question: Which made the most HP dead stock? That ’68, the ‘70 340-6 (which used the common camshaft), or the ’71 (great intake—800 CFM Carter, slightly more restrictive air cleaner, and lousier exhaust). With unmo- lested parts (esp. cylinder heads and stock-bore blocks) rapidly disappearing, we may never know, but a ’68 340 MT engine, with a ’71 intake or 6-Bbl, sure would be a ripper. One other comment: That ’68 cam would suck in a later low-C.R. engine. FYI: after ’71, the 340s were castrated— much lower C.R. The ’74–’76 360 was actually a much better engine.

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