Here's an example of a "phenomenon" that I've seen occur all-too-often. I'm sure that judges encounter it quite a bit, too. On the "Gold Field" at Bloomington I spotted a pretty nice looking 1970 Corvette with LS-5. When I looked in the engine compartment I noted this "idler pulley" (and also, by the way, an unused groove on the waterpump pulley). There seemed to be 2 people there selling the car, an older gentleman and a younger one. It may have been a father and son, but I believe it was the son that actually owned and was selling the car. Anyway, since the car was otherwise such a nice car (apparently), I mentioned to the older gentleman that the "idler pulley" set-up on the car was not correct and looked like something someone had concocted to eliminate the captured belt (which is, of course, so difficult to replace). He was very nice and responded that, indeed, it did look a little "homemade". At that point the younger fellow came over, acted like he was tired of "neophytes" telling him how the car should be, and said that the idler pulley set-up was completely correct and original. He was just positive of it because "he had seen exactly the same set-up on a lot of other 1970 Corvette big blocks". At that point, the older gentleman said "well, I guess that's how it is". I walked away.
It's always difficult to say "never" to anything. However, I really feel that I can say that NO 1970 Corvette, or any other Corvette, ever left the factory with an idler set-up like this one. Among other things, you will note that the "idler" apparently has no bearing; it's just a pulley, attached to a bolt running without bearing in a steel bracket. GM never used a configuration like this on any V-belt drive system I'm aware of (although they did on some much later serpentine belt systems).
By the way, some 1970 Corvettes with LS-5 did use an idler pulley assembly. However, this was limited to cars with C-60, which the car in question did not have. Plus, the idler pulley was mounted on the LEFT LOWER side of the engine and was a BEARING-type idler, not at all a contraption as is seen here.
Also, note the location of the temp sender in the photo; I'll bet the owner is "just positive" that's as-original, too.
So guys, if you see one of these things out there and someone tells you it's original, it's NOT.
It's always difficult to say "never" to anything. However, I really feel that I can say that NO 1970 Corvette, or any other Corvette, ever left the factory with an idler set-up like this one. Among other things, you will note that the "idler" apparently has no bearing; it's just a pulley, attached to a bolt running without bearing in a steel bracket. GM never used a configuration like this on any V-belt drive system I'm aware of (although they did on some much later serpentine belt systems).
By the way, some 1970 Corvettes with LS-5 did use an idler pulley assembly. However, this was limited to cars with C-60, which the car in question did not have. Plus, the idler pulley was mounted on the LEFT LOWER side of the engine and was a BEARING-type idler, not at all a contraption as is seen here.
Also, note the location of the temp sender in the photo; I'll bet the owner is "just positive" that's as-original, too.
So guys, if you see one of these things out there and someone tells you it's original, it's NOT.
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