Engine bearing & piston-wall Clearances?

D-Con

...Rather have a Buick?
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Mar 13, 2006
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There's alot of superstitious talk about the best oil for the Terminators, and some say the 5W-20 oil is spec'd because of the engine's "tight clearances" compared to "older" engines.

Well here we have the mighty GT-500 (which is why I posted here) with a bigger engine and other parts, but my guess is it has no difference in clearances from the Terminator but specifies 5W-50 oil. I suspect the 5W-50 helps prevent sticking a piston during the 150 mph pulls.

I've discounted all of the other oil myths, and personal preferences except this one. Can anyone tell me if there are any different internal clearances with the GT-500 engine, or confirm that there is no difference?

I'm an answer and an oil change away from using 5W-50 in my Terminator. Maybe the 5W-50 will keep it from terminating prematurely... TIA!
 

Fourcam330

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The answer to the 5w-50 riddle is that GT/R/GT500 lifters/adjusters are smaller than other Modular heads. Without the heavier weight oil they tend to collapse quicker which translates into reduced cam lift/duration and consequently less power.
 

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