Chevy Astro 4.3 and A 4.3 H.O.

Old 07-28-07, 11:01 AM
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Chevy Astro 4.3 and A 4.3 H.O.

Can someone tell the differences in a 1990 chevy astro standard 4.3 and and the high output 4.3. what are the different parts they used. the reason im asking is i need a intake manifold and theres one at the junkyard but it 4.3 h.o.

thank you
Old 07-28-07, 12:30 PM
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There's a Throttle body injected "Z" engine and a Vortec "W" engine........Check your 8th digit on your VIN and compare with the one you're snatching the intake out of
Old 07-28-07, 12:41 PM
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Another BIG difference are the heads! The water ports on the Vortec do not match the intake of the '90 model.
When I change mine over I had to have the entire top end reworked (valve job, shaved heads etc.). If you use the Vortec intake and heads, you have to change over the wiring harness and computer system. If you continue to use you old heads and intake, it's best to have them reworked.

One significant problem with mixing the parts (intake of old swapped with vortec intake) is that the intake of the old motor does not close a gap at the rear of the intake. The Vortec intake is made to fit tightly. The gap can be sealed but is very difficult and if it's not sealed properly, you'll leak oil badly.

good luck!

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