305 carb to 350 carb (tbi
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Joined: Aug 2008
Posts: 44
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From: ATLANTA
Car: 86 Z-28
Engine: 350 VORTEC
Transmission: T-5
Axle/Gears: STOCK
305 carb to 350 carb (tbi
Hello forum. I have a 86 Z28 305carb 5speed. I have came across a 350 tbi engine out of a 92 1500. It's been a long time since I've work on a car. So im asking is there anything i might need for this install to go smoothly.
Do i need to swap oil pan.
Can the 305 intake swap over to 350.
Do i need to swap oil pan.
Can the 305 intake swap over to 350.
Joined: Sep 2005
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Re: 305 carb to 350 carb (tbi
Do i need to swap oil pan.
Can the 305 intake swap over to 350.
Joined: Mar 2000
Posts: 43,187
Likes: 46
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Re: 305 carb to 350 carb (tbi
Never heard of a truck LO5 pan not fitting in a 3rd gen, but I suppose it's possible. Good news is an '86 305 3rd gen pan will fit a '92 truck 350.
You'll have to swap over your 305 flywheel to the 350. Most likely the 350 had an automatic behind it, so that was probably a given, anyway. But the good news is being an '86, the flywheel will swap over to the '92 350 (if your car/engine was an '85, that wouldn't be true). You'll also need to use your 305 starter.
If you want to avoid the intake hassles moving it from the 305 to the 350, use your 305 heads as well. The truck heads are terrible, and as-is, your 305 heads are better. The truck 350 has dished pistons, so the smaller combustion chambers of the 305 heads will give you a bump in compression ratio. They would be even better if you took the 305 heads to a shop and have them install 1.94" intake valves (and better valve springs while you're at it). But, if all that seems like too much hassle, just elongate the intake mount bolt holes like sofa said. Or, get an aftermarket intake for '87-up heads.
Other than that, anything that is attached to the 305 engine, swap it over to the 350 (water pump, distributor, alternator, power steering pump, sensors, etc., etc., etc.).
You'll have to swap over your 305 flywheel to the 350. Most likely the 350 had an automatic behind it, so that was probably a given, anyway. But the good news is being an '86, the flywheel will swap over to the '92 350 (if your car/engine was an '85, that wouldn't be true). You'll also need to use your 305 starter.
If you want to avoid the intake hassles moving it from the 305 to the 350, use your 305 heads as well. The truck heads are terrible, and as-is, your 305 heads are better. The truck 350 has dished pistons, so the smaller combustion chambers of the 305 heads will give you a bump in compression ratio. They would be even better if you took the 305 heads to a shop and have them install 1.94" intake valves (and better valve springs while you're at it). But, if all that seems like too much hassle, just elongate the intake mount bolt holes like sofa said. Or, get an aftermarket intake for '87-up heads.
Other than that, anything that is attached to the 305 engine, swap it over to the 350 (water pump, distributor, alternator, power steering pump, sensors, etc., etc., etc.).
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