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V8-350 Swap 92 Astro

24791 Views 60 Replies 14 Participants Last post by  gwd
The old 4.3 in my 92 Astro made it to 282,000 original miles! A recent tick that developed into a knock turned out to be a broken piston skirt...not sure how it happened. Oil pressure still strong.

I'm swapping with a 350. I have no intention of using the computer. The 350 engine is carbureted, and is originally from a very low mileage 70 Caprice. (No emissions in Fla) The engine has a nice rumpity-rump high torque cam and intake installed, gets great mileage and runs AWESOME!

I have already purchased the custom swap V8 motor mounts, and Hedman shorty headers.

Here are my initial questions:

1) I assume the only issue with the 700R4 will be the lock-up converter (assuming I want to use it)? I've been told to either add a toggle-switch, or possibly a vacuum switch to operate it... assuming the converter is sufficient to use behind a V8? (I have a nice new TH350 with B&M 11" Holeshot converter, but I think I'd miss the overdrive).

2) The stock A/C system runs on a serpentine belt, the older engine is V-belt of course. I assume I will need to swap water pumps with a proper reverse pump that will work with serpentine system. What pump will I need? Will the V6 pump interchange? I'm assuming the powersteering and alternator will bolt up ok?

3) I also assume I will have to do something with the cooling system, fan, shroud, radiator, etc.

I will be pulling the motor from the front (working in my home garage)

The motor will be naturally aspirated (carbureted)... using HEI distributor. Fuel delivery will be stock system, with a regulator.

The other mods seem fairly obvious to me. I will have ALL the accy's available from the stock V6... if any are needed and can be used.

I have been waiting for many years for the V6 to finally die, the V8 has been patiently waiting! I just couldn't bring myself to pull a perfectly good running engine... but now the time has come.

I plan to run full dual exhaust as well.

I know there is a wealth of info here on this site... which I will be reading. I'm excited about my new advanture... as I have been a hot-rodder all my life! My last G-van had a supercharged 502. This current V8 was in my '69 Chevelle convertible.

Now it's the Astro's turn for an upgrade! It's a shorty with wide-tires and Centerline rims... and should be a perfect match!

Thanks for any advice and suggestions!
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The old 4.3 in my 92 Astro made it to 282,000 original miles! A recent tick that developed into a knock turned out to be a broken piston skirt...not sure how it happened. Oil pressure still strong.

I'm swapping with a 350. I have no intention of using the computer. The 350 engine is carbureted, and is originally from a very low mileage 70 Caprice. (No emissions in Fla) The engine has a nice rumpity-rump high torque cam and intake installed, gets great mileage and runs AWESOME!

I have already purchased the custom swap V8 motor mounts, and Hedman shorty headers.

Here are my initial questions:

1) I assume the only issue with the 700R4 will be the lock-up converter (assuming I want to use it)? I've been told to either add a toggle-switch, or possibly a vacuum switch to operate it... assuming the converter is sufficient to use behind a V8? (I have a nice new TH350 with B&M 11" Holeshot converter, but I think I'd miss the overdrive).

2) The stock A/C system runs on a serpentine belt, the older engine is V-belt of course. I assume I will need to swap water pumps with a proper reverse pump that will work with serpentine system. What pump will I need? Will the V6 pump interchange? I'm assuming the powersteering and alternator will bolt up ok?

3) I also assume I will have to do something with the cooling system, fan, shroud, radiator, etc.

I will be pulling the motor from the front (working in my home garage)

The motor will be naturally aspirated (carbureted)... using HEI distributor. Fuel delivery will be stock system, with a regulator.

The other mods seem fairly obvious to me. I will have ALL the accy's available from the stock V6... if any are needed and can be used.

I have been waiting for many years for the V6 to finally die, the V8 has been patiently waiting! I just couldn't bring myself to pull a perfectly good running engine... but now the time has come.

I plan to run full dual exhaust as well.

I know there is a wealth of info here on this site... which I will be reading. I'm excited about my new advanture... as I have been a hot-rodder all my life! My last G-van had a supercharged 502. This current V8 was in my '69 Chevelle convertible.

Now it's the Astro's turn for an upgrade! It's a shorty with wide-tires and Centerline rims... and should be a perfect match!

Thanks for any advice and suggestions!
View attachment 284704

EDIT: FIX MISSING PHOTO
I wound up on the S10 going to scrapyards till I found one with all the belts intact, showing me everything was there. Those JTM mounts are the shit, but I had to add some to the driveshaft. But yeah, carb. and adjustable pressure regulator, plus HDI is about all ya need to get 'er driving!
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