V6 to SBC Swap


Master Mechanic
Apr 24, 2006
Indy, IN
I thought that I posted this already, but don't seem to find it. Hope it helps.

Parts Needed For V6 to SBC V8 Engine Swap
*Unless Noted Otherwise, Parts Can Be Had From 1978-1988 305 Monte Carlos*
*Please Use This As A Guide Only, I may Have Forgotten A Couple Of Parts. You May Already Have Some Of The Needed Parts From Your Current Set-Up*

1. Engine - Small Block Chevy (SBC) 305, 350, 400, 383, 327, 307, 283....
2. Transmission, Flywheel, Driveshaft (All Compatible With Engine, Crank, and Rear Differential)
3. Trans X-Member (Compatible With Trans And Year Of Monte Carlo)
4. Transmission And Motor Mounts - GM Clamshell Mounts & Steels For Engine Block, Trans Mount For Transmission Chosen (Motor Mount Steels are available on many Mid 70s-Late 80s GMs)
5. Engine Sheet Metal and Hard Parts for the Chosen Engine Year (Intake Manifolds and Sheet Metal vary from some years to other years) - Timing Cover, Oil Pan, Valve Covers, Intake Manifold, Exhaust Manifolds or Headers (Exh. Manifolds and Y-Pipe will hook up to existing Exhaust with Less Hassle), Non-Computer Controlled Carburetor, 4-Pin HEI Distributor (Non-Computer Controlled), Starter (Compatible with Engine and Trans)
6. Fan Shroud, Fan Blade, Fan Clutch, Radiator, Water Pump, Radiator Hoses or Electric Fans and Shroud from 307 Cutlass
7. Front Engine Accessories - Re-Use Old Accessories from the 3.8L 229 Chevy V6 and 4.3L TBI Chevy V6. Need New Front Accessories for the 3.8L 231 Buick V6 (Distributor is Up Front on this Engine) - Many GM V8 Cars and Trucks have Donor Accessories, Serpentine Systems are Compatible also.
Stock Monte Locations are Alternator at Top/Passenger Side, Power Steering at Botoom/Driver Side, and A/C at Top/Driver Side
8. Fuel Pump
9. Wiring Harness or Cut Your Existing Harness to Fit
10. Air Cleaner
11. Front Coil Springs - To Support the New Weight
12. Thermostat, Temp Switch, Oil Pressure Switch, Miscellaneous Vacuum Line and Fuel Line - Temp and O/P Switch Need Matched to Gauge or Lights and Threads on Engine
13. Tune-Up Parts - Spark Plugs, Spark Plug Wires, Distributor Cap and Rotor, PCV Valve, Fuel Filter
14. Fuel Pressure Regulator if Re-Using Original TBI 4.3L Gas Tank and Fuel Pump
15. Transmission Shift Cable and Detent Cable (Kickdown Cable)

Work Needed For V6 to Small Block Chevy V8 Engine Swap

*Not Every Detail is Listed But Will Get You Started on Replacing That Weak V6 With a Stronger V8*
*Most Of The Job is Pretty Straight Forward*

1. Start By Disconnecting The Battery
2. Remove Hood and Stand Out of the Way
3. Drain Antifreeze, Oil, Trans Fluid, Power Steering Fluid
4. Remove Fan Shroud, Radiator, Engine, Trans, Motor Mounts, Power Steering Hoses
5. Lots of Clean Up and Painting
6. Install Motor Mounts - Clam Shells go on Frame with Lower Forward Bolt Hole Hanging Off the Engine Cradle
7. If You are Replacing the 3.8L Buick V6 Run New Fual Lines on the Passenger Side - Chevy Fuel Pumps are Located on the Front Passenger Corner of the Engine
8. Install the Engine and Trans - Start Installing Engine Accessories at this Time, Gap The Spark Plugs for the Type of Distributor You are Using (Points or HEI)
9. Install Radiator, Fuel Pump, Carburetor, Exhaust, Starter, Transmission X-Member, Fan Shroud and Fan, Power Steering Hoses ( Check For Correct Hose Fittings First)
10. If Using 4.3L TBI Gas Tank and Fuel Pump, Install Fuel Pressure Regulator Set at 7-9 PSI for Carburetor Use
11. Add Oil and Prime the Engine if Engine is New or Rebuilt
12. Add Trans Fluid, P/S Fluid, and Coolant - Check For Leaks
13. Hook Up Fuel Lines, Starter Wires, Alternator Wires, Elec Choke, Distributor Power, Oil Pressure and Temperature Switches, Vacuum Advance
14. Set Timing by Adjusting Distributor
15. Bleed P/S and Remove Air from Cooling System, Top Off Trans
16. Reset Timing and Enjoy
17. Double Check For Leaks - Fuel, Oil, Trans Fluid, Power Steering, Coolant
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Aug 14, 2006
I just pulled the motor out of my 85 Grand Prix, and the starter looks similar to a sbc starter. Does anybody know if i can use it on my 350?
Sep 1, 2006
Tampa Bay Area
Was it a Chevy or Buick V6? If Buick, I believe no. If Chevy, probably as long as they have the same flexplate ring gear tooth count. (Early SBC has 168 teeth, late has 153. Changed around 1980 IIRC)


May 29, 2006
there were both sbc flywheel diameters in same almost all years

in the 80s there were both

before that there were both too, espcially on the 70-80 400sb engines

years had nothing to do with it

for the fuel line if i replace the 231 with a sbc i am just going to extend the line across the engine cradle to the other side

olds and buick and such used reversed starter nose cones than chevy did

the battery on the wrong side of the engine bay is the first clue that the starter nose will be wrong

swap it with another nose

same motor housings

unless it is the small motor housing diameter(sometimes but not as common as the larger ones)

it is cake walk to swap a starter nose cone

no need to swap the bendix/drivegear, they are the same regrdless of flywheel diameter

good luck
Sep 1, 2006
Tampa Bay Area
No, they changed the flywheels when they switched from a driver's side to a passenger's side dipstick. This is common knowledge. There are other minor block variations over the years, but I did not list them all since it is unlikely most people will encounter them. Most are from 50's and 60's engines and those engines are somewhat rare these days. The 400 only used the 168 tooth flywheel and not the 153. Go try to buy a 153 tooth 400 flywheel or flexplate-they do not exist as a stock application. I know this from experience and having to have a neutral balance 153 tooth flywheel rebalanced to the 400's specs to run it with a BW T-5 in an 84 Camaro.


G-Body Guru
Oct 24, 2007
Lakeland, FL
You can re-use the starter.

Buick starters will interchange with chevy small block. I run the chevy mini-starters on my Buicks when I build them.

Olds/Pontiac starters have the nose cone reversed for mounting on the driver's side of the engine.

Silent viewer

Royal Smart Person
May 9, 2007
i agree, you can go to advance autos website and look up either starter and click on see other vehicles this fits and it will show that they are the same.... i just recently learned that one. and to thinki have been trashing all of my 3.8 starters!


Apr 6, 2009
Just about ready to pull out my 4.3 out of my monte & drop in the 350.

looking for a clear answer with the motor mounts, are the 4.3 the same as the 305-350 etc. etc. or do I need to find some from a V8

the mounts on the frame & the mounts on the motor?


Master Mechanic
Oct 7, 2005
Evansville, IN
St.Pete_MC said:
Just about ready to pull out my 4.3 out of my monte & drop in the 350.

looking for a clear answer with the motor mounts, are the 4.3 the same as the 305-350 etc. etc. or do I need to find some from a V8

the mounts on the frame & the mounts on the motor?
they are different, you will need new frame and engine mounts for a V8

Silent viewer

Royal Smart Person
May 9, 2007
i am not 100% sure but i think the 4.3 and a sbc share the same frame side mounts on a g body.....

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