V6 to SBC Swap


Jul 26, 2014
I know im a little late to this party.

The 4.3 uses the same block and frame mounts as the small block and even big block chevy motors.been a whil. Since ive seen a gbody with a 4.3 to know where the frame mounts go but IIRC you pop the 4.3 out and drop your small or big block right in.


Apr 3, 2016
I need help in what position on the frame does the motor mounts (V8 350) attach to... A picture will help thanks
  • Optimistic
Reactions: 1 user


Aug 8, 2011
I stole this picture from L67ss. As you can see you only use 3 of the 4 mounting points for the Chevy engines
  • Like
Reactions: 1 users


Apr 3, 2016
Thank you very much this is clear.... I have a question. My v6 has AC, do you think I have to completely remove the AC compressor or I can just put it aside for removal?

V8 Rumble

Royal Smart Person
Jan 7, 2010
Thank you very much this is clear.... I have a question. My v6 has AC, do you think I have to completely remove the AC compressor or I can just put it aside for removal?

If you're going to v8 you may have to change the hoses. If you can set it aside without binding you can put it aside to avoid discharging it.


Jul 2, 2019
I'm doing an 85 monte carlo swapping v6 for 350 sbc what all needs to come out and what do I keep in there


Jul 2, 2019
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
So everything right here is step by step or have you updated the list just asking getting ready to do this as we speak on it


Feb 11, 2022
Was this swap worth it? As in, noticeable difference? Depending on the headers you went with on that 5.7, you likely went from 150HP to 240HP. 5.7L engine horsepower is all over the place depending on the heads.

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact [email protected] for info on becoming a sponsor