Engine swap for 84 Cutlass supreme, 307 to new 350 Chevy Blue Print.

Apr 22, 2023
Preparing for my first engine swap on my 84 Cutlass Supreme. It has a 307 that I’m looking to swap for a new Blueprint 350 Long Block. Right now I’m in the very early planning phase. Trying to learn everything I can about what the swap entails from anything online, YouTube videos and small advice from my grandfather who lives 2 states away. Hopefully some advice and knowledge from some of the Gbody guys in this forum. This is definitely the biggest challenge of my very early mechanical journey with this Cutlass. My father had all the advice I would need about this project. He had a lot of experience fixing up Gbodys. He passed last year, and in a way this car is for him. I realize this will not be an easy task, definitely expensive and time consuming but, I’m only 29, good job, no kids, and an amazing wife that supports my dream. I have the time, I’m hungry to learn, and I’m fully determined to see this job through. Sorry for the life story. Im new to the site and I figured I’d be up front about my situation and my project. Any help, advice, or knowledge would be truly appreciated. Thank you.


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Oct 14, 2008
You need quite a few parts, Olds and Chevy V8's have little in common. You need the frame mounts with the matching sbc motor mounts, accessory brackets for a sbc, exhaust is different and you may need a trans adapter, if your trans isn't a dual pattern. Is it a 3 spd or overdrive transmission?


Aug 8, 2011
I have done the swap quite a few times and most recently on my 86' Regal going from a 307 to a 355 SBC.

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You will need to source engine mounts for the frame and engine for SBC, they are available new or used, I always buy new frame mounts since they are very inexpensive.

If you are keeping your transmission and it is a B.O.P, then you will need an adapter to mount it to an SBC.

You will have to get an accessory drive kit either V-belt or serpentine, these are available used, new and aftermarket or you can fabricate a kit like I did.

If you are running headers and dual exhaust you can buy a new double hump crossmember or modify your existing, I have the Jegs 200R4 in my Regal and it fits well.

You will need to move the wiring for the starter over to the passenger and I also moved the battery to that side and made new cables.
And if you do run headers I like to run a remote starter solenoid so that the battery cable going to the starter only has power when cranking.
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G-Body Guru
Supporting Member
Sep 27, 2021
Mesa, AZ
Welcome to the GbodyForum!
I did an engine swap to a Blueprint 383. I purchased the dressed version to have it most complete. Although I was able to use my front drive pulleys, This will at least allow you to start with the most complete kit you can. Blueprint does offer a pulley drive system but it was not in my budget. As 565bbchevy mentioned, the front pulley drive accessories are available everywhere. I've been happy with my Blueprint Engine so far however, they are a little expensive. But do come with a warranty.

Good luck with your build. We are here to help and assist. You have a nice looking starting point.
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