1983 Hurst/Olds 307 V8

I had a few questions about my 307. What is the highest i could bore a V8 307? Also what can I do to make the V8 307 put out more horse power and torque? I have about $3,000-$4,000 to spend. Plus I have to get it running its been sitting for maybe 15-20 years.


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You got that kind of money don't waste it on a 307 Olds. These are great work horse engines and they last a long time, but there are little performance pieces for it. By '86 they came with roller cams but it didn't help much, as the head ports are really small. The few performance pieces for it such as headers, real small cam, intake will get you to to about 200 horses. This is why you never see anyone trying to hot rod a olds 307 as theres no market for it. Your car is a valuable car and you want to keep the original plant then the best recommendation I can give is put the 307 in storage and build a Olds 350.

Will a gm 350 fit the engine mounts in the 1983 hurst/olds? I was looking at crate engines on Jegs.com, and they have some nice 350 crate engines that put out 300 and some hp.

"....Will a gm 350 fit the engine mounts in the 1983 hurst/olds?...."

No, the mounts are different and unless the transmission has the multiple bolt pattern (BOP and Chevy) you will need a different trans. As a G Body however, the frames are drilled for the correct mounts and it's pretty mucha bolt in swap.

While you're digging up the parts you might as well order some big bowtie decals to throw over the H/O decals that are currently on the car. One of the neat things about the H/O was that they used an Oldsmobile engine.

With the budget you have a 350 Olds or better yet a 403 (which is the same physical size as the original motor) is definatly doable. Even in stock form a 403 would turn the car into a monster.

If it has the original OZ code 2004R Trans it will have the UniBell which bolts to BOPC/Buick,Olds,Pontiac,Cad & Chevy Engines.

Plus, i think you have the 8.5" 10 bolt. Lucky you.

Swapping in a Chevy 350 is a breeze. I've did it on three Cutlasses now, Two '84 models and one '86. The '86 was mine and it was the only one of the three that came with a V8 which made the swap easy as a TH350 trans was a bolt in. As mentioned the frame is drilled to accept chevy mounts so all you'd have to do is buy some and bolt them on. The clam mounts that bolt on to the side of the block I recommend getting off a chevy truck. The first time I did my swap I used the clams off a Monte Carlo, which you would think being a G body, the engine would drop in and sit correctly. It dropped in fine, but the front of the engine sat up too high which put the weight towards the rear of the car and as a result the front end sat up like it had coil spring boosters on it. When I later did the rebuild I got some clams off a chevy truck and the engine sat down nice, low and level. You will have to make some changes by going to the chevy engine. One of those changes is the battery and starter are on the drivers side on the Olds engine. On a chevy engine its on the passengers side. You would have to remove the carbon canister that rides in the passenger battery well. This will force you to leave the vapour line open as if you make the mistake I did which was plug it off you'll have nothing but endless fuel pressure problems from pressure build up in the fuel tank. I never did find anything I could plumb the line into as I didn't like leaving it open as the fumes made it unsafe. You could move the canister over to the drivers side and use some 5/16 hose over to it by routing it into the front clip in front of the radiator. Also keep in mind you won't be able to use the computer and CCC system currently on the car so you'll have to use a non CCC operated carb and a older HEI with mechanical and vacuum advance. If you plan to keep the CCC system you'll have to find a place under the hood to tuck in the mess of wires. The A/C wires and Alternator wires are all long enough to work on the Chevy engine but they'll need a little rerouting. If you plan to use the A/C in the car then I would find a Serpentine system off a Early 90's camaro or chevy truck. Then you can use the lines off a late 80's early 90's camaro and use the lines. You'll also need the dryer which you can get at the parts store. Why I recommend this as if it's ran to the drivers side the hoses are a mile long and they get in the way. Moving them to the passengers side cleans up the underhood area considerably. Thats about all I can remember to mention to make the job easier for you but I'm sure I'm forgetting something and I likely am. Anyways, if you need anymore pointers just ask as I just about remember all the steps to building a Cutlass. One last thing, the vacuum lines that operate the vent system in the car make sure you mark them and what they were connected to as I had a PITA trying to figure mine out. With the cash you got you could easily buy a used running chevy Vortec 350, do a basic ring job on it, have the heads worked and guides clearanced for increased lift, install a larger roller cam and a Vortec intake and easily make 300 horsepower and you could do this for far less than buying a crate engine.

I actually found a guy who rebuilds oldsmobile engines. I got a price on a 403 crate engine, under 5k. What do you guys think.

Belly-button SBC swaps are BOOOOORING. The 403 Olds drops in and is much more interesting. Besides, this is a Hurst/Olds, not a generic Cutlass.

X 2 what Joe said , find an OLDS motor for it, Keep it oldsmobile A hurst Olds with a SBC would be Ho Hum.

I had a 350 in my '42 Chevy. It was a stock 1974 engine with a Performer intake and carb. Fun to drive and it was one of the lowest horsepower Olds 350's. I had friends ride in it and they all were surprised by the power it had. I had them tell me they thought Olds engines were slow. They were wrong. Good luck.

Go 403, my brother had a 73 cutlass with a 403 stock and this thing would fly. He had the stock 14in rims and this thing would blow the beauty rings of the rims. keep it olds

83 H/O has the 7.5 rear axle, the 8.5 wasnt used until 1984.

Who did you find to build your 403, theres at least a half dozen legit Olds shops around the US that can build one correctly for you. Just make sure you know what youre getting for your money.