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nova 250 6cyl to 283 V8 swap

4K views 5 replies 5 participants last post by  johnnya 
#1 · (Edited)
Hi, I just got a 1976 Nova w/ a 250 6 cyl that runs for $150. I also have a 283 from a 1958 Chevy that runs for either $150 or $200, don't remember, and am seriously considering putting the 283 in the Nova and would like to know what is involved and if it's a good idea. Also read a great story on this 283 engine on page 2 of my thread called new to hotrodders.com. :welcome:
 
#2 · (Edited)
Sounds like an excellent idea. I changed a '69 Nova from a 250 to a stock '59 283 w/4-bbl, and it was well worth it. I had a '77 Nova w/250, and it was a dog compared to the '69 w/250, so the 283'll likely make you smile.

Use motor mount plates from a '75-'79 Nova 305 or 350 car. The rubber mounts that bolt to the frame are the same for 6 or V-8.

Use the trans, flex-plate (flywheel), and starter from the 6. Mine used the smaller 12-3/4" flywheel with 153 teeth, and the starter has mounting holes that form a line perpendicular to the centerline of the starter motor. The '50s cars used starters that bolted to the bellhousing, but the Nova starter is bolted to the block. My 283 block had the outer hole for the late-model starter already drilled and tapped, while the inner hole was there, but not tapped, so I had to tap it myself. If your starter has the angled hole pattern, you may have to drill and tap a whole new hole.

Use a fan shroud and the plate that holds the radiator down for a '75-'79 V-8 Nova. You may have to space the fan forward an inch or so if the old engine has the typical-of-the-era short water pump. '70s cars used a long pump.

You may have to engineer your accelerator linkage, but somebody like Lokar might have something you can buy to fit it.

Ditto the accessory brackets, since the old car had a generator instead of an alternator, in addition to the water pump differences. '70s V-8's heads have accessory bracket holes in the ends, but the old heads don't. They can't be added without risking ruining the heads.

Exhaust, obviously, needs some work.

If you use a points-type distributor, use the ballast resistor (AKA coil resistor) from the old car in series with the distributor power wire. If there's not one, tell the parts store you need one for a '57 Chevy Belair with a carburated 283. Without it, you'll burn up the points way too quickly.
 
#4 ·
I did the same swap in 1984 in a 76, used a 327 300 hp thought it had a big cam because of the idle, turned out later to be wiped cam, swapped in early camaro 12 bolt with 3.55 gears. Ran 15.0 on crappy hard remington xt 120 radials burning the hides off.Also delivered over 20 mpg on the highway with a Qjet. Not a bad first high school hotrod. I loved it .
 
#5 ·
I don`t recall what year GM started to place side motor mounts on the blocks, so you might want to check your 283 and make sure it has them.
If the 283 has been sitting a while, when you have it dropped in and ready to fire off, cycle it as if it were a new engine, do the same procedure you would as if you were breaking in a camshaft. If it`s not cycled the cam will go flat. 1800 to 2300 rpm in 5 minute varibles for 20 minutes should be all it needs. I would also pour in some stp oil treatment to be certain it has all the anti wear additives it needs which are missing in todays oils. If the 283 hasn`t been built, while it`s out I would install a new double roller timing chain, a aluminum dual plane intake and a Quadrajet carb. Not only will this give it some pep, but you`ll knock off outstanding mileage as long as the tune up is in good shape. Good luck with your swap.
 
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