Hurst Olds Project; Poll

Which Engine to swap into a Hurst Olds

  • small block Olds

    Votes: 10 35.7%
  • LC2, GN

    Votes: 10 35.7%
  • other, make a suggestion

    Votes: 8 28.6%

  • Total voters


Active Member
Aug 21, 2002
So my fiancee bought me a well used 1983 Hurst Olds. It is complete but the engine knocks.
The interior is ok, needs a carpet and headliner. Paint is all checked and cracked on the top layers, front fender is dented badly, rest of the body is straight.

I am trying to pick a route to go with the engine. I am in the Bay Area so I still have to deal with smog.

Easiest would be a small block Olds swap, a nice 350 or 403 would be ok.

An LC2 would be sweet but not sure if putting one in a Hurst is the right thing to do. (I did this swap in my Cutlass so I know what's involved).

And open to any other suggestions. While I like the LSx motors I really don't want to put a Chevy in it.
I just bought an '06 GTO with the LS2 in it. Other than nitrous, its expensive to get serious hp out of these things - $5-7k minimum for forced induction. While I love driving it and its reliable, it doesn't compare to turning up the boost 10lbs and adding an alky kit to get another 100-150 hp.
My bud just picked up a 84 H/O off of ebay and over the winter and summer he has being swapping parts and building it up.

He put in a 355 Old rocket in it with a Big cam, head work, ported and matched alum intake manifold, headers, MSD ign, etc.

He had a BF trans from a 85 T Type already strongly built from another project and he went through the OZ (H/O) Valve body and modded it and then slapped it on the BF trans with the OZ governor also. Wnet with a non l/u 10 " 3400 stall.

Rearend is getting a new posi unit as the original clutches are done.

If it was me I would go with the LC2 due to the total package, less weight in the front of the car, the gas mileage and it would be turbo!!:cool:

Its up to you ....but....Die hard olds mil bubble fans will say leave it Olds powered.
Motor keep it Olds

70-72 W30 455 442 or that hi-po 70-72 Olds Rocket 350 that came in the W25 Cutlass. That Olds 350 was potent..or the 400 that come out the 69 442. Mondello is the way to go...hypothetically Now how would they do an emissions on a 83 with a 70 Rocket 350 motor would they still test it as an 83 with all the smog equipment, so if it didn't have original smog equip. hooked up you couldn't pass? Maybe just rebuild the engine in it and trick it a tad/mild Hi-po so it can breath, build it so you can run it hard and on pump gas and then you have all the smog equipment that went for that model and year.

You've taken the Buick plunge before you can do the swap again and be well within Cali emission standards and have power to boot.
Legally it can't even have an older model engine than the car; for example 350 Olds wasn't available so it can't go in. Technically it's a V8 going where a same make V8 was so they won't even look. It will still have to have the smog equipment, etc. I am wondering how to overcomplicate everything and add efi to it while looking stock (like a TBI setup to replace the carb). Supposedly the ecm can handle a mild 350. I just need to figure out how it all works. It seems tha the ecm really just controls the carb and timing.
Anyway, I am leaning towards Olds mill but that 307 is never going to cut it.
The 455 Olds is taller and a good bit heavier. You'll probably need at least springs and a radiator. The good news is that small block and big block accesssory brackets all interchange except for the AC. For what its worth, a 403 is a very strong runner if built right. The blocks are weak (window web blocks) otherwise they'd be a fine roundtrack motor. The bore is massive but the stroke is the same as the 260,330,350. All the same crank. 403s need better heads. Early 350 heads, 72 and older are the ticket. Hi-compression 68,69,and 70 heads are ideal if you can find them. Stock 403 has around 8 to 1 compression and aftermarket slugs are pricey. I saw a 403 powered 84 H/O at the H/O Nats at Maple Grove several years ago run low 12s, high 11s and the guy drove it in from way down south somewhere. Impressive ride. Big bore, short stroke....they like to rev but keep the rpms under 6000 because of the weak main webs. I've done one of these before in a 77 Cutlass Salon and even in that tank the 403 was beastly. Had 2.41 gears and very few things could touch it on the open road. Only major defeat was a V12 Mercedes....damn
The radiator would be replaced anyway if I do a new engine and springs will be too, it's gottat sit a little lower:wink:
Did 72 Heads have smog provisions? I know I can get it to pass the tailpipe test if it runs right and keep it mild, just have to worry about the visual crap.
I've done 455 & 403 swaps and you can't go wrong with either.

If you want to keep the stock look with all the emission controls go with a 403. Direct bolt in & you can retain ALL the emissions equipment. Edelbrock has a nice EGR intake & the electronic carb can me modded to give good performance.

The 455 is an easy swap but you will need the ac brackets from a 455 as the engine is a little wider. Tons of torque available & outperforms a built 403 in STOCK form.