The 425 is a great engine with plenty of torque. There is not much in aftermarket parts around like for the 455. My brother's '67 Olds has a 425 and is still going strong with orignal miles. Is your engine complete and running? If so and you decide to let it go, get in touch with me. Thanks
i only know a little, maybe someone can clarify this, the 425's are a shorter stroke 455 with a steel crank, and the cam is different than a 455, which gives it less readily available cam choices, add iv heard the lifters cost alot more than a 455, but the shorter stroke would let it rev out a little more no?
i think your right on all counts. years back i built one for a 75 cutlass i had reed cams grind a cam for it with rhoades lifters. it wouldnt rev very high but could pull the side off a house under 4000. biggest trouble was at around 10.5 to 1 comp, finding gas that wouldnt ping...
The Toro engines were higher compression than the RWD versions, I had '66 Starfire, and it had a 10.25:1, and it was rated a few HP less than the Toro 425... I would guess the '67 was the same, 'cept no Starfire to compete with.
The 425 is, in my op, the best of the big block Olds motors. Yes it has the shorter stroke and a bigger bore. Will wind quicker that a 455. Has a forged crank in all of them and pistons are $$$. Any 455 speed parts will bolt on, heads, intakes, headers, ignitions, and some cams. The lifters are a larger diameter than 455's but this gives the cam ramp some advantage. Not all 425's have the odd cam bank angle. See another post here about a 455 big block a guy had a question about for good websites to get more info.
I put close to 100,000 miles on my 67 Toronado, and never had a hint of trouble with that engine and tranny combo. That two stage torque converter was something that really helped that car move when the traffic light changed to green. I just loved that car. Bob
Like Oldspert and Tindall said the 425 is the best stock big block Olds. Not only does it have the shorter 3.975 stroke it also has the longer 6.998 rod. I think the 67 Toro motor your looking at has the larger .921 lifters with the later 39 degree angle. The intake sucks[very low profile for Toro hood clearance] but good intakes are available. I believe speedway even had a dual plain high rise air gap intake available. It will run good stock but with a cam and intake it will really come to life. It will rev much better than the 455 but the stock cast pistons aren't the most durable when hammered on and good forged replacements aren't cheap.
Great motor. Lots of torque and is oversquare. Toronado motor rated at least 10 HP higher than the 425s used in other Olds models. Forged crank and high nickel content blocks. Tough moter, they can handle abuse.
if its truly a Toro motor, it has the later 39 degree lifter angle which means any 455 cam will work and the "B" heads are fantastic!! I built my 66 Toro 425 with an extreme energy cam, B heads with hardeneds seats, bigger springs, rollers rockers, a tunnel ram with a Holley 750. Talk about an awesome sounding, high revving stump puller!
Will fit any Turbo Hydramatic with the Buick/Olds/Pontiac/Cadillac bellhousing if you want RWD. Years ago a friend of mine put one in a Camaro, it was crazy fast, more like a big block in performance but not much heavier than a small block.
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