Looking for those of you who are or were driving an 425cui Olds... I aim to buy one (65 Starfire), and would like to know your experience!! What are its weak points, and what are its vantages?? Would be very happy, if you'd share something!! Thx in advance EDIT: Just aiming to buy the engine for my 35 Ford Truck!!
great engine, lots of torq and hp.....it has 45 degree bank angle,this will need to to you cam supplier if you purchase a cam...
great motor. not all of them had the funky lifter angle- toranados were the norm, as best as I can tell.
Pro's: Forged internals Good RPM's Good HP GREAT torque Cons: Gas hog Different models durring production run Parts are hard to get I cant really say anything that would cause you to go with or avoid this particualr engine. I'v owned 2 of them, both in full sized stockers. I remember them as strong reliable motors that would move 2 tons of steel with ease and light up the tires with little more than a tickle on the go pedal... But I also remember they were gas hogs. Speed parts might be difficult to come by, so if your gonna hot rod it, look into what's available before you buy it, otherwise it should make a good choice.
I am building a 425 to replace my 455 in my old truck, so I have done a lot of research on these. 425's have forged cranks and rods, a shorter stroke than the 455, cast pistons, and early heads that need hardened seats. They are mostly 45 degree blocks- cams today are made for later blocks that are 39 degree blocks- so you will have to have a custom cam made probably. Not a biggy, you just won't get it at Autozone. There are two different diameters of lifters, the larger ones are more desirable from a performance standpoint but are also more expensive. The rockers are not adjustable but can be made adjustable with some aftermarket pieces. Rebuild parts (stock) are still around- no problems with that. Aftermarket parts are few and far between (compared with Chevies and Fords) with most parts being custom (pistons, cams, etc.) but there are parts that you can steal from other engines. For example, aftermarket rods can be gotten from a Caddy. (One of the common mods of Caddy rods is to use 7" Olds (425) rods in them- **** makes aftermarket ones for this application that will work.) Rear main seals from a 460 Ford are a good choice to replace the stock rope seal. Rusty
I missed mentioning the weak points-1) oil system is marginal but can be upgraded, 2) the bottom ends of the blocks are weak- if you plan to exceed 450 HP, some mods will have to be done. If you want, I can give you some Olds specific vendor names.
Hey guys!! Thx for you replies, the is very much information I will need!! I will not hot rod this engine, means I am not looking for all these "speed" equipmment. I just want to use it as stong stock engine. So the only parts I will be looking for are stock parts, that from time to time need changing!! Rusty: would be very nice, if you could name me some vendors!! Pir8Darryl: I am originally from Austria, where the gallon of fuel would be about 8$... So I am not really into this "gas is so expansive here" thing... But thanks for your input!!
I have found memories of the 425. I first got into cars when I was like 4 or so and my parents had a 1967 Olds Delta 88 and I thought the engine was so cool looking. I remember it being red and said "425 Rocket" on the air cleaner. My uncle had the same car when he was a teenager and I remember him telling lots of street racing stories from back in the day. That car moved pretty good more being a tank. Anyhow, gay story, but I always loved that car and that engine...
If you are also using the turbo 400 trans from the Starfire be sure you hook up the switch pitch torque converter which these transmissions had.
A friend of mine has a 65 Delta 88 with the 425 and less than 40,000 original miles on it. My dad has a 96 Impala SS and the Olds beat it from a rolling start, the Impala couldn't catch it either! I'd really like to buy that car sometime as its really a great looking car.
I'm running a 1965 425 in my model a pu. Some parts are very hard to find. Looked for a manual flywheel for about a year. I can't seem to find anyone willing to make me a set of zoomies or lake headers due to the huge rectangular ports. Definately a gas hog. Burned up 5 gallons of fuel in no time just tuning my dual quads. Can't wait to get it on the road to feel the torque everyone talks about.
fuxl- Try Egge, Inc. at www.egge.com for stock 425 parts. Occasionally you can find parts on Ebay, but be careful and do some shopping before you buy there- some folks claim "rare" and sell some non-existant parts. You might also try Performance Automotive Wholesale (www.pawengineparts.com) for most stock or mild hot rod parts. If you are interested and don't mind cutting thru all the BS, try www.realoldspower.com. You can occasionally find some parts over there and those guys are dedicated to Oldsmobile. There are several people over there with Starfires on that site and can help you find parts for your car. Other performance dealers (even though you don't plan on hot rodding it): **** Miller Racing Rocket Racing J & S Machine But stay away from Mondello's in California. It used to be run by Joe Mondello, but now it is run by someone else who according to what I have read, doesn't mind sticking it to people. I failed to mention one weakness of the Olds- a small oil pan. If you keep the RPM high- over about 4500-5000 RPM too long, you will **** the pan dry. I have heard of it happening in 455's used in boats, but never seen it happen in a car. Have fun!
One more thing no one has mentioned. You can put all of the piston-rod-crank ***embly into a 455 block. This gets around the odd lifter angle, and you get ot use the cheaper small diameter Olds lifters. Any big block heads, intake, headers will bolt up, dizzys will fit, all sheet metal works, any thing that fits a big block will work on the 425 block or the 455 block. Some people are even putting small block heads on the big block. Makes high compression with stock pistons but can be lowered using dished pistons. Using the motor stock will probably last only about 150,000 or more miles.
Thanks guys for this great information!!! I think I'll need it, but first of all, I have to get a 425 Olds ;-) If there is something additional to say, go ahead!!! one more thing: I found a chart, where it says the 455cui Olds weighs 605pounds... Is this a fact?? So I'd guess, the 425 should not weight more (because I don't want to hurt my suspension)
The 425 might be a little more because of the forged crank vs the cast crank in the 455. Won't be enough to matter.
Not a real popular engine/frame combo. You will probably have to fab some. I am going to make mine from 2" X 2" X 1/4 angle. Since the engine mount bolt pattern is perpendicular to the block, I am going to make a set that bolts to the block leaving the opposite leg of the angle parallel to the frame. Use a biscuit mount and a flat frame adapter and you are good to go.
one thing i've noticed here, is that people say the 425 is a gas hog. maybe i'm being simplistic, but if the carby is tuned stoichio and given comparable exhaust, how is 425 any more a gas hog than a 400, 454, 455, 472, 500 ...? not being a smart ***, just wondering if a factor X exists here. does bore/stroke ratio have any bearing here? not to hijack...
I ran a 425 in my stock car back in the late '70s. I was told by the local engine building guru that side clearance on the rods is critical on these motors. ****ers ran stong, won't rpm like a small block, but all that torque would really launch out of the corner. And nothing sounds as good as a big block!
Is there at least a kit of the plate that bolts to the engine and this plastic cushion?? I thought I have to custom fab the pieces that will be welded to the frame, but would be nice to the other stuff and know it fits perfect...
I don't know of anything that is available from aftermarket. You can get hole spacing from an original motor mount to fab the piece to bolt to the block. It will be simply a piece of angle iron that bolts to the block in the same location as a motor mount. It won't have any kind of angle to it. The bottom side will be parallel to the frame mounts you weld to your 34 frame.
you can get the actual motor mounts off e-bay or go through Kanters. You will have to fab some steel off the frame though. Hard to tell, but here's pics of what i fabbed up to my 425.
That looks good!! So how is the ****** mounted?? are there also two mounts on the side, or only one at the bottom??
While we're on the 425 subject; A buddy of mine did one that was all stock except forged pistons/ balanced, with a cam(hydraulic gets around the non-adjustable thing) and intake, ran like a bat outta hell for ever! Only weak point being that the head is held on by four bolts per cylinder, and that was only a problem when he put a 125 shot fogger on it and ran the snot out of it several hours one night, the next day it needed head gaskets, which cured the problem(till he did it again, then same story)!
These 7" H beams being blown out by a vendor for christmas @$545/set, only a couple sets left. PM me for info if your interested...
There are two sets of holes to mount the original motor mount to. Both use the center hole and use either the right or left end ones, depending on where you need to bolt the motor mount on. Cutl*** size cars used the ones most rearward and most big cars used the two forward locations. The pic of the rust2rich coupe uses the ones in the front location.
I'm running a muncie 4 speed in mine. I had the 400 in it but changed my mind. I just ran a peice of 2'' box from each frame rail across, welded a peice of 1/4'',2x2 angle iron off the front of the box tubing with gussets on the side and drilled 2 holes in the center to bolt to the ******.
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