Olds Engine 64-76

 in the 60’s there were the 330- 400-and 425 early olds engines which had a different lifter bank angle at 45 degees than the later engines . All of them had steel crankshafts. the 400/425 block is basically the same engine block as any of the 455 blocks other than that for the most part. the 330 is a different bore than the later 350 olds engines, however the crankshaft is the same journal and stroke as the later 350 olds engines so you can use the crank out of an older 330 in a 350 for performance. the flywheel pattern is different though.

Although i have heard guys tell me of 455’s in 1968, i am going to say in 1969 for sure that olds shifted production to two v-8 engines. the 350 and the 455. these and all later engines used a  39 degree lifter bank angle- so you guessed it the camshafts will not interchange with the older engines. the cylinder heads will interchange however. similar to chevy some had more performance potential than others, but in this day and age it is kind of a mute point with aftermarket heads available.

obviously like with any auto maker at the time there were factory options with both of these engines. ROCKET350 or ROCKET455 was more of a label than a designation and doesn’t necessarily mean it had more performance than an olds engine without the label. i think it was more of a sales gimick. the 442,w-30, and toronado’s did mix it up a bit. i am not going to keep going into the specifics as it has been a real sore debate with some enthusiasts over what went with what originally.

for the most part, from 1970-76 was the bulk of the oldsmobile V-8 engines that people deal with. those being the 350 and the 455. they were essentially the same but the 455 had more deck height. most of the accesory’s, covers, ignition, and how they mount in the car will interchange. although the cylinder heads were different from small block to big block as far as valving and chamber size, they were identical and would interchange if you have enough patience. the thrust bearing sits at the middle of the block rather than the rear for the crankshaft. firing order is 1-8-4-3-6-5-7-2 just like a chevy, but the distributor rotates counter clockwise and uses a hex key to drive the oil pump. the intake can be removed without pulling the distributor, but it can be a pain in the ass with some intakes. there were also two different timing markers- one for small block and one for big block: even though you can use the same dampener. water pump snout lengths were different, as well as front accessory set ups. pulleys can be a real bitch to get right on just about every oldsmobile i have ever owned.  it seems like they changed the damn alternator and power steering set ups every year from 68 thru 73. they also had both right and left hand alternator positions for non-AC and AC equipped cars.

Now, early 455 blocks are a bit more sought after and are marked with a big old “F” on the block. most of these were from 68-72 although sometimes they appeared in toronado’s all the way up to 76. when i started out into the oldsmobile shit, these were the blocks to have for nickel content. from 72-76 the 455 block had an “Fa” designation and omitted the boss above the starter on the left side which was used for a manual clutch set up. i have been told that the F blocks had more material at the ends where the Fa had more material in the main webbing at the center. to be honest there is no real difference between the two other than the older F blocks are worth more for the clutch boss for 442 collectors. both the F and the Fa block are ultimately the weakest link in the engine when you build performance. there just isn’t a lot of material on the main webbing of the block to keep it from flexing when you start to make big power with performance parts. so pretty much if you have a hard on to build big horsepower and torque with a 455 you need to invest in some kind of a girdle to help support you main caps.

400-425-455 cranks were all big heavy bastards at around 80lbs. all the 400 and 425 crankshafts were steel. some rare few 455 cranks early on were steel cranks, and are worth good money if you get your hands on one. most were a cast iron or a nodular iron. the nodular iron basically is a different casting that allows the crank to flex and take more load. they were marked with an “N,NAK or CN” on the front counterweight of the crankshaft. the nodular crankshafts are preferred and were put in the cars with tow packages or performance oriented from the factory in like a 442. really though, none of these crankshafts will be better than the other as the block will let loose first.

when you start to beat on these big blocks, the first thing to go is the #4 main bearing, which sets off a chain reaction through the bottom end of the engine. since the bottom of the block doesn’t have much for support, that big crank will flex like a fishing rod and take out the #4 main. this is my theory on it anyways. there are many things to do to get around this. bigger aftermarket main caps, arp studs, halo girdles, and even a full girdle that in corporates the oil pan bolts to help hold the crank in are all options. some guys also rework the oil system restricting the oil to the camshaft and top of the engine so it will force more oil to the crank. to me that’s more like robbing peter to pay paul.

basically on the big engines, a safe rule of thumb is if you keep the lift of your cam less than .500″ at the camshaft and keep it under 4500 most of the time, you won’t have a problem. if you want to push it harder, you need to look hard into having everything rebalanced, oiling upgrades, and definitely pump some money into the bottom of the block to hold the crankshaft in.

As i said before, big block cylinder heads used letter designations. the better heads are cast with a “C,CA, or an E”. these supposedly have the best flow characteristics. however all of them were meant for leaded gas, and probably have small valves. which put you back in the same boat as before: go get aluminum heads. the only reason i can see to pump money into cast iron heads is if you want a stock appearance for restoration/collecting. 

the next common head were both the G casting and the Ga, which aren’t bad. the all too common head though on pretty much every 455 from 72-76 was the “J” head. most people call them smog heads. considered horseshit for performance a lot of people toss them out. what a lot of people don’t realize is they have more iron in em than most of the other big olds heads. so with some pocket porting  below 4500 the J head gets the job done nicely. if you want to goat an oldsmobile guy- grind the “J” off and say they are” I” heads!

as far as valvetrain- as you may have read previously in another blog, there were two different lifter bank angles. the 400/425 being 45deg and 455’s 39 degrees. olds engines to be honest have a non adjustable pedistal mount rocker arm set up. the geometry is pretty much horseshit so when you get into radical lift cams, you must switch over the entire valve train to adjustable rockers-cut heads for aftermarket springs and seals, custom length push rods, and then swear at it a lot. so hear again- hello aftermarket heads.

with the 350 engines, pretty much you are stuck with the same valvetrain issues. However the bottom end of the block was MUCH better with more material on the main webbing and a smaller crankshaft. also being a smaller engine you don’t need as much camshaft so the valvetrain nightmare may not be as bad.  the better heads for the 350 were the 5,6,and 7 designations. #8 heads being the most common and basically the small block equivalent of the J head. you’re still stuck with the same heavy block(as compared to a SBC) and oiling system though, so in that respect there are still some of the same issues as the 455. you just have less rotating weight and more block to work with.

well that’s all for today. thanx

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