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Hey guys, I'm currently restoring my olds which has a 1974 455 engine with 8.5:1 compression. How much can I bump up the compression numbers by replacing the stock dish pistons (40cc i guess)
with aftermarket pistons on a stock engine block? I found these Forged pistons by DSS Racing are they correct for a stock block and what do you recommend, i'm open for opinions as this is the first engine I build. Andrew
Dump the J cylinder heads. Get an earlier set and don't go much past 10:1 for good pump gas. Decent hydralic flat cam or roller if your budget allows. Should make close to 400 hp if done right.
What parts do you reccomend, I have budget of 6 grand, I'm interested in the edelbrock top end kit since its an already made setup so it would just bolt on. They claim it makes 450hp on a 9.5:1 engine so not sure how it would perform in my engine.
Dump the J cylinder heads. Get an earlier set and don't go much past 10:1 for good pump gas. Decent hydralic flat cam or roller if your budget allows. Should make close to 400 hp if done right.
You’ll get about a 1.65 point increase in comp ratio to 10:1 with those pistons…the actual measured comp on the late 455’s is approx 8.35
thats with an 82cc head and the stock type fel pro head gasket.
Thanks now I have a clearer idea, is it healthy to run this compression or should I is it better to go for slightly lower numbers? Lets say I will add headers, port match and polish the heads and intake manifold, would this have any effect on the compression and have it to high to use with regular fuel?
Andrew, doing those things will improve the engines breathing ability but not change the compression ratio and no it would not negatively effect the use of regular fuel (still using pump gas per post 2)
Thanks now I have a clearer idea, is it healthy to run this compression or should I is it better to go for slightly lower numbers? Let’ say I will add headers, port match and polish the heads and intake manifold, would this have any effect on the compression and have it to high to use with regular fuel?
There is nothing wrong with running 10:1 , you just can’t go to small/mild on your cam choice..
once you know what heads , gears , converter and a few other things, we can give you a ballpark on the cam choice.
what kind of power do you hope to make and what vehicle is it going in?
There is nothing wrong with running 10:1 , you just can’t go to small/mild on your cam choice.
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Yes you can. You of all people should know there are lots of stock or nearly stock 10.0:1 builds running around with mild cams, and they run just fine.
'
Yes you can. You of all people should know there are lots of stock or nearly stock 10.0:1 builds running around with mild cams, and they run just fine.
Here we go. The resident expert here to make himself look like a fool again.
why do you keep doing this to yourself? 😂
I could pick a little TQ type cam thats designed for building cylinder pressure in low comp engines,,,,it would rattle itself to death in no time at 10:1 and probably have 200+ crank psi. also notice I never gave any exact cam specs… yet you said yes?, yes to what numbers?
we don’t know the car or gears or what the guy prefers or what fuel he would be using, or the rest of the engine combo
You really need to stop shitting in peoples threads. Provide information that is helpful for the topic at hand and just leave the other stuff out of it.
Here we go. The resident expert here to make himself look like a fool again.
why do you keep doing this to yourself? 😂
I could pick a little TQ type cam thats designed for building cylinder pressure in low comp engines,,,,it would rattle itself to death in no time at 10:1 and probably have 200+ crank psi. also notice I never gave any exact cam specs… yet you said yes?, yes to what numbers?
we don’t know the car or gears or what the guy prefers or what fuel he would be using, or the rest of the engine combo
So all those ‘68-‘70 442’s (non W30’s) out there, that have pretty mild cams in them from the factory, are rattling themselves to death, gotcha.
There is nothing wrong with running 10:1 , you just can’t go to small/mild on your cam choice..
once you know what heads , gears , converter and a few other things, we can give you a ballpark on the cam choice.
what kind of power do you hope to make and what vehicle is it going in?
It' the original engine of the 1974 442 (4bbl, dual exhaust, posi rear end, th400) i'm restoring, you can check the progress on my profile. The car will be a cruiser, in not looking to race it but I would like to get more power from the engine close to older model 455s. Is an edelbrock top end kit with ARH headers, 3.23 gears and 2,500 stall converter a good setup on a stock engine block and pistons?
If you are open to other piston options, check these out at Summit:
Speed-Pro Forged Pistons L2323F30
I built a similar 455 to what you are doing if you want to check out my build under Major Projects that has all the specs. This was my first engine build and wish I could do it again, was a lot of fun and learning. Especially the help on this site. Good luck!
Andrew keep in mind the 71&72 W30 are 8.5:1 compression engines.
Gross specs are 350 hp 460 lb ft.
Edelbrock #2152 cam generates 445 lb ft. With Performer intake and stock cylinder heads.
I noticed this and it got me confused how do they make significantly more power than later engines? Is it due to smog equipment, worse flowing heads or something else?
Last edited by Andrew Anatian; Jul 26, 2024 at 09:57 AM.
I noticed this and it got me confused how do they make significantly more power than later engines? Is it due to smog equipment, worse flowing heads or something else?
A combination of those things plus more severe tuning for lower emissions along with the introduction of catalytic converters in '75, which was pretty much the last nail in the coffin for performance in the '70s.
A combination of those things plus more severe tuning for lower emissions along with the introduction of catalytic converters in '75, which was pretty much the last nail in the coffin for performance in the '70s.
I noticed this and it got me confused how do they make significantly more power than later engines? Is it due to smog equipment, worse flowing heads or something else?
All the above, the 66-72 W30 is Oldsmobiles masterwork for performance while maintaining everyday practicality. The culmination of 70 years of engine building know how for the masses. Then they had the rug pulled out from under them by 1973.
Bottom line, you can make muscle era power via 8.5:1 . 1972 W30s have 30% more hp and are 2 seconds and 10 mph faster than a top of the line 1974 442. And if Edelbrocks power package can get it done without the headache of trying to emulate a W30, go for it. However if the package doesn't blow past W30 numbers, you will need to maximize the drive train as Oldsmobile did to see similar performance.
Something else to consider is the weight penalty on a 74. You have 500 lbs on top of a 72 W30. So your 455 needs to generate 50 more hp to fully be able to run with one.
You really need to stop shitting in peoples threads. Provide information that is helpful for the topic at hand and just leave the other stuff out of it.
I noticed this and it got me confused how do they make significantly more power than later engines? Is it due to smog equipment, worse flowing heads or something else?
throw those numbers in the garbage as they aren’t comparable to each other when they are under different rating specs
It' the original engine of the 1974 442 (4bbl, dual exhaust, posi rear end, th400) i'm restoring, you can check the progress on my profile. The car will be a cruiser, in not looking to race it but I would like to get more power from the engine close to older model 455s. Is an edelbrock top end kit with ARH headers, 3.23 gears and 2,500 stall converter a good setup on a stock engine block and pistons?
that’s a good all around gear and converter choice.
yes on the headers ..don’t go bigger than 1 3/4” primaries.
Edelbrock Performer-Plus Camshaft #2152. Camshaft specifications: - Intake duration: 214 Degrees - Exhaust duration: 224 Degrees - Intake lift: .472" - Exhaust lift: .496" - Lobe separation: 112 Degree - Intake Center Line: 107 Degree - Vacuum: 15". You think i can run this with low conustion?
stay away from the Edelbrock cams. they are old style lobes. There are much better choices out there that will make more power over a wider range , make more vacuum at idle for power brakes too
Last edited by CANADIANOLDS; Jul 26, 2024 at 03:27 PM.
All the above, the 66-72 W30 is Oldsmobiles masterwork for performance while maintaining everyday practicality. The culmination of 70 years of engine building know how for the masses. Then they had the rug pulled out from under them by 1973.
Bottom line, you can make muscle era power via 8.5:1 . 1972 W30s have 30% more hp and are 2 seconds and 10 mph faster than a top of the line 1974 442. And if Edelbrocks power package can get it done without the headache of trying to emulate a W30, go for it. However if the package doesn't blow past W30 numbers, you will need to maximize the drive train as Oldsmobile did to see similar performance.
stay away from the Edelbrock cams. they are old style lobes. There are much better choices out there that will make more power over a wider range , make more vacuum at idle for power brakes too
I've havent seen any good feedbacks for edelbrock cams and can't find an olds that has them lol, maybe comp cams XE 224/230 # 42-223-4
Last edited by Andrew Anatian; Jul 26, 2024 at 04:49 PM.
I have a CC XE262H (218/224 @ 0.050, .462/.469, 110° LSA) in my 400G and TBH, it's just a little bit more than I wanted but I'm used to it now. Might be perfect for your application. I'm thinking you need a minimum of about 9.5:1 CR to keep it happy.
I may be biased, but that cam’s specs always seemed off to me. The lift seems way too short for the 218 duration. Most 204 duration cams have around that much lift. My 217 cam has .485” lift.
I may be biased, but that cam’s specs always seemed off to me. The lift seems way too short for the 218 duration. Most 204 duration cams have around that much lift. My 217 cam has .485” lift.
Kind of agree. In retrospect, I think I would have been happier with a skooch more lift and a skooch less duration.
The multiplication of a rear gear ratio and 1st gear ratio of around 10.0 is ideal for performance. In the case of 1974 442 vs H/O, everything was the same except the fact that the H/O came with a better rear gear standard. At the same time now that the H/O was quicker, 0-60 in 7.8 vs 8.3 seconds. It helped justify the W30 moniker that only H/O carried. And H/O only offered a even better gear as an option. Vs 442 also offering better up to a 3.42 which is great, but several worse. Insuring that any time the 2 models lined up the H/O would almost always be more impressive.
0-30 on the 442 is 3.1 to the H/Os 2.7 seconds, the torque of the 455 makes up for lack of HP here. As 3 seconds to 30 is muscle era performance but then the lack of HP kills it on the end and these models drop 2 seconds off of their predecessors standards. H/Os 16.0 in the 1/4 and the 442s 16.2 is because they weigh too much for the power they produce to be quick. The weight gain alone (+500 LBS) kills 40-50 HP that's already missing due to malaise era standards. 1974 455s are so neutered that regular factory high compression 350s make more power. 230 net to 250 net.
With regards to engine specs, flywheel dyno stats are always gross unless otherwise specified. The factory gave you up to 400 HP gross maximum, professional engine builders today can give you 500 HP. Sure they can do more but ease of use, drivability, etc, will be compromised.
P.S. As far as the bickering that's going on within this thread, think "too many cooks in the kitchen". CANADIANOLDS, cutlassefi, VORTECPRO, etc, all know what they are talking about, but have their own recipes, their own cooking methods, so to speak. Bumping heads is inevitable. Real life scenario, Phil Jackson legendary basketball coach will go down in history as the greatest coach that ever lived. Because he managed to get 5 hall of fame players that all thought they knew better, to work with each other and win 11 championships. In Classicolds case, there is no coach. But having all the players/cooks is a great thing. You just have to take what you can from each one of them and go from there.
And H/O only offered a even better gear as an option. Vs 442 also offering better up to a 3.42 which is great, but several worse. Insuring that any time the 2 models lined up the H/O would almost always be more impressive.
”As an option” is key. In the 80s my neighbor had a 1975 H/O with a 2.56 rearend.
The multiplication of a rear gear ratio and 1st gear ratio of around 10.0 is ideal for performance. In the case of 1974 442 vs H/O, everything was the same except the fact that the H/O came with a better rear gear standard. At the same time now that the H/O was quicker, 0-60 in 7.8 vs 8.3 seconds. It helped justify the W30 moniker that only H/O carried. And H/O only offered a even better gear as an option. Vs 442 also offering better up to a 3.42 which is great, but several worse. Insuring that any time the 2 models lined up the H/O would almost always be more impressive.
0-30 on the 442 is 3.1 to the H/Os 2.7 seconds, the torque of the 455 makes up for lack of HP here. As 3 seconds to 30 is muscle era performance but then the lack of HP kills it on the end and these models drop 2 seconds off of their predecessors standards. H/Os 16.0 in the 1/4 and the 442s 16.2 is because they weigh too much for the power they produce to be quick. The weight gain alone (+500 LBS) kills 40-50 HP that's already missing due to malaise era standards. 1974 455s are so neutered that regular factory high compression 350s make more power. 230 net to 250 net.
With regards to engine specs, flywheel dyno stats are always gross unless otherwise specified. The factory gave you up to 400 HP gross maximum, professional engine builders today can give you 500 HP. Sure they can do more but ease of use, drivability, etc, will be compromised.
P.S. As far as the bickering that's going on within this thread, think "too many cooks in the kitchen". CANADIANOLDS, cutlassefi, VORTECPRO, etc, all know what they are talking about, but have their own recipes, their own cooking methods, so to speak. Bumping heads is inevitable. Real life scenario, Phil Jackson legendary basketball coach will go down in history as the greatest coach that ever lived. Because he managed to get 5 hall of fame players that all thought they knew better, to work with each other and win 11 championships. In Classicolds case, there is no coach. But having all the players/cooks is a great thing. You just have to take what you can from each one of them and go from there.
Man understanding these cars has been a process so far and I appreciate everyone’s help. I had saved up some money and thought of dropping it on a power package, pistons and a few other parts all at once. I’m gonna steer away from that direction as I noticed its not the right way to go, especially that I haven’t drove the car yet. I’ll go part by part and see which setup best fits my needs.
”As an option” is key. In the 80s my neighbor had a 1975 H/O with a 2.56 rearend.
Yes, terrible wasnt it. As far as I can tell the 75 H/O was one of the most option laden Oldsmobiles in history upon its release, whether by availability or out the door. Yet could only be had with a 2.56 rear. Nothing crazy just a moderate move to a 3.08 would of been a world of difference. And still a silky smooth ride.
Originally Posted by Andrew Anatian
Man understanding these cars has been a process so far and I appreciate everyone’s help. I had saved up some money and thought of dropping it on a power package, pistons and a few other parts all at once. I’m gonna steer away from that direction as I noticed its not the right way to go, especially that I haven’t drove the car yet. I’ll go part by part and see which setup best fits my needs.
Sorry Andrew did not mean to discourage you. Information overload, I am an Olds guy since the mid 80s and a numbers addict, didn't mean to do that. Throw in a few 100 passes at the track over the years and I can get carried away ...
But getting familiar with what you already have and proceeding slowly is a good way to go. Your ride came with 370 lb ft of torque that is a lot of fun on the street as is.
Nothing crazy just a moderate move to a 3.08 would of been a world of difference. And still a silky smooth ride.
Yep, in the 80s I did that with my 1970 Supreme. Changed from a 2.56 rear to a 3.08 and the car was so much quicker but still nice to drive. Then changed to a 3.55 and that made a HUGE increase in performance. Interestingly, the city mileage stayed the same as it was with the 2.56 gears.
