davepnola

Ok I put the 455 in and I am not to pleased in performance upgrade from the 350 , my brother says I am to used to my porsche turbo. I am an old mustang guy in the day and my 302 with 289 heads use to put it on some of the big blocks in the day .....

Here are the specs of the build : 1972 455 block 30 over with G heads stock freshly built. Hydraulic cam int 296 exh 311 valve lift : int 472 exh 496

Sae Dur . 289 int 300 Exh .050 Dur 214 int 224 Exhaust
Lob Ctr 106 int 118 Exh
Scorpion Roller rockers: 1.6 Remanufactured Rochester Carb 670 cfm from summit racing : stock cast intake : headers : stock distributor :
Stock air Cleaner :

Engine runs ok, but seems not to have the ***** I was expecting ?? Also I think I am getting floating of the points at 4000 rpms .... I bought and edelbroch 04b and will install this week .
please give me an opinion of the cam shaft and I know I need to upgrade the distributor to electronic, but I want the stock look .... thanks for your response....... PS: I am thinking of upgrading to a roller camshaft , but want opinions first.... Davepnola

olds425

The Pertronix units will fit in the stock distributor. I have one and it works well.

Insom

1. Carb is small.

Rickman48

That carb is a little small for those cubes, and probably jetted too lean.
Is the rear air door opening? Might have to adjust it!
I've found over the years, to set timing mostly by ear, as every motor is different.
Set it @10 degrees and snug it down, [not all the way] drive it, advancing it a little until it pings. Back it off 2 degrees, and tighten all the way! Done!
Just use the same octane/quality gas all the time!
Might be a little slow if you've 'highway' gears, too! How is it on the x-way??
You haven't said what body it's in, but Oldsmobies are all heavier than a porsche or muskrat!

442Harv

Did you degree the cam? Also is this a auto tran,and what rear gears? May need a higher stall convertor,if auto. Also with aftermarket cams, you need a lot of intial timing. I would start at least at 16 degrees, and go down if it pings to bad.Also I agree with other post, carb is probably to small, or at least needs bigger jets.,

J-(Chicago)

Compression ratio?
What is the timing curve?

davepnola

not sure of the gear , 350 trans shift kit , no stall , holley told me that this carb is the correct carb for application plugs look more rich than lean but not black rich more light brown not grey ..... how do i meaure the rear gear by spinning the wheels jacked up ?? also if I went to 1.7 rockers ratio how much more would that help lift on cam or am waisting my time , any opinions on the cam ?? no the cam was not degreed that I know of , Local machine shop built the motor , I wanted at least w30 specs he talked me out of it and thats where I am now ... thanks

Rickman48

You can jack it up from in front of the right rear wheel, [if it's NOT posi] in neutral, and count the revolutions of the driveshaft with ONE turn of the wheel!
Of course you'll have to approximate to the closest available ratio - but you'll be close!
Machine shop gave you what HE wanted, not what you wanted!
After you get a gear and converter, you might think about the rockers!
Cam is big enough to require maybe a 3:42 gear and a 2500 converter!
Then you'll need some sticky tires!

davepnola

posi traction rear end 10 bolt ....

citcapp

Carb is to small. Need at least a 750 or better. The cam should have been degreed. What type of pistons did the machine shop install. stock low compression, after market high compression. Need some more info

davepnola

he said dished low compression stock pistons , why is summit telling me this is correct carb .... i was told it is a 670 cfm any way to verify or rejett the carb or should i send it back ??

BIGJERR

Go with a Performer intake or a Torker,750DP Holley,Stock HEI was good to 11s for me........Cam needs degreed or you have no idea were your at.......Roller cam is a waste of time for this build IMO........

47 Convertible

Here is one formula and probably Summit is using one very similar to calculate their recommended CFM Carb. CARB CFM = Cubic Inches x Max RPM's / 3456 x VE% Where Cubic Inches = 455, Max RPM is probably 5000 to 5500?, the 3456 is a constant value and ve (volumetric efficiency) could be at 90-95% on a modified engine. You can make it 100% if you think that is possible. I've used this formula a bunch of times and generally find it gives too low a recommendation for all except stock engines.

Basically you got a kind of rebuilt stock engine except for the cam but I don't see where you gave the engine any ability to take advantage of the cam. There should have been at least an Edelbrock Performer on top and headers on the exhaust side so the cam can do its work. More rather than less compression would have been good.

You got what you got to work with. The best thing at this point is to take it to a good tuner with a dyno and see what is the most they can get out of it and then do what they recommend by way of ignition, intake and exhaust.

Caution: this advice is worth exactly what you paid for it. : )

davepnola

headers are on and 04b will be installed this weekened , what is the best advice on maintaining the stock look distributor but upgrade the insides to electronic and make sure that its curve is set to my engine specs ? Also I will call summit tom and get the next bigger carb 7802 i have the 7803 , i think the rep under estimated what I told him...

47 Convertible

Being a 72 you probably have the old style distributor. I just tossed mine (68) and bought a 74 or later HEI. But since you want to stay stock I would think about anything that eliminated the points would be an improvement. I believe there are a number of manufacturers that build those. Like a carb, it sometimes is money saved in the long run to have a distributor shop rebuild and set up your distributor specifically for your engine. I did with the HEI. It added $125 to the cost of things but well worth it in my old guy opinion.

cutlassefi

Need to verify the gear and compression ratio. I'd go with the Performer instead as well. Plus that cam is slow, but doesn't need 3.42 gears and a stall though, not in a big block. You have a few more things to check first.

Rickman48

O.K. - with Posi, jack-up both rear wheels and count driveshaft revolutions!
I woudn't use a double pumper on the street, with automatic and no stall!
I ran 12's in a 396 with a 780 vacuum secondary - 400 trans, 2500 converter and 3:55's

507OLDS

The Pertoniox kits are great for the stock points style distributors,to retain the stock look.There have been a few 455's dynoed lately,with the stock points,then the Pertronix kit,& the gains did show more power,and a steadier spark.
The O4B or Performer intake will be great for your application.Since you already own the O4B,and it looks closer to stock,keep that.
That 670 carb isn't exactly too small.It could possibly respond from better jetting.A 750 would be the most I would put on that.You don't need a huge carb since the Olds isn't a high-reving engine.With you compression ratio,and the other mentioned parts,I would change the cam.You have a little too much duration,and not enough lift.That cam is more like a Chevy grind.If you did keep that cam,you would need more compression,and a 1.7 rocker to make it work better.

cutlassefi

Do we know what the compression ratio really is?

citcapp

He stated that the engine builder installed low compression pistons. Most likely the late model stock deep dish piston. What a moron engine builder

cutlassefi

Gotcha, then yes it's the wrong cam, degreed? we don't know etc. He mentioned the spark plug color was light brown, not bad. So next would be to verify timing and/or gear and change cam. Jmo.

72 cutlass455

Don't use HEI with the 04B I have one and HEI will not fit. If you get a HEI use a newer intake.

f-85

X2 Why would he do that. Whats the compression? Around 7.5-7.8:1 And then use that cam???

Texas Jim

When I had decided to do work on my 455, I talked w/ afew guys on here about going to a machine shop that did "Oldsmobiles" specifically, atleast one that was familiar w/ Olds engines. My concern were the heads and and the block being machined correctly. Two guys said, "a good machine shop is a good machine shop, period." I always bolt all my own stuff up, and I would not have gone w/ anything but 10:1 compression or just alittle more anyway, but here this guy went to a place that installed the dished pistons when flat tops would have been the better choice. I still say, after building Chevys, Fords, and Chryslers f/ many years, although I'm only 53 years old, I have been building engines since I was in high school, and then only recently getting into Olds engines, but reading up in-depth on them, that when building an Olds engine, one needs to go to a machine shop that specializes in Olds machine work and knows those engines. In the long run, a person will be happier with what they end up w/ and not have to revamp a fresh engine. I'm in no way saying that you should tare into your new engine, davepnola, but an Olds engine is such a different breed than the old regular run of the mill Chevy, and I'm not knocking Chevys either, I've had great luck w/ them f/ many many years. One can't build engines other than Olds f/ even a long time and think that he knows anything indepth about an Olds. I'm so glad that I ended up wanting something different and chose the Olds (455), as Olds sure the hell is different from anything else. Best of luck w/ your 455, I'm sure that you'll find an external solution that'll do the job. Sincerely, Jimmy.

cutlassefi

I agree and disagree. Maybe the statement should have been "find a machinist with a head on their shoulders"

It's simple, rule of thumb on bearing clearences is .001 per inch of diameter. BBO rod journals are 2.5, hence minimum .0025 clearence. They live fine at that. Mains are 3.00 in. so you use a minimum of .003 main clearance, they'll live fine at that too unless it's real high hp.
Then look at the stock heads. you don't have to be a Rocket scientist (no pun intended) to realize they don't flow well or are very efficient. Therefore other compensations need to be made.

Low compressioned, mediocre flowing 70's stuff is all pretty similar. Some guys/shops just don't have the smarts or care enough about their work to stop and think for just a moment. The guy I take my stuff to in Jax is great but although he was not really an Olds guy he was smart enough to machine everything for proper clearances etc. Now that he's done 4 or 5 for me it's even easier.

Some machinists would rather sell everybody something just once instead of having repeat business from the same individuals. In this day and age that's probably not a good philosophy.

Texas Jim

I realize you know your stuff, from what I've gathered on this site. I'm only saying that w/ the ie; Olds 455 heads, it's much better that a machinist know about what the Olds heads need to run to the best of their ability, which from what I can gather, is alittle different from the other brands. I'd much rather have a machinist who's familiar w/ the BB Olds doing the work on my 455 Olds heads and block. The small details IMO are important and every little bit counts. Why go w/ a "good in general" job when it can be the best f/ the brand?

Run to Rund

The carb is OK with proper jets and metering rods, which it probably doesn't have. You have almost as much compression in the oil pan as in the heads It is hard enough to get over 9:1 with shallow dish pistons that are .025" below deck as they usually turn out unless the machinist decks the block enough.

Then, and possibly the worst, you have a lame camshaft to go with that lame compression ratio (actual is probably under 8:1). Add 20-30 degrees and some lift possibly.

Your engine was rebuilt for use in a farm tractor. Sorry, no insult intended. Still, it is OK for a 98 luxury sedan but not much else.

davepnola

just got off phone with machinist ,he said he had 2 options w30 spec pistons(high compression like 11.1) or low compression (factory specs for 1972) He said he chose that because that he thought with all that compression that the timing would have to be way back on pump gas on street . So I will jack car to verify the gear , he said he built the engine for low torque with that cam and with factory 14 wheels the car should roast the tires , but it bearly breaks em loose , I am bringing him the car to take a stab at it on the timing adjusting the carb tomorrow ..... we shall see ?? is this cam shaft like rv spec cam ?? Also I went with the 04b because I will be using the air induction setup and yes I just wanted the rumble with w30 package , thanks for the suggestions...... Davepnola In early days the small blocks I had had high lift cams with small duration for quick turn up ...maybe I am not use to the big block scenario.... OH I DID DO A COMPRESSION CHECK HOT ON THE MOTOR it was 150 pretty even on all cylinders ... if that helps any , and if he built me a tractor motor that will be non acceptable in my book , so any help to make the motor come alive would be appreciated....

Run to Rund

Well, some of the harm is non reversible, that is unless you get the high compression pistons. He probably left the deck pretty much alone too. Many machinists can't add and subtract let alone calculate compression. As I posted above, with the "W30" aka regular high compression pistons you won't really get very high compression unless you deck the block too.

Assuming you are stuck with those pistons and their bathtub dishes, get a thin head gasket, check head cc's and maybe mill them on main and intake surfaces equally so the intake will fit.

Get a decent cam, such as the Comp XE274H at a minimum (similar in size to the W31 and early W30 cam) or the XE284H (similar in size to the later W30 cam) and rear end gears in the 3.90 to 4.33 range. Many people don't recommend as big a cam with low compression, so I'd say you need a real 8 to 1 at the very minimum for the bigger XE cam.

cutlassefi

O.K. soooo let me get this right, you want him to get a bigger cam that will build less cylinder pressure and that will help? It'll be a real pig then.

Nothing could be further from the truth. Regarding camshafts when you have throttle response issues there are a few things you do first, advance it, get one with less overall duration, not more, at the very least less intake duration, again not more, and tighten the lobe seperation. The generic cams are not good, they're very seldom ground on the correct lobe sep for the application and their intake and exhaust lobes share the same profiles.

As far as pistons go, I think they only made 2 different ones, a 24cc and about an 18cc. But when you figure in the deck clearence and other factors even with the 18cc you only typically get less than 10.0:1. Don't be mislead by earlier printed info and advertisements, the stated comp ratio on the W30 stuff I think was around 10.25:1. But I'll bet you a days pay that if you tore a virgin one apart and measured it you'd be hard pressed to see 10.0, probably closer to 9.75.
And the old cams were slow but kept a half decent idle cuz they were ground on a wide 113 lobe sep.

I guess what I'm saying is you can help it with the right cam, tuning and maybe a gear, depending on what you have. A cam with 205-210 on the intake with a faster intake lobe than the exhaust and on a 110, maybe even a 108. That'll build cylinder pressure and help throttle response. Adding more lift via the cam and/or higher ratio rockers will help as well.

jmo.

davepnola

really not interested in milling ,that would surely change valve train , pushrods lengths, the motor does have the scorpion 1.6 non adjustable rockers , I suppose that would come in affect with milling etc.. as u say... I have used cometic metal head gaskets in our porsche turbo environment , I suppose they could do some thing .... before we start milling maybe I need to verify compression , I am sure he milled the heads and took something off of the block ?? does 150psi equate compression standard or how can I verify what compression is at ??

cutlassefi

Gotcha. If you had a cam with less duration and/or on a tighter lobe sep it would raise your cranking psi, it's that simple. I'm pretty sure you're around 8.5:1 based on that and the current cam specs.

davepnola

please recommend a better cam shaft to work with current pushrods and roller rockers ? I would not be opposed to a roller cam , but is it worth it my situation ??thanks

Run to Rund

Different opinions, different approaches. I built a relatively low compression (9:1) 400 with a very big Comp XE cam and it ran mid 12s in the quarter on pump gas. Sure you can get more cranking psi with a "nothing" cam, but it still won't perform at any rpm. For instance, Sam Murray's 72 Cutlass 350 J/S is a low compression "pig" but he sure didn't put a little cam in it. It holds the NHRA record at 11.37 sec.

cutlassefi

What gear/stall and how much do the cars weigh?

davepnola

so would the 1.7 rockers increase the cam by what or, should this cam be totally scrapped , if i go into the engine , i want it to be one time and be done to enjoy.... i am really being displeased in what was recommended on this build .....thanks for your response...

72 cutlass455

My 72 is hard not to burn rubber with haha. The big thing with big blocks is torque horse power is nice too. I agree the proper stall torque converter and better gears in the rear. Also think about getting a 400 tranny the extra torque may not be kind to the 350 tranny. That engine should rock did they hook the vacuum modulator on the transmission back up ? Had some fakanics work on my 455 and they didn't plumb it back in was stuck in first gear had to shift manually.

507OLDS

There are a lot more piston options than just 2.If he did narrow his search to the typical TRW/Speed-Pro style,then yes,there are 2 compression options,but the higher-comp option is nowhere near 11:1.At average,the smaller-dish,higher compression style pistons are around 9:7:1 with a stock head,uncut deck,and Fel-Pro head gasket.The lower compression poistons are 8:5:1,and I am guessing that is what you have.
That cam is not a low-end,high anything.It's a dud for that application.I'm not sure what guide he was looking at.I'm guessing he was browsing an internet wholesaler.The answers are not in there.

On another note,we just dynoed a bone-stock restoration 70 W30 engine,with stock cast pistons,stock W30 intake,F-heads,W/Z manifolds,stock stamped rockers,etc,NO porting,no changes,and it made 350HP,480ft-lbs,so it's right there with the factory advertised specs from 1970.This will run on pee-pee gas.

geckonz08

Have heard that before .Also heard one can just grind a little off the o4b and it works fine ?
From your observation ,do you think grinding would be possible and suit fitment??

72 cutlass455

Geck it may be possible but the 04b is a old intake and i would think the newer ones that fit would flow better.