I am going to rebuild a 73 455 block to put in my 1970 Cutlass.

The block is an Fa block, with a 4bbl carb and J heads.

The goal is a STOCK style, weekend driver, freeway cruiser. No racing, no going fast, not trying to win any races or get a low 1/4 mile

That being said, the J heads I have should be just fine. They have been decked. The valves need some light sealing work, turned I think is the word.

What is a good source or recommendation to get a replacement Cam and rebuild kit? I can find many many many performance cams. I want a cam that is just stock, or slightly better in milage and response. Ideas?

 

I'm absolutely no cam expert, but i have used an erson tq20 for a couple of years in my stock 455, and it is very mild and mannered.
214/214@.050 lift .478 lsa111.
Or simply play it safe and contact cutlassefi. He knows.
/ Anders

 

You say stock rebuild but the 73 455 engine had 8.5:1 compression ratio in stock form and a 70 455 had 10.25:1, so which "stock" configuration do you want? Personally, I would never deliberately build a low compression 8.5:1 engine when I could increase it to 9 or 9.5:1 to get better efficiency (both power and economy). The cost to rebuild is about the same either way.

 

+1. Why intentionally build a piggy smog motor when you can build a better motor for the same price?

- Eric

 

I should mention, I want to run 87 octane. Does that make a difference in what compression I want?

Other than port the J heads, what else do I need to do to a 73 engine to get it closer to a 70 engine, without sacrificing milage?

 

If your wanting to run the lower octane fuel then your original direction is the right one. With higher compression your going to need the higher octane. The .20 difference per gallon in fuel cost will save you $33/ year based on 15mpg and 2500 annual miles. I would opt for the higher performance.

 

Ewwwww. Why?


I should say so.


The most important difference between a '70 and a '73 455 was the compression ratio.
The same 400117 camshaft was even used on the non-high-performance 455s in both years.
The heads will matter when it comes to pedal to the metal all-out acceleration, but not with regard to normal driving around.

Are you sure you need to be able to burn 87?
Are you located in Mexico or on one of the Islands, where fuel quality is limited?

- Eric

 

I will be mostly in CA, or East coast. I have never really been the type of person to want to use high octane fuel. It just seems like a waste when I can go the same number of miles on the cheaper gas. I dont press hard on the pedal like hardly ever. If the difference is 250 hp vs 350 hp, 250 is still a lot compared to my 2015 Jetta TDI.

So I guess it sounds like I can build the bottom of the engine the same? THe 73 pistons the same as the 70? Use the same cam the 73 came with, and the stock rods and lifters and rockers? Then really the only "difference" was on the top end of engine with the heads and maybe the manifold? From what I am reading the J heads can be ported and made like the 70 heads with some work. I THINK that some of that work was already done by the last owner's machine shop. If the heads have been decked, which they have been, wont that increase the compression ratio a bit higher than the 73 stock number, putting me closer to the 70 numbers?

Also, if the bottom of, or "short block" is the same between 70 and 73, later, down the road when I am retired and rich, I can always put Edelbrock heads on and replace the J heads to get it to 70 specs?

Would the 73 pistons be the same as 70? Or would swapping those be in order to achieve what I am going for?

 

The 73-76 pistons were the worst of all BBO pistons. They were dished 40ccs. There is value in them pistons, however. If you press them off the rods, I will pay shipping for them as I turn them into nice ashtrays on the mill. That's about all they are good for.

Porting J heads seems like a lot of work to me, but they did leave a GENEROUS amount of material in the bowl area to make the shape you feel is right for flow/mileage.

It would seem to me you'd be miles ahead going with an earlier casting unless you really want to prove you can grind cast iron all day long for a week straight.

About the Edelbrock heads, why would you bolt a new, expensive set of heads on an old shortblock? When you decide to go Edelbrock, you need a shortblock to support it. That would mean going .030 over with new pistons (ones that can actually make compression).

 

But you can't.

In a high compression motor, which needs higher octane fuel, you will pick up a couple of MPG when using higher octane fuel.
In older engines, like ours, if you use lower octane gas, you will need to retard your timing, or you will have detonation (and in both cases, your fuel economy will suffer).
In newer engines with computer control and knock sensors, the engine will retard its own timing, and your fuel economy will suffer.



Sure. You're not going for any kind of a high-output build.



No. The 1973 motor should have 40cc pistons, which are a bit larger than the low-compression (9:1) '70 motor.
The high compression (10.25:1) '70 motor had 15cc pistons.



Yes.



The intake manifold in '73 had provisions for EGR.
The pistons have a deeper dish.



Sure, but as you explicitly say that you're not looking for a huge amount of power, why bother?



Yes, but by how much you do not know, until you cc the heads.



Kind of, but that would be a total waste of aluminum heads, as one of their chief advantages is the ability to run pump gas up to nearly 11:1 compression.

- Eric

 

The low compression pistons in 70 were 30ccs.

 

Ah. Thanks. I knew they weren't 40, and I knew they weren't 15, but I didn't know what they were .

- Eric

 

Ok to summarize...

Use the stock 73 cam
Use the stock 73 crank
Use 70 pistons
Use J heads, decked slightly, NOT ported, not worth time for what I am going for, and I can replace them later.
Use 73 rockers, rods, pushrods
Use 73 Manifold, retain EGR as it does not operate unless at WOT at freeway speeds (correct?) and helps to prevent detonation because of the hotter air at lower compression. Am I right? Or will I not need EGR at all?

this will enable me to use 87, 89 octane and be acceptable and improved performance with 93? Will it be marginal or below the threshold of not being able to use 87?

Are you saying that the edelbrock aluminum heads make the octane rating NOT an issue at all? I dont understand

 

This has nothing to do with the thread, but do you remember what the 69 455 hi compression pistons were (from a toro)? I was having a brainfade this past weekend?

 

I'd use any year 455 piston that had a smaller dish. But remember, if you are talking about using old junk, you need to know how to identify if the parts are still good or not.

The 455 cranks were all the same from 68-76 except for the material they are made of. With that being said, you will not make enough horsepower to hurt even the weakest ones.

I would really encourage you to buy an aluminum intake. You will thank me later.......unless you built a crane for easy removal and installation. What I am trying to say is that they are heavy. Very. Like it would be worth finding a used Performer for $100 type of heavy.

You can use the J's if you wish. I didn't mean to discourage you from porting them. I'm just saying, grinding cast iron is slow compared to aluminum, and the J heads had a LOT more material then all of the other prior heads. Porting heads doesn't mean you make the port bigger and you got a better head, porting is kind of like an artform, and requires you to think about shapes and geometry type stuff. It is fun, but take practice to do it right. What better head to start on then a J head.......and what better forum to learn the basics then this one:

https://classicoldsmobile.com/forums...echniques.html

You can use any year rockers from a 260-455, all the same except for the early BBO and SBO heads.



It's a matter of heat in the combustion chamber. More heat makes more pressure. More pressure makes more torque.......too much heat can cause the mixture being compressed to ignite before the spark plug fires the mixture. So you would have one flame front already traveling inside your cylinder which would meet the other flame front created by your spark plug igniting and when they collide, bad things happen.

Essentially, cylinder pressures spike beyond what an engine is capable of handling, and what usually happens is you ruin head gaskets, rod bearings and such.

Low octane fuel has a lower tolerance to pressure and heat as higher octane does. That's why when you run more compression, you use higher octane fuel because it can handle the higher dynamic compression.

Aluminum transfers heat faster than cast iron. If you have a perfectly tuned iron headed engine with 10:1 compression running on 93 octane, you would want to go up about a point higher in compression to retain the same heat in the combustion chamber as the iron head counterpart.

 

I would definitely try to get the better pistons…as stated before the difference in gas is minimal with just a few miles per year and will be gone if you really pick up just one mpg due to better efficiency with more compression…and do not forget that a car with more power may not be important for you but should you ever sell your car 99% of the buyers will prefer a more powerful car since nobody buys a 455 for mileage…so you will be able to sell quicker and at a higher price...

 

Ok, so sounds like I have the basics.

I will be using a crane to install the engine and transmission at once. So I am not too worried about the manifold being heavy.

About the ERG.... does that help solve the lower compression and prevent detonation problem?

I guess I need recommendations on what type of pistons to get now. The cynanders are original and not bored. So if I get it bored over ever so slightly and go with the smaller dish, what do you think??

I see a bunch of rebuild kits on EvilBay with new pistons and Rods and cams, though I would rather get the kit from a place like Jegs or Summit or Pace

 

EGR does nothing to improve running, and you will not be using it if you are completely rebuilding the engine.
They make block-off plates for the EGR flange.

- Eric

 

are you sure I wont be "using" it? If I use the j heads and the stock manifold with erg, wont it just be working anyhow? Will having it hurt? what will not using it at all gain me?

 

I don't know what changes there have been in Cali emissions or if an EGR would be required for inspection?

 

In order to run EGR, you have to have a carburetor with the proper tap for an EGR signal, and it has to be calibrated a bit lean to allow use of the EGR.
If you have all of the original parts, including little vacuum delay valves and such, and plan to use the original carb and original cam, with no real changes, then you can use it, but since it provides no improvement in performance, and leaves you with an additional bunch of parts to possibly break and make the car run badly, there really isn't any reason why you would want to use it.

I would just block it off like most people do and forget about it.

- Eric

 

Just some information for you, there was a post about this very recently. A factory iron intake manifold weighed 65 pounds and an aluminum Edelbrock manifold weighed 22 pounds.

 

I bench press 65 dumbbells, one in each hand, every couple days. I think I will be ok getting it on, even if I have to ask my uncle for help centering it on the gasket before dropping it down and torquing it on the heads. If I find a cheap edelbrock though maybe I will get it.

I read that the edelbrock manifold does not work under the ram air hood? Is that true?

 

It gets much more difficult to remove/replace when the engine is installed and you have to lean over the fender.

 

Ok, so I found a local guy selling a Holly Street Dominator intake.

Anyone know about that one? It sounds like a good one from my research. NO longer made.

I read that is also does not fit with the 442 hood, hmm....

It has EGR built into it, so I won't need to block of the EGR port, and if I feel like it I CAN block off the ports in the head with the Edelbrock block off plugs and cover the EGR on the intake?

I also see many Edelbrock Torker and Torker II. I think the main difference being the Torker has EGR and Torker II does not. Neither of those fit under the 442 hood either.

Any recommendations on a alum manifold that is good for just basic street performance, or stock style, and NOT $500 like the 1970 w30 manifold?

 

I have the Holley now. It has EGR.

I think I'll stick with the J heads, decked a bit.. I can get new heads down the road. 250 HP is the 73 rating, with headers and better manifold and decked heads and maybe improved cam and roller rockers I'm hoping that is around 300?

I'll go with 70 Pistons. What are the specs I need for those? Any vendor recommendations?

Any shops in SoCal that specialize in Olds or anyone know someone who is a honest engine machinist?

 

For a close to stock rebuild I would use Sealed Power p369 +.030. they have a 13cc dish and a comp distance of 1.725, that will give you around 9,3:1 with stock 80cc heads and a .042 gasket. Might even do 87 octane on that, absolutely no problems on 91. 252 dollars at Summit for a set of 8. Talk to Mark (cutlassefi) about a cam, and you don't need roller rockers on a build at that level. Unless your stock rockers are worn out I would put that money in good machinework instead.

Just my .02. /Anders

 

That sounds about what I want. I'll keep an eye out for head down road when I,m richer. I'll put more into machining the engine.

I think the j 73 heads are 79cc. Does that raise compression more?

 

Yes, but close to nothing. It's the same setup i had in my '72 455, and has worked very good for a couple of years. Right now I'm upgrading with 77cc edelbrock heads (9.85:1 with Smittys .011 gaskets), performer intake, hydraulic roller and rockers, and I'm keeping the pistons and stock rods for now, not going to race it, only show off with smoke from the rear wheels. You can always get a thicker gasket if you are afraid of higher cr.

 

Keep in mind when you go for roller rockers you need to measure pushrods for correct valvetrain geometry, sometimes bore and tap the heads for studs and in some cases mill the heads for guideplates. I know Mark have some good options on cams that allow you to use the stock valvetrain but will get you on the level of power you aim for.

 

Yah I think if I go all out on new heads I will go with the edelbrocks that have all that.

So I'll check in with Mark about a cam. Is that just a stock 70 one or something better? Id prefer it be a nice smooth idle and quiet in the passenger compartment. I think the only rumble I want it out the pipes in rear.

 

Just pm cutlassefi and tell him what you want. He'll take it from there.

 

Edelbrock Performer. Best bang for the buck on your combo.

 

that was easy.

So do I use the original pushrods and rockers? Or does the new cam need different length rods? When I put an edelbrock in my 80 cutlass I had to use shorter pushrods with my roller rockers

 

Got the manifold today. A little polish and she will look pretty

 

Updates

I sent the Heads out for rebuild. My Uncle's brother works on Heads out in Las Vegas. So he is going to do the valve job and deck them and make them nice.

I found a machine shop here in Ontario that comes highly recommended. So I am dropping it off there for the machine work. I may build the engine myself...? Going with the 1970 pistons but sticking with my J heads (for now)

I found this other intake locally and bought it. Would this be a better choice than the Holley i bought earlier?? I don't know much about it. I know is is for a Olds 455 and says 04B, but it is older than Performer. I think it won't clear an HEI distributor? Is that so? Or perhaps someone makes a slimmer HEI? Also, it does not have ERG, so would I put some Edelbrock head blockers in the heads? Are those removable later if I want? which intake would be better for milage and drivability with the edelbrock cam?

 

use the performer intake a totker intake is for raceing and high reving engines wont idle smooth

 

Based on everyone's input I decided on the following

1. Edelbrock 04B intake
2. SpeedPRO aluminum Heads
3. Comp Cams roller rockers
4. Edelbrock performer flat tappet cam
5. sealed Power 1970 stock size pistons
6. Imitation MSD distributer

I got a good deal on the parts and paid way under what the cost at Jegs, and Summit etc, through a local supplier/racing store. I went over my budget a little, but I am making it up by doing more of the body work myself then I had originally planned.

 

I would talk to cutlasefi about the cam. There are way better cams out there and he can set you up.
I am not sure what are SpeedPro Heads, but if they are Procomp make sure you get them bare and have your machinist set them up or buy them from Bernard Mondello.