Good afternoon,
I'm starting a 455 build for my 72 Cutlass and was looking for some feedback on a few camshafts I've landed on.
The Goal is for a nice, reliable street motor. I'd be very happy with mid 400s HP and mid 500s TQ.


455 Block bored .30 over
.010" / .010" Nodular Crank
Stock Oldsmobile rods, side beams have been polished, Mondello Notch
Sealed Power 369P Cast pistons
Edelbrock 61025 Heads
Edelbrock 2151 Intake

Machine shop is currently going through the block and crank but initially estimates the compression to be at 10.5:1 with .040" head gaskets.

I'm OK with a 2,200ish RPM stall and will probably run a 3.08 gear

Thank you for any insight!

Comp Cams Xtreme energy 224/240 Hydraulic Roller Cam

Herbert Cams C06PJ Hydraulic Roller Cam

 

Unless you cut the heads and/or block a bunch, you’re.nowhere near 10.5:1. If they didn’t cut anything, and they gave you that comp number, you need to find a new shop.
And with those heads you’d be better off with a cam with more lift. Just sayin.

 

Block is believed to be previously decked (not a bunch tho) but he has not measured it up yet, intends to provide updated numbers once he does that. The shop is very reputable and has been around for quite some time so hopefully he just got a bit ahead of himself.

Thinking more lift than the Herbert Cam as well?
I’m also trying to keep the lobe separation around that 110-112 mark but I’m ok going tighter if that makes sense.

 

Those pistons are .025” shorter than factory, the head gaskets are .023” thicker than factory, and (from what I’ve read) the factory piston-to-deck clearance was around .025” to begin with. So “not a bunch tho” might not be enough. The shop’s measurements will tell, but don’t be surprised.

 

[QUOTE=tooslow72;1651524]Good afternoon,
I'm starting a 455 build for my 72 Cutlass and was looking for some feedback on a few camshafts I've landed on.
The Goal is for a nice, reliable street motor. I'd be very happy with mid 400s HP and mid 500s TQ.

455 Block bored .30 over
.010" / .010" Nodular Crank
Stock Oldsmobile rods, side beams have been polished, Mondello Notch
Sealed Power 369P Cast pistons
Edelbrock 61025 Heads
Edelbrock 2151 Intake

Machine shop is currently going through the block and crank but initially estimates the compression to be at 10.5:1 with .040" head gaskets.

I'm OK with a 2,200ish RPM stall and will probably run a 3.08 gear

Thank you for any insight! [/QUOTE
Is this shop familiar with Olds engines ?
Are you going to shotpeen the connecting rods ?
Are you going to dyno the engine when its done ?
How many cc's in the piston dish ?
I personally wouldn't use cast pistons.
You better get "before and after" specs om head cc's, head thickness, deck height, piston dish cc's for just a few things. Find out how much is needed to be machined off to make the 10.5 to 1.

 

It sounds like a disaster already. You don't need a "Mondello notch", whatever that is. Cast pistons? Why?

 

Thanks for the insightful reply.
Comments like this will surely get the younger generation that's trying to learn involved in Oldsmobiles.

To answer your question, the cast pistons are new and came with the block I purchased.
It's what I have, if there's a good reason to go to a forged piston, I'm more than happy to receive useful advice.

I needed a set of rods for the block and found a very nice stock set from a fellow forum member. Maybe I don't need the 'Mondello Notch' but it's already there and I'm not building a race motor.

 

The “notch” does nothing more than maybe throw more oil on the cylinder set wall. Useless. And polishing the beams on stock rods is like putting a tuxedo on a pig. It’s still a pig.
And yes, you could buy a better piston, which would help your compression ratio issue. Most of the better aftermarket stuff, as described, is much taller, negating the necessity of decking the block.
I will tell you without hesitation, your shop is way off on the compression ratio number with your current piston. I’ll bet you lunch he just looked in the book, saw what it said, and obviously has not checked it. He’s not doing you any favors here, good shops don’t say anything until they’ve done the math.

 

Joe Mondello used to recommend putting a 1/2” wide, .020 deep notch on the sides of stock rods. It was supposed to help “oiling”. Like his restrictors, it did nothing.

 

Many millions of cast pistons have gone many millions of miles and plenty have done fairly demanding service, why the panic?!?

That parameter is set in stone, the question is about a cam.

tooslow - I suggest you directly contact Mark, aka cutlassefi, AFTER shop provides you with a complete set of measurements that affect cam choice. He has been very helpful to many in the Olds community.

Also be sure that the shop checks those rods. Nothing wrong with the notch but Mondello spent many years under deplorable management and have put out some really inept or defective work, they also put out plenty of good work. There’s only one way to find out - do not trust, but do verify.

​​​​​​….

 

Thank you for the reply.

To clarify I'm not set on having the higher compression number, to be honest, I'd prefer it be slightly lower, so I don't have to worry about fuel, spark knock, detonation, etc.
According to sealed power the CCs for the current pistons I have are 13.3CC. I ran the numbers through a calculator with a standard deck height last night and it showed 10.3 to 1 but the deck height is unknown at this moment and maybe I put the number in wrong, and I suppose there's really not any point in guessing until I have real numbers.
I know I need to get the CCs for myself. The shop has the pistons right now so I would need to go get one.
I agree that giving me a book number which is what he did, he said he looked in a book doesn't appear to be helping at this moment.

So, it sounds like I should move away from the stock rods and reconsider pistons.
I didn't think my desired HP and TQ numbers were all that high and thought that the set of rods and pistons I had would work well.

 

Sorry for hurting your feelings. Here's the straight scoop: the words "Oldsmobile" and "cheap" should never be in the same sentence if you're relying on anyone other than yourself. Don't worry about power if you're on a budget. Your cam profile is determined by your compression ratio, so get that nailed down first. Don't get hung up on numbers; they usually only work on paper.

 

You and your shop guy aren’t taking everything into account;
13.3cc dish
.045 in the hole, 10cc at least
Stock gasket 9cc at least
Heads 77cc
109cc total

944cc swept volume
+109 = 1053/109
9.66
And I assure you, this is a best case scenario, more than likely it’ll be around 9.5:1, maybe less.

You both are almost a full ratio off. Just saying.

 

You should start looking for a shop that knows Oldsmobile engines in case you feel the present shop is not capable. I don't much care how many Fords and Chevrolet engines they have done. Have a secondary shop found in case you need pull your parts out.

Olds rods with polished beams is a old drag racer's trick that hurts nothing. It can reduce the formation of a crack that could run across the beam and lead to failure.

Forged pistons are stronger and not likely to crack or break, causing a failure. .

 

They are also closer to or the same as factory pin height, so there isn't a built-in .025" piston-to-deck clearance that needs to be accounted for.

 

The problem is the massive decking needed as mentioned. It basically doesn't allow anything but cheap cast pistons in the block if zero decked. Leave them in the hole some what and the thinnest MLS head gaskets possible, if you are determined to use those pistons. I went with the much better Mahle forged pistons from Cutlassefi. My block needed a .016" cut, that left the pistons about .002" in the hole. If someone would have zero decked the block with cast replacement pistons, the better Mahle would not have been an option sticking . 020" out of the hole. Also the modern forged pistons run tight piston to wall clearance. My 4.100" 350 pistons are at .0025" piston to wall clearance.