Hi, I'm new to the forum. I have recently purchased my first Olds muscle car. A 1970 Cutlass S with a 350 auto trans. Unfortunately the engine froze and cracked at some point in the past. I have decided to replace the original engine with a 455. I own and operate a small engine performance shop where I have access to a complete engine machine shop including flow bench and chassis dyno. In the past I have built a few Oldsmobile performance engines but I have never built one for myself. I am very interested in learning as much as I can and applying it to my own custom 455 build. I look forward to build and testing some of the ideas and tricks that I have applied to other makes of engine in the past. I intend to share as much of that information with everyone and learning as much from you guys in the process. Thanks

 

Welcome! Pics of you new Olds would be spectacular! You've come to the right place, numerous folks here are way happy to help you with your questions, I know they've helped me alot.

Since you are planning on upgrading your car to a 455, you might also consider upgrading the trans to a TH400.

BTW, assuming your username reflects one of your rides, what year Z06?

 

Welcome to the site, post some pics of your cars.

 

Welcome to the group... Good luck with your engine project...

 

Im having loading pics. I will post them as soon as I figure out what I'm doing wrong.

 

Looks like I got lucky. Something worked.

 

I owned a 2002 Z06 before I got married.

 

To address the trans. I already rebuilt the TH350 with a performance kit before I found the crack in the 350 block. If i locate a TH400 before the engine is complete I will replace the TH350. If not I will use the TH350 until it fails.

 

Sounds like a fun project. The th350 should hold up fine and if it does break down then consider the swap would be my 2 cents. I am also a casual hobbyist so take my 2 cents for it's TRUE value, 0.

 

Welcome aboard

 

beautiful looking cutlass!

 

Thank You.

 

Sorry if it has been asked a million times but what happened to your 69 HO?

 

Nice 70.
Unless you really build that TH350 it's not going to handle anything a built 455 is going to throw at it. I'm sure you have all the knowledge and experience to build a really nice 455 that will be suited to your driving needs. If you do change to a TH400 you already know the differences for crossmember, throttle linkages, and driveshaft? Are you planning an upgrade to the gears too? Have you considered a 200 4R or an L460? They bolt in exactly the same as a TH400, only need the TV cable. It would give a great final drive ratio and rpm on highway if you decide to go grand touring.

BTW, those sport mirrors are a one year only production and worth their weight in gold.

I see Jim hasn't been back to address your question
It happened while he was driving it IIRC. Started as an electrical fire under the dash and went from there. Not enough fire extinguishers to put out the fire. Lots of interior damage and burnt paint on the outside. He sold the burnt out hulk and he says the guy who bought it restored it and sold it on BJ.

 

Sad story with a feel good ending!

 

Well I have purchased a standard 455 block, crank, rods, and bare C castings. I have already turned the crankshaft 10/10 on the split. I have filled the heat cross over int the heads. I am working on baseline flow numbers on the C heads vs a set of Ga castings that I have. I have a posted in the parts wanted section looking for an intake manifold. I am going to start on the block soon. I will be investigating the oiling problem that I have heard about. I will try to post pics as we go along.

 

I picked up Bill Trovato's book on Olds engines and was surprised to read that the so called oiling problems were a myth. With good machine work and blueprinting the engines showed no difference modded or not. Nice car, good luck.

 

So far what I have found is the rear main cap issue seem to be the most likely cause of Oldsmobile oiling issues. Also I scored an Edelbrock O4B intake manifold. I can not wait to get on the bench with this timeless jewel.

 

Welcome to the party! I'm a former Stingray 20-year owner but love these Oldsmobiles!

 

Can you be more specific about the rear main problem?

Is youre O4B a spreadbore version or squarebore? A well built Quadrajet will supply all your fuel needs, plus allows you to use factory throttle and trans downshift/throttle valve cables.
Remember your O4B is designed for off idle torque, so pick your cam accordingly

 

The rear main cap on the Oldsmobile engines has an oil drain back passage for the rear main seal. This passage sometimes interferes with the oil pump to main cap seal allowing oil pressure to return to the oil pan causing low oil pressure. It is my understand that Melling has redesigned the oil pump mounting flange to correct this, but it should still be checked. Because of the nature of performance engine building , once an engine is labeled with " poor oiling system" it is very hard to change that opinion. So it is my opinion that in the past the rear main cap issue caused oiling issues in the Oldsmobile engines forever branding them with having "bad oiling systems" leading to many necessary oiling modifications. From what I have found the oil drain back in the engine needs attention. Other than that, just the normal engine building techniques. Just my thought.

 

Would anyone be interested in a bolt on 1.7 rocker arm kit for Olds engines??

 

A few weeks ago I scored an unmolested 1974 Olds 455 at my local pick and pull. Here are some pictures of the "oil pressure Issue" that may have cause the 455 to be branded as an engine with a poor oiling system.

 

Olds Oil Pump

 

 

That probably doesn't help. Most of the failures I have seen on here and knowing guys who owned the 455, much less with the smaller main 350's, is improper machine work or too tight of clearance on the huge main bearings. Also factory soft rods, so so bottom end that can flex with the heavy parts flying around all lead to disaster. Olds didn't design the 455 to be a high RPM motor but guys have made it work with the right parts and machine work. Cutlassefi tested the OB4, he thought it was a terrible design and the Dyno numbers showed it. Nice car, enjoy.

 

O4B was terrible compared to what I wonder.