BlueBlock350

Hi all,

I have a '77 gold colored Oldsmobile Cutlass Supreme Brougham and I am trying to restore it. I was was wondering if there was anything I can do to boost up the horsepower, or should I just try to find a 403? And if so, where are some good places to find them? A friend of mine suggested Advanced Auto Parts but what do you guys think? A crate motor can get expensive.

J-(Chicago)

If you think a stock crate motor is gonna get expensive, I fear you'r in for a rude awakening.
Wait till you have to buy the motor AND the machine work. A stock 403 is a great normal street motor and if you don't want to go too fast, it will do you righteous.
If you wanted to custom build either one to a specific horsepower range over say...300.
The 350 or the 403 will most likely be equally expensive, and probably over 4 grand.

If you are going to drop that kind of loot into your build, I'd personally recommend the 350 because the bottom end is stronger and it doesn't have as long of a stroke to slap around in the block. What's in it now?

J-(Chicago)

Man, I wish I had a 77. My fave Cutlass next to the 68

BlueBlock350

Its a 350R (i.e. the username "BLUEBLOCK350") brl carb it has 81k on the motor and 15 on the rebuilt trans. now does this mean that if I put a 403 in it that i will also have to change the tranny?

captjim

"If you are going to drop that kind of loot into your build, I'd personally recommend the 350 because the bottom end is stronger and it doesn't have as long of a stroke to slap around in the block."

I was under the impression that the 350 and 403 shared the same 3.385 stroke???

joe_padavano

You are correct. More to the point, a street driven engine (and frankly, all but the most extreme racing engines) will NEVER see the difference between a SMW and WMW Olds block.

78cutlass

I agree with joe - 403s make great stump pullin' daily drivers (gobs of torque). Add #5s, keep the CR conservative (9.5:1-10.1) and fry the back tires!

88 coupe

How strong does he need?


https://www.autoimagery.com/store/cg...12&sortfiles=2


NHRA record holder Tina Summerton, 78 Olds 98, weighs 4000 lbs.

11.21 @117 (7100 RPM) with 4a heads.

Norm

Oldsguy

I still get giddy when I see pictures like that. Two things: Awesome Oldsmobile torque, and excellent set up to get it to the rear wheels. Mmmmmmmm, Mmmmmmm good!

J-(Chicago)

That is a beautiful picture.

and...
Sorry for the misinformation. Somehow I remember my buddy's 403 rods being longer than my 350s, but I'm wrong often.

Sounds like he'd be happy with a stock build, but I dunno.

joe_padavano

The 403 rods ARE beefier than other gas SBO rods, but the length is the same.

BlueBlock350

Thanks guys. I think I will rebuild the one that I already have and clean it out a bit. The next question I have is I changed the oil last week and put in 5W-30 as told to by the guys at a local Advanced Auto Parts when i changed the oil with it it seemed to burn the oil. What do you think it could be? should I be putting in 10W-30 in a 350?

J-(Chicago)

In my opinion (which may or may not be worthless) If you're burning and leaking, I'd go thick on the oil. 20-50 or straight 30. Especially since the weather is getting nicer. Check your PCV system first, it's good to start with something simple.
You are not smoking BAD are you?

BlueBlock350

No. Not bad at all its just that when I changed the oil as soon as I got it, it was a little low, then when I drove it for about 20 miles or so I checked the oil level and it was low 2 quarts and the dipstick was smoking. So i added 2 more quarts and i was fine. Are you sure about the straight 30 oil that sounds pretty thick.

J-(Chicago)

I've been running SAE30 in my Delta for 5 years. 160,000 miles on it and it still doesn't burn a drop.

Also if your dipstick tube is smoking, your engine gases may not be properly ventilated. Make sure your Pcv system is in tip top shape. If you have 2 breathers instead of a Pcv and a breather, you are probably just sucking up air and blowing it out of the dipstick.

BlueBlock350

thanks for the advice. i will take a look at this weekend. I just dont have time during the week due to me not getting home til 8pm from work.

slumpy

heres my 77 i just got about 3 months ago, 403 sbo, 400 turbo, i love it already. has long tube headers and 2.5 duals all the way back.

Olds64

If you want to locate a 403 check late 70s Delta 88s, 98s and Toronados.