Toocool

The 330 "Ultra High Compression" engine in my 67 Vista Cruiser is tired, runs good but smokes and has a lot of blow-by. Will a later model Olds 350 bolt right in with all accessories bolting up? Are 330 heads the same as 350s? Will they bolt onto a 350 short block? I am looking for a little more power with a little less compression, not a hot rod but just a little bit more. Im basically a Chevy guy so I need a little help with my Oldsmobile.

joe_padavano

Yes, all SBO motors are externally identical. The heads interchange. There are detail differences in chamber volume and valve sizes over the years, but any head casting can be machined to take larger valves. This excludes the unique heads on the Olds 260, which have insanely tiny ports, and the 7A heads on the 1985-90 307 motors that also have small ports. Note that the 1977-up Olds small block motors use 1/2" head bolts whereas the 1964-76 motors use 7/16" head bolts. Also the 1977-up gasoline blocks have the less desirable windowed main webs. The one big difference that will potentially cause you a problem is that the 1964-67 motors use a different crank flange bolt pattern than do the 1968-90 motors. You need to use the flywheel/flexplate that matches your crank. Also, be sure to use the water pump, accessory brackets, and pulleys as a matched set. In this case, transfer everything from the 330 motor.

Toocool

Thanks Joe, I was hoping you would respond. So, If I buy a '70 350 engine I can just buy a flex-plate to fit the 350 engine and everything else will work? Sounds good to me. I'm thinking of buying a long block from one of the big rebuilders so the car isn't torn down for a long period of time. I'll keep the 330 just so I'll have it with the car in case a future owner may want it.

joe_padavano

Correct. I'd be surprised if any of these rebuilders have a correct solid main web early 350. I think most have the later windowed main motors. Be sure to check first - the block casting number for the solid main motor is 395558 2

olds 307 and 403

As said probably they will probably have the later block and heads. You may also get a 73 to 76 350 with the larger chamber #8 heads. Either scenario with the usual 24cc cast pistons, even at 0 deck, most end up .040" below deck, will result in 7 to 1 compression. Just a FYI, good luck.

Toocool

I actually want lower compression, but 7:1 may be a little too low. I just returned from a 3200 mile trip where 91 octane was the most I could find, some places 87 was all I could find. With the 10.25:1 compression it needs 93 octane or it rattles like crazy, I used at least 1-2 bottles of Boostane octane booster in every tank. This stuff really works. I would like around 9:1 compression if I could get it.

Sugar Bear

FWIW, If you're looking for better driveability and it's still a two speed transmission a lot can be gained by going to a TH350 or 200r4 while the engine is out. Nice to spend others $$$....

Good luck!!!

Toocool

Thanks but it has a Turbo 400, I am also going to change the rear gear from 3.08 to 3.36 to help a little on the hills. This last trip through Wyoming and South Dakota was almost too much for it. I have other trips like this planned for it in the future.

OLDSter Ralph

You are basing a change (lower compression ratio) on that "tired" engine. You have oil being inhaled into an engine that isn't giving you power. Oil fumes are a poor motor fuel. If you are using 1-2 bottles of octane booster per tank full, thats not good. I'm also betting the car could use a tune up. A "fresh" engine and heads would act very differently.

Toocool

I have been searching for a 350, calling the major rebuilders and no one has a 350 or a 330. One told me they would rebuild my 330 for $7875.00. Local machine shops are backed up for several months "if" they can find any parts for it. This is my traveling car, I have another long trip planned next year. If I dont have any luck pretty soon I'll have to drop a Chevy engine in it which I already have.

joe_padavano

I don't know anything about this vendor, but it's the first one that came up in a google search

https://www.mabbcomotors.com/catalog...ited-warranty/

Toocool

Joe, I called them, $1599 plus $470 for shipping from Texas to Tennessee. 2-3 months lead time to build it. Thats for a '68 350 long block. Sounds pretty good, but like you I dont know anything about them either. Thanks.
Edit.. Reviews are terrible.

Fun71

I saw these in the Classifieds section:

350 engine:
https://classicoldsmobile.com/forums...88-4dr-165770/

403 engine:
https://classicoldsmobile.com/forums...ans-am-165491/