Olds 350

[BlackTA]

I have recently purchased a 79 trans am with an oldmobile 350. Apparently a previous owner disliked the 400 the car had stock so installed a motor he trusted more the Olds 350. What can you guys tell me about this motor.
I am looking for a HP estimate this is all I know about the engine...
Oldmobile 350
Holley 650 4-bbl carb
.650 cam lift
hooker headers
Dual Glasspacks
otherwise I believe it to be stock
any guesses on HP and torque?
What is the Redline of this motor?
What octane gas would you suggest I run Ive been trying to put premium in or at least 89 octane but with 10 mpg and driving 300+ miles a week that gets expensive fast. If the engine needs higher octane I dont mind shelling out my cash but if I am wasting my money and it will run the same of 87 then I will start putting that in.

[BlackTA]

I have recently purchased a 79 trans am with an oldmobile 350. Apparently a previous owner disliked the 400 the car had stock so installed a motor he trusted more the Olds 350. What can you guys tell me about this motor.
I am looking for a HP estimate this is all I know about the engine...
Oldmobile 350
Holley 650 4-bbl carb
.650 cam lift
hooker headers
Dual Glasspacks
otherwise I believe it to be stock
any guesses on HP and torque?
What is the Redline of this motor?
What octane gas would you suggest I run Ive been trying to put premium in or at least 89 octane but with 10 mpg and driving 300+ miles a week that gets expensive fast. If the engine needs higher octane I dont mind shelling out my cash but if I am wasting my money and it will run the same of 87 then I will start putting that in.

[Bill Morgan]

What is the head code?

It will be an inch-tall number cast in the left end of the head. I speak some Oldsmobile, since I have a '68 442 with a 410 HP 462 Olds engine.

Also, do you have the stock iron intake? If so, is it EGR or non-EGR?

[henry203]

We would need to know what kind of pistons and heads you are using. The type of fuel depends on compression.

[BlackTA]

Bill I will look up those codes for you tommorow and check out the intake.

Mac, I have no idea what kind of heads and pistons I would assume they are stock.

Anyone know what kind of hp this engine produced stock?

Also could someone shed some light on what exactly a .650 cam lift means?

[henry203]

.650 is the lobe size on the cam, if you have the cam card it tells you everything. .650 is pretty big. The large the lobes the more performance you gain, but the more gas/wear you use. Id assume that if they put in a .650 cam that the rest of the engine is not stock

stock Hp depends alot on the year it was made, earlier engines had ALOT more horsepower than the newer engines. Mostly becase of emissions and the gas crisis.

[BlackTA]

What is a cam card? All I know about the engine is what I was told by the guy I bought the car from whom I might add knew nothing about cars. He simply said that it had a .650 cam lift, a 650 holley carb and hooker headers. I have a 3.73 rear end some people have told me a larger cam is often installed with a rear end with a higher ratio numerically. I was thinking of switching to a closer to stock rear end would this be unwise if in fact I do have such a hot cam? Is there somewhere I could look for an engine code to see what year the engine is?

[Bill Morgan]

Go to http://www.442.com and click on the FAQ link for a world of Olds facts about engines, heads, rear gearsets, etc., with which you can do first-hand research on your block, heads, etc.

[henry203]

mmm its late lol, I should be asleep.

Anyways, the casting #'s would be at the rear of the block on the drivers side. run those and see what year block it is. You have to also chec the heads, they may not be original. Either increasing or decreasing the HP. You may also have different valves. Problem with this sort of engine is that you dont know what people have swapped and done to it in the past.

the cam, rear end, holley are problably the three bigger factors in your poor gas mileage. You can take off parts of the front end to pull the cam with the engine still in the car. A rear end swap isnt that hard either. The holley you can change to a rochester in about an hour.

[jpratt]

Have you found anything to ID the heads or anything else about the engine. I don't know much about Olds, but 0.650 lift sounds very fishy unless it's a bracket car; it sounds like it was a driver, though. I have worked on a friend's 79 TA with the Olds 403 and it ran well with Performer cam and intake w/ rebuilt Q-jet and got reasonable gas mileage (w/3.73's although the original 2.73's were better)

HP, torque, redline detonation resistance all depend on factors like real compression, cam specs, etc. How does the car run in general? Is it well tuned?

[Mr. P-Body]

If I were to guess, I would say the cam is probably NOT .650" lift. If it were, the rocker assemblies would be the expensive "shaft" type, and the thing would not really "idle", but more like a "fidget". I would also bet the guy had no clue, and engine is actually a 403. They look alike, and use a lot of the same externals.
It is commonly asssumed by those outside the hobby (or business) that all Pontiacs had 400s. The 403 was the more plentiful engine in the '77-'79 era for T/As. If the scoop says "6.6 Litre", it was an Olds, stock. If it says "T/A 6.6", it was a 400.
Just some food for thought...

[henry203]

If you have a 403 than the heads will more than likly be 4A or 4B, its in large lettering on the drivers side, at the front of the block.

Hopefully you do not have a 403, otherwise the guy totally lied to you. Although I think if it was a 403 it would be eating alot more than 10mpg with the other mods you have

[BlackTA]

ok here is the deal... I dont think the guy lied to me so much as he was a complete moron. The work was done to the car by the guy that owned it before him. Supposedly this owner removed the 403 which was in it stock because he felt the 350 was a much more reliable engine.
I just looked for numbers at the front of the block just behind the pulleys I have the number 557 265 4B

The heads are 4A and read 554 717 around the middle of the valve covers

The intake is reads Edelbrock across the back and says "Performance 350 Olds" in the front

As for my idle its a little rough and I idle what I would condsider high...It idles at 1000 in nuetral and 750 in gear. I do not think the engine is in very good tune. I dont know exactly what I am getting for milage since my odometer reads off due to the rear end. I am just assuming 10 mpg because I use roughly a quarter tank of gas to get to and from work which is 50 miles round trip. And thats when im driving like a grandma. I can use alot more gas when ive got my foot on it

[Bill Morgan]

You have a 403 Olds engine, which uses the same intake as a 350, since both are Olds small blocks.

Were I you, I would start toward procuring a 400 Pontiac and all the components necessary to install it.

[BlackTA]

Thanks Bill but I dont have that kind of money. Whats so bad about the 403?

[henry203]

Usually 4b blocks came with 4b heads, and 4a with 4a etc. So somewhere down the line someone swapped heads I think. At least all of the original blocks ive seen have had this combo. 403 is a great engine. The only downside to it are the windowed main webs. It doesnt pose a problem unless your building a race motor that will run 6K rpm. alot of "experienced" oldsmobile haters will tell you that they crack and split...NOT TRUE. The other problem with the olds 403 is the very low compression and smogged heads. Install some # 4 #5 #6 #7 #8 heads with big block vaves, raise the compression from 7.9:1 to 9.5:1 and you will see a raped ape for a motor. stock is 185hp, 400hp isnt out of the question.

Your idle and gear rpm is exactly STOCK specs. The olds engine could be rough at idle for a number of reasons. Bad gas, tune up needed,cold weather, clogged fuel filter.

Building the olds engine in your case is probably a better idea since your on a budget. You can buy a rebuilt kit from seal power with new pistons cam, everything else for $500. If you dont have to machine anything you could have it totally rebuilt with freshened heads for about $800 if you do alot of the work yourself.

Sorry to say but you were majorly ripped off. Try and get ahold of the guy and see if he will give you a partial refund. You should have checked the casting # on the block and heads. Since your engine isnt upgraded than just switch the rear back to the stock one. If you have your build sheet you can check. that will really boost your mpg. a 2.41 will probably add 3-4mpg highway but thats about it.

[BlackTA]

thanks for the info. Maciej- Which engines would I find these heads on, and what would you expect me to pay for them. Will my intake and other parts still work with the different heads? Say with the mods ive got currently I am producing somewhere around the 250hp area, what would I produce with the same setup but a set of either aftermarket or different heads?

[henry203]

I doubt the owner installed any of what he told you. If he didnt even know the difference between a 350 and a 403. .610 lift is also VERY LARGE. The heads you can get off any earlier 350 oldsmobile. You need to enlarge the bolt holes but thats not too hard. If you buy some already finished heads(cheapest route) expecet to pay about $300. You just have to make sure they have enlarged bolt holes for the 403. Same intake, not a problem. I would recommend getting an edelbrock performer, same as factory but lighter and better flowing. You can also get a Cam matched to that intake.

[Bill Morgan]

I've got the Edelbrock and a set of #7 heads down here in Texas if'n ya can't find anything closer.

[olds]

I got my head cores #4 from Chris Witt. They will be cores...nothing more
[email protected]
517-449-0432
Lansing MI 48911 [Home of Olds]

Like was mentioned before the heads you want are #4, #5, #6, #7 or #7a The #4s and #5s will not be all the easy to find. Personally, I think #4's are the best. Drill the head bolt holes in the heads to 17/32 and still your 403 valves in them. That is it....

As for a cam...no more than .500 lift is really needed. If you are on a budget run a 214/224 duration. PAW sells that cam and it is as good as any. If you want to get more radical, then something around the 224-230 range.

If you car smells of raw gas when idling...the cam is too big. Been there before. My new setup is a lot better.

As for the olds motors....The popular hot rodding EMC is over and OLDS had a killer time. Several motors over 600HP. Dick Miller made over 600HP in a 403 on pump gas. BTR made 627 HP in a 350 olds on pump gas. I do not think any Pontiac motor placed in the top 10. There are more aftermarket parts out for olds now. Dyno's do not lie. This was a Jeg's sponsored event this week. It will be in the magazine soon. Nuff said.
http://www.realoldspower.com/phpBB2/viewtopic.php?t=14266&postdays=0&postorder=asc&start=135

Good luck
olds

[Mr. P-Body]

The block problem with 403 is very real. Over 6,000 RPM, the block flexes too much. This won't necessarily result in a broken block, but it WILL result in a broken crankshaft, usually right behind the front main journal.
We did one back in '79, when the cam went flat (a lot of them did) in my friend's '77 T/A. After a good valve job, a "performance" cam (TRW was the only thing out there at the time, for reasonable money), a Holley Street Dominator (also the only thing at the time), an HO Racing "accuracy kit" in the distributor, and an SD Q-Jet, the thing would fly! Stock, it labored to get 5,000. Once modified, it would throw the belts at 6,800.
Definite power potential. Definitely a weaker engine than the Pontiac, in durability.
There is a rumor that the earliest versions, used in station wagons, had full-bulkheads in the main webs. I've not seen any.
You must open the head bolt holes to accomidate the 1/2" bolts used in the later engines. The 455s used 7/16" bolts. As previously stated, a simple process to fix it.

[olds]

The block flex is a thing of the past on the 403. Program machining makes a full girdle for it. Also, Dick Miller and J&S Machine make a halo girdle for it. CP and KB make pistions for the 403. The motor Dick Miller had at the EMC made 600HP. The block prep was done by J&S machine. 92 octane gas. Anyway..the 403 can be made to survive. There are plently of aftermarket parts now.

[Bandit79403Dave]

Here's a shot of the Program girdle...

We slammed the limiter at 7000 RPM with our 403...everything in the bottom end is in great shape. http://forums.performanceyears.com/groupee_common/emoticons/icon_smile.gif

http://memimage.cardomain.net/member_images/3/web/699000-699999/699737_74_full.jpg