Ratdog442

just bought this car. upon checking everything the block comes up as a 69 but with 5a heads. according to previous owner the motor has a "rv cam" and had a 3 angle valve job. it has a edlebrock manifold and a holly 650. can anyone give me insight on why the 5a heads? the guy i bought from didn't have the work done it was the guy he bought it from. i have been running through threads to see if i can find a answer but nothing. thanks in advance.

olds 307 and 403

I am assuming the letter and number are the same size? I believe there were some rare 5 with a smaller A. I am betting they are the 80-85 Olds 307 heads, there will probably be bushings under your 7/16" head bolts but maybe not, I ran them without. The 307 heads have smaller ports, small 1.75"/1.5" valves, 67 cc chambers and 1/2" head bolts. Decent for a truck, not a performance car.

Ratdog442

what are the pros and cons?

olds 307 and 403

OK performance in the low rpm's with the 307 heads, choked at higher rpms. The stock 64-72 heads flow much better especially at higher rpms. Add 2.07/1.625" valves with opening the bowls for the larger valves for even bigger gains. All the 73+ Olds V8 heads have terrible exhaust ports without porting.

Ratdog442

with the 3 angle valve job would/could the ports have been opened up?

olds 307 and 403

Maybe but unless 350 valves were used, it will only help so much. How is the performance of the car?

Ratdog442

For a pig it is pretty good. I am going to bring her to the track to get some baseline numbers. I eventually will get the car dyno tuned to get as much out of what is there.

It has either a 3.42 or 3.73 posi, I am pretty sure it is a 3.73. I am going to upgrade the trans to either a 200r4 or 700r4 with a shift kit. Right now the trans shifts like a Cadillac...which is fine but I am used to breaking the tires loose under medium to high open throttle.

I bought it as a cruiser. Because of the later model heads I am guessing running regular pump gas should suffice...opinion?

olds 307 and 403

Even if it has 6cc dish pistons, if Felpro head gaskets were used you would have 9 to 1 compression, fine for regular. Are the 5 and the A the same size? I believe the casting # is 3317 on 307 heads above the center exhaust port. Go with the 2004R, easier swap and better gear ratios.

80 Rocket

You mean the throat area? A 3 angle valve job means nothing really. It's just a term that get loosely thrown around. The stock factory valve job was a 3 angle. It is a 0-45-90. Even if the typical 30-45-60 3 angle valve job is performed, there is no way to quantify how good it is. Seat width comes into play, valve size, throat area, the width of the other angles.


If you put a 2.07 valve in a 350 and your bottom cut is a 60, your throat will be way too small.


Don't take any of this like I am getting on you, just letting you know the answer to your question is "possibly", but that still doesn't tell you anything.


What will tell you more is this......what is the actual casting number of your head? Is it 397742 or 3317?

Ratdog442

397742.

No worries. I bought it this way. I am going to try and find the guy who did the build. It runs good just wondering the motivation to put 5a heads on this motor. From what I found the heads are good for power up to 5000 RPM then fall flat. The heads have to be better than the heads from 73 on??

The other question that has arisen in my mind is the exhaust manifolds. They are stock. Would these be the manifolds off a 307? If I decide to get headers, do I search for headers for a 307? Also will I get much gain?

Thanks for the input.

Ratdog442

397742 is the casting.

This may change things??

http://wildaboutcarsonline.com/membe...er_Head_ID.pdf

olds 307 and 403

Sounds like you have the rare 5A heads that match your block, much better than 307 heads. You need to figure out what head work, pistons and cam are in it.

Ratdog442

that is my mission. with that being said when you say rare...how rare?

Fun71

My engine used to do that when it had the original valve springs - the valves would float at 5000 and the engine would fall on its face. After installing a new set of springs, it went to 5800 easily.

Ratdog442

the block was bored .30 over. So assuming the pistons were changed out. tracked prior owner down via facebook. waiting for a response. He goes by the user name of 7071GS on ebay. Anyone know him?

olds 307 and 403

I haven't heard of many sets with the A on them. I think otherwise they are basically the same as regular #5 heads. Hopefully he didn't put in big dish cast pistons. I don't recognize the user name.

80 Rocket

Rick Finsta on this site has a set on his engine. I don't think there are any differences.

Ratdog442

I am getting closer to specs on the rebuild. I received a message from 7071GS. He sold the car for his brother on ebay. He is going to get me the number of the guy who did the build.

Rick Finsta

I know of no other differences between the 397742 (#5) and 397742A (#5A) other than the numbers - they were cast at a different facility is my understanding.

junior supercar

yep. have a pair on a 69 350 with only 62K miles and the motor has never been apart so I know they are original.

They look just like the pic Rick posted, only mine are still the original gold ... with some grease/oil

1BOSS83

No, search for headers for the car itself. 307, 330, 350 etc will all use the same header. You will have a noticeable improvement over stock manifolds. How much? You'll feel it in the seat of your pants.

olds 307 and 403

Those heads would be great on a 350 in a 83/84 Hurst /Olds or 85 442. Same size A, interesting.

Ratdog442

I found out that the block and heads came out of a 1969 Olds 442. That is when the motor was redone. According to the specs of this motor it was at 10.5 compression ratio.

My question, is this motor still 10.5 compression ratio?

Fun71

Unless it is a 400 cid engine, then it was not originally out of a '69 442. The 350 engine was not used in a 442 until 1972 with the introduction of the "442 option" as an appearance and handling package.

olds 307 and 403

If Flat top pistons were used it could have anywhere from high 9's to low 10's for compression. For one, factory head gaskets were .017" compared to .039-.041" for Felpro replacements. The factory 10.5 to 1 spec was set on certain numbers, actual measurement numbers were usually larger, meaning less compression..

Ratdog442

Flat top pistons were used. So I am good with using 87 octane? What about using any additives? Thanks.

Ratdog442

I saw that on 442.com, I am going by what the guy told me who made the mods to the car. It could be a donor from another car? None the less it is a 69 350 which is far better than a 73 350.

Magna86

You need to run atleast 91 but 93 if you have it. 87 will detonate and ping

Ratdog442

What if I am road tripping? Could I get away with the lower octane if I am driving at highway speed and not doing stop ang go?

Fun71

Yes, that engine would have been used in all 1969 350 applications. Since all 442s came with the 400 that year, it would have been transplanted.

Do you know what cam is in the engine? The valve opening/closing events will have a huge impact on cylinder pressure, which then dictates the octane requirements of the fuel. Two engines with the same static compression ratio can have very different octane needs due to camshaft differences.

Ratdog442

I am pretty positive it is a performance plus edelbrock cam shaft. I am guessing because the prior owner said it had a "RV" cam and it has a edelbrock performer manifold.

olds 307 and 403

I run that cam with 9.5 to 1, pings at times on 91. I even added 1.72 to 1 roller rockers and very cold NGK 5670-8 plugs. I am dropping my compression to 9 to 1, otherwise the same.

Fun71

If that is the cam in there, according to Edelbrock it is a 204/214 cam. That is the type of cam that would work well in a factory 8:1 engine.

Ratdog442

I asked both prior owners what octane gas they used and both said 87. The guy I purchased from said 87 no ethanol. I have been using premium with no issues but don't want to pay premium unless it is necessary. Thanks for your input.

88 Cutty Classic

why would you not want to use premium, especially on a a highway trip. the increase in gas mileage should more than cover the difference in fuel costs. a trip is where you would see it the most. i will never understand the logic of having an engine or car worth thousands and 10s of thousands and then get cheap on gas or tires, etc.

Ratdog442

Well the difference in A grade premium and regular is approximately 60 to 70 cents a gallon. On one tank that is $12-14 dollars. If the engine needs that I will spend it, if not I won't. I wouldn't have had the funds to buy this vehicle if I didn't apply this logic to all my purchases.

88 Cutty Classic

how often do you drive the car? i mean i have a simple way to justify it for me. if several hundred dollars over the course of the summer in gas is that much of an issue, then the car is a luxury and i probably shouldnt own it. you see what i'm trying to say here? if i have a car worth , lets say 10,000 and i drive it in my free time in the warm months.. if the difference in that time is 200-500 dollars over the price of 87.. thats a no brainer. yes $500 is a lot ....but then again its in this hobby. nothing wrong with making smart purchases but dont try to find ways around giving the car what it needs. as i said in my last post, high octane is a better bang for the buck on the highway. its all the best time to use it too as the steady rpms of a high trip and high grade gas will help clean out the carbon buildup.

60-70 cents seems excessive. in my area its about .40 cents. if my 18 gallon tank was bone dry thats 7.20 difference. thats 13.8 fill ups before i;m at $100 difference.

i mean if you drive the car pretty often, you are stuck if your budget can only do 87. With as much garbage as they put in our gas today, thats even more reason to run premium in my opinion. There is one surefire way to test it for your application when you take a trip. try a tank of 87, try a tank of 93 and compare the MPG and then calculate if its worth the price difference. good luck!

olds 307 and 403

There is no way your car has the 3712 cam with 9.7 to 1 or even more compression and not ping like hell unless you live in the mountains.

Ratdog442

I don't know if it does or doesn't. I bought the car and what was disclosed is the car has a RV cam. Maybe it does maybe it doesn't. What I do know is it has 69 olds 350 motor with a performer intake, a holley carb and a 3.73 gear with a eaton posi.

I am bringing the car to the track May 10th to see what kind of 1/4 mile times it runs. I plan on getting the car dyno tuned to get the most out of what is there at some point. I have been running premium fuel since I bought the car but just filled up with regular to see what happens. If it starts pinging then I know I need to use premium grade.