lansing

Would like to get opinions, recommendations on aluminum intake, carb, and camshaft for my 65 425 engine.
It is the high compression motor and currently has stock 2 barrel carb and manifold. It has the 45 degree cam angle. I wanted to do a complete rebuild but budget will not allow at this time, so just upgrading a little. Engine has 32,000 miles on it and is in good shape. I will have to stay with factory dual exhaust manifolds as it is going in a 65 B body. Maybe a mild camshaft is not even worth it?? And the 45 degree version is certainly not easy to find. (I think Mark R can get me one but ....will it increase performance enough to justify doing? Any suggestions on which manifold and carb to use?
Thanks for any input.

don71

I'd probably do a edelbrock performer and a quadrajet carb. I'd skip doing the cam for now. I'm not sure about any issues with the carb linkage but it might need to be sorted out, with some adaption.

I'll make an assumption that the engine is out of the car, if that is the case, I'd ensure new gaskets where necessary and new frost/casting plugs too.

olds 307 and 403

Anyone have the specs for a 425 2 barrel cam? You more than likely need a timing set done at minimum. Yeah the Performer intake and a custom calibrated 76 to 80 800 cfm Qjet converted to electric choke.

matt69olds

If the engine really has 32000 miles, it probably needs nothing more than just resealed and a few go fast goodies.

Do a leak down test, check the compression, if all checks good then add some upgrades. Install a new timing set, and swap in a modern camshaft, find a factory 4 barrel manifold, or preferably a aftermarket aluminum. Get a Q-Jet built by someone who knows what they are doing, and start saving for lots of tires.

BillK

If you do decide to do a cam Erson had some 45 degree cores. They just ground one for me for a 65 425 I am doing. It is pretty mild. .428 lift. I just needed a camshaft and didn't want anything crazy.

lansing

Did leak down and compression and all is good. Have driven the car with this motor, no smoke, no blow by and runs very well. (my wife says "LEAVE IT ALONE!" Just clean it up and drive it!) She may be right, but that's never stopped me before!
Of course I will replace timing chain and gears, freeze plugs, gaskets, etc. just for peace of mind.
Q Jet has been mentioned a couple of times. Any names of rebuilders who know what they are doing? Had a 4GC rebuilt a couple years ago, kind of turned into a bad dream....not a full blown nightmare, but still....

lansing

Thanks Bill. I've so far just been checking websites for availability, I probably need to give them a call. So that means I gotta make up my mind whether to change cam or not!

NTXOlds

There is a lot of great advice here. If I were you, I would probably just install an Edelbrock Performer RPM intake and a good Quadrajet (or 4bbl Holley if that is your thing) and drive it around to see how much extra power it has. It is the easiest and least expensive option, and you would want to do these if you were to change cams anyway. You might find that this is all you really need to do until you do a full engine rebuild.

According to the Oldsmobile Junction website, all 425s, both 2bbl and 4bbl, used the same cam except for the Starfire.

If you cam is factory, it would have the following specs:
Year Part. Overlap Int./Exh. Dur. Int./Exh. Lift. Applications
1965 387484 52 278/282 .430/.432 400, 330 4BC ST,425 ex Starfire

https://oldsjunction.classicoldsmobi...sfaq/ofcam.htm

BillK

I hate to say it but I would agree with the Wife

jmcghee

I do believe a 2 barrel 425 is low compression

GCH

+1

The 425 2 barrel in my Dynamic 88 -65 is " ultra high compression".

BillK

They are pretty hard to get in touch with lately. Everyone is pretty short handed. If you do decide to go that route let me know and I will get in touch with them. I buy 99% of my engine parts from their parent company PBM performance.

I think Mark uses their cams also so either one of us should be able to get in touch with them.

lansing

Thanks to all for your input, and thanks Bill for your offer to help out with cam. Now I just have to make up my mind!

matt69olds

Your wife says leave it alone. How many pairs of shoes does she own? How many pairs of feet? I rest my case.

Stock is boring!!! Slip in a cam that lets everyone know you have some testosterone!! You don’t need a bottom of the page, rattle the fenders off the car, but something with just a little authority.

lansing

I like the way you think!!

cutlassefi

Just an FYI for all, there aren’t any “45* cores”. They’re all based on a 39. Bill, whoever told you that is wrong. They need to stop saying that. That would imply that you can do any grind on a 45 that you can on a 39. You can’t.
There are two things that dictate whether or not they can grind a 45* cam on what is technically a 39* core. First is the amount of raw stock on the core itself. Second is the actual lobes and lsa chosen. All Olds cores are like this, roller or flat tappet. The only “different” core would be for an alternate firing order, again whether it’s a roller or flat tappet.
Op I can help with a cam as well whenever you’re ready.
Thanks.

lansing

Thanks Mark. What's your opinion on doing a cam in the above mentioned 425 with cast iron exhaust manifolds? I think there is probably performance to be gained with a new cam, but I'm not sure how much. Also I don't want to go too big with the cam as it would just be a waste if it exceeds what the motor can handle flow wise. I want to try and hit the sweet spot if I do go ahead with cam change.

lansing

Also should mention stock A heads, TH400 switch pitch trans, and the car will have AC

cutlassefi

If you do it as a package then yes I believe you would see a benefit. Add a properly tuned 750 vacuum sec carb and you’ll be on your way.

Fun71

Here's a period correct QJet carb for sale at a reasonable price:

https://classicoldsmobile.com/forums...nifold-157302/