74CS

So hello all of you Oldsmobile people. I am fairly new to this website I have however done one post already introducing my self and looking for parts.

Now I have a technical question and I am hoping someone can help me.

I have recently purchased a 1974 Oldsmobile Cutlass Supreme. I have wanted on for years because it is what I drove in high school. Anyways I want to change things up a little bit. I am trying for the 80’s style muscle car, this is a factory floor shift car and I have found a set of swivel front buck seats that I am putting in. I have already installed the air shocks on the rear and have the 15x8 US mags in the rear with 14x7 US mags in the front with raised white letter tires

Ok now for my technical issues. This car has the original 350 rocket motor this is the # on the front of the engine #357360038515398. I do not know which heads are on it although I am pretty positive it is all original

So now, I do NOT want to build a race car by no means I just want to add some goodies and get her to run a little better. This will be my daily driver

Therefore, I have already bought an HEI ignition set up for it. As well as I bought a 7111 performer RPM manifold. I have also bought a 1406 carburetor.

First, let me say I am not really a hot rod guy as I’m sure you can tell already

Now I did not really research the manifold before I bought it. I liked the way it looked and I got it for a good deal

Now what I am reading is that I need to run a thumper cam and a larger carburetor

Therefore, I am looking for some suggestions. Like can I run just an RV cam and my 1406 carb and still be able to tune her to be a good daily driver

In addition, I really do not want to change any of the valve train at this time.

Thanks in advance for any and all help with my new baby

Greg

2blu442

Hi Greg, welcome to the site! Are you thinking you'll need to change the cam to run the intake and carb? If so, I disagree. I believe that intake and carb would function fine with a stock cam shaft. Please clarify if that's the reason your looking for a different cam. John

captjim

The compression ration on that engine is around 8 to 1. This will limit cam options. If you put a big cam in it, it will have poor throttle response. The RPM intake is also not a good choice. IMO, you are better off with the factory 4 bbl intake. Also, those cars came with tall gears, usually in the 2.41 range. Again, this will limit what you can do.

The best thing about that engine is the 14 cc dished pistons. At some point in the future, replace the #8 heads (large chanber) with some slighly milled early heads (smaller chamber). That will bump Cr up around 9 to 1. Then you can upgrade the cam, intake, and add headers.

Another option is to find a running 455. Easy swap and the 500 ft/lbs will make it VERY fun to drive.

jpc647

I've got a 72 with a performer rpm intake and a 1406 carb. I've been killing myself trying to get it to run right. I either have umpff from a stop, and bad hesitation everywhere else, or nothing on the low end until 10mph and then the car goes like hell all the way up to about 80mph. At about 80 if I hit the gas, the secondaries open and it's runs like crap. Been screwing around with the carb for a month now. The intake is made for an engine that spools from 1500-6500. No stock rocket 350 will see more than 5000 rpms(max). I'm probably ditching the 1406 and intake and going back to oem.

74CS

As for 2blu442 question i actually wanted to change the cam and it is in the budget right now. In addition, I just thought to do it all at one time because I am going with a cam and lifter set. I was thinking like a mild RV cam maybe 470 or so. THANK YOU

As for you other guys You are great and kind of what I figured was going to be told to me after what I was reading

I just like this manifold so much AND IT IS BRAND NEW AS WELL AS PAID FOR dang it

Therefore, I guess I got some thinking to do before I start the tear down

texxas

I'd get your original quadrajet rebuilt (or do it yourself) before I'd run that Edelbrock 1406. The q-jets are more responsive off the line and get better fuel mileage in my opinion. I think the q-jets are great carbs when built and set up correctly. Good luck with your car.

ah64pilot

Is your engine stock? If so,you're asking a lot from a 40 year old set of stock valve springs. You are probably floating your valves around 4500 if you can't rev above 5000. Bolt on parts like intake and carb work for newer cars, but you cannot expect a 40 year old engine to say "YAY" when you put a new intake and carburetor on it unless you make some changes elsewhere.

Another problem is that your stock cam is designed to work with a stock intake. If you haven't changed any of that, then you are hurting your performance with a large plenum intake like the Performer RPM.

I know you like the manifold, but if it's not right for your engine it won't help it a bit. You can like the look of a Victor Jr. intake but if you put it on a stock 350 it will run like a turd.

Taken from Edelbrock:

"Performer RPMs have larger plenums and runners to match the free-flowing exhaust, high-lift cams, and other modifications of a high-output engine. They're intended for high performance street or competition engines that run from 1,500 to 6,500 rpm."

If your engine is stock elsewhere...I'm afraid you're not going to get much out of that intake but tuning problems. Why didn't you just go with the performer?

firefrost gold

http://www.ebay.com/itm/Edelbrock-US...16643931416147
This is what I would run If I had a SBO has a neat look and is time correct for your car. The edelbrock 1406 should work fine . You might have to get a jet kit
and set it up but they are easy to work on . Good luck

2blu442

Well it sounds like you've got some things to consider Greg. A few years back I purchased a 1972 Cutlass with the Performer RPM with a Holly 570 carb on it. I used it as a daily driver for about a year. It had a 2.78 rear end, 350 engine with a TH350 and the way I drove it spent most if its time between 1,000 and 2,500 rpm. If it had a cam it was a very mild one as it had a smooth idle. I don't remember having problems with it. Then on another car I had the Edelbrock 1406 carb on a stock intake, a 1968 350 engine. For a daily driver that functioned fine too. I have gone back to the Quadrajet as my favorite carburator though.

If your considering replacing the cam you might want to go back one more step and look at your goals for the car. captjim has a point of just plopping a 455 in there even at stock form you'll wake up your car. Or save up your money and do a complete rebuild on your 350 engine, changing the pistons and heads in the process.

Lots of options. But I'd encourage you to not lose sight of your goals. Plan how much money you want to spend. Plan what you want the car to do. Too often we get carried away with the "might as well" and wind up with something other than what we really wanted. When you have time read through the posts about what others have done to their engines. If you can find a local Oldsmobile club hang out with some other guys and see what they did to their engines. Maybe you can talk them into giving you a ride so you can see what the performance mods did for their cars. Good Luck on your build and make sure you have fun along the way! John

bigD

if nothing else put the intake on the shelf and start planning for a build project. if the car runs good continue to drive it as it is until you have the parts necessary to do it right. i'd go with flat top pistons, deck the block .020" or so (target .010" deck clearance) and have your heads rebuilt and milled .030" (generally on a sbo every .006" you remove from the head reduced chamber volume by 1cc).
for cams i like the comp cams stuff but there is a lot of good stuff out there. for your engine right now i'd run the 260H but built up a bit probably the 268H or 270 Magnum. i tend to run conservative on camshafts, in a street car that spends virtually all its time below 3k rpm all you need is a moderate jump in duration & lift... no sense in getting too carried away. i just did some work on my '70 350 this past winter and i installed a mondello/engle 16-18 cam and i really like it. has a nice rumble but pulls very strong. many consider it a small cam, 210/216 @ .050" and .474"/.488" for lift but when you consider that the factory cam is 190-195 @ .050" (at best) and .400"/.400" lift it is a good improvement over stock. especially with the 2.78 rear end ratio...

jpc647

I don't know what a stock Rocket 350 revs to, what I was saying is it not 6500 or anything near it, so the RPM intake isn't going to work well. Edelbrock told me to recalibrate the 1406 with different rods and springs. For the price of all new gaskets and the calibration kit, I can have a 72 quadrajet rebuilt to run like new. I don't know if the valves would be floating around 4500 rpms, but a stock 72 350 doesn't have a hole lot of guts. A Cam, an intake, headers, and a new carb seem like a lot of money and parts for a small bump in power. To me, it's not worth rebuilding a 350 will all new heads, etc. Without a major build, a 350 isn't going to put out any real power. I'm at the point I'm going to put the quadrajet and OEM intake back on the car, and probably sell it.

To the OP, from personal experience, do not use the RPM intake. AH64 is right, it's going to lead into all the tuning problems I currently have, and you'll never get it to run right. Ether it'll be a dog off the line, or a dog in the mid-high range.