Hi all,

I'd been toying with the idea of replacing the 307 in my 1983 98 with something larger for some time. A few years ago while trolling the local u-pull yard, I came across a 1971 Cutlass with a 350 2 bbl. The engine was almost out, so I yanked it.

I haven't had the chance to check the bottom end, but that's another story. What I was able to determine is that I indeed had a 1971 350 with #7 heads.

The original 307 is still pretty healthy, leaving me lots of time to build an engine. The CCC system works perfectly in my car, and I intend to make it work with the 350. I know this has been done and have done the research to see what modifications are needed for the carb and the 200-4r. I know my cam choices are somewhat limited. Yes, I know I'm losing some power potential. I'm good with this.

My questions:

1. I will be using an A4 manifold so I can retain EGR. Will the 1971 heads be compatible? There was no information I could find to suggest there would be an issue. If I'm understanding correctly, the EGR is pulled from the crossover back into the intake, so as long as there's an exhaust crossover in the heads and other associated EGR equipment, it will work. Does that sound right?

2. I also intend to keep the AIR system. I haven't looked at the engine for a while, but as I recall, the #7 heads already had the AIR tube bosses. Do they just need to be drilled/tapped?

3. I'm not sure about the exhaust. I'd love to do a dual running down the passenger side so I can retain the cat. I have the stock 307 and the stock 350 exhaust manifolds. I know I need the 307 passenger side exhaust manifold for the O2 sensor. Is there any difference between the 1983 307 and 1971 350 driver's side exhaust manifold?

4. Any other concerns? Suggestions?

 

The A4 will work fine. Dump the air system as the computer will work fine, remove the pump and no worries plugging the line to the cat if you change the exhaust. The exhaust manifolds exit different but interchange. Are you totally rebuilding the 350? If so, use the LF2321 pistons and a custom cam from Cutlassefi.

 

Thanks for the input! When I'm getting closer to getting this engine apart, I'll get in touch with Cutlassefi. I would be likely be doing a complete rebuild. I have no idea what condition the engine is in. I will pull the pan and have a look. I have a feeling this engine hasn't run in a long time. When I took it home and looked it over for the first time, I noticed the upper radiator hose was stamped 1992.

As I said in the original post, I want to keep the A.I.R. system or at least be able to install it. That said, it looks like the #7 heads have the bosses which I should be able to have drilled/tapped.

What about carb modifications? I'm sure the secondary rods need to be changed, but what about the primary side? I've heard that the idle passages and jets are a little lean for a 350. I've also heard of some people
removing the idle tubes and installing the larger ones available from Cliff Ruggles. With a custom cam, is that necessary?

Thanks again!

 

May I ask why? When I read your first post I actually looked in to the AZ restrictions on emissions. (Post 66' if anyone is curious )

 

This car is not being tested due to having collector car insurance. However, with a new drive line in the future, I may decide to turn it into a daily driver and intend to play by the rules if I do. I want that option available to me.

I spoke to an acquaintance once who works at a test station and he told me they WILL check to see if the AIR system is present.

As an aside, he also told me they won't care if they see more than one converter underneath, as long as there are converters.

 

Yes, new idle tubes and larger primary jets are a good idea but I believe the jets are unique to the electronic carb and hard to find. I would rebuild the motor with 6cc dish Speedpro LF2321 in probably a .030" oversize.

 

Yes, the jets are unique to the CCC carbs, so I don't know if there is a better jet than what I have.

I don't see a listing for an LF231 by speedpro, but the LF2321 made by Sealed Power looks to be the right one.

http://www.summitracing.com/search/p...7%2B4294951399

Is there a better source for the pistons?

 

http://www.ebay.com/itm/Speed-Pro-TR...VRQi6u&vxp=mtr

 

http://www.summitracing.com/parts/sl...ake/oldsmobile

Here is the 6 cc SP. I understand the desire to stay above board, I am also an honest abe. That said, I've passed the last 13 emissions tests with NO A.I.R system present; two different states, two different motors and if the kid who popped by hood knew what he was looking at I'd be shocked. I have cats and I threw a charcoal canister in there so she looks legit.

 

It sucks for the air system, we were non CCC up here till 86 but had the air system in 83. Those are pistons, if you don't 0 deck the block and only do a clean up on the heads and block with Felpro head gaskets will give low 9 to 1 compression. You will probably want a cam no tighter than 112 LSA and not much more than 215 duration. I know my 94 Olds powered 4x4 didn't care for the 204/214 cam with 114 LSA. Supposedly the factory TBI don't like cams over 210 duration with no tighter than 112 LSA. I believe the CCC setup is more forgiving cam wise.

 

I appreciate talking to someone that sees where I'm coming from! I wish AZ would dump emission tests for anything older than 25 years, but I doubt that will happen. Thankfully they passed the collector car rule about a decade ago.

This acquaintance of mine suggested that the emissions techs in AZ are well-trained. While they may not recognize some of the more odd emissions control devices my car has (VDV, ILC, etc), I'm not going to take my chances on the obvious.

 

Those numbers are very helpful. Thank you.

I've read that these cams might work, too. The first one seems to be good for a daily driver.

http://www.lunatipower.com/Product.aspx?id=4214&gid=258

Question: What would be the advantage/disadvantage of a cam that has different intake and exhaust duration/lift? The cam below has greater exhaust lift and duration. I'd lean away from this one as the RPM range is higher than the engine is going to operate.

http://www.lunatipower.com/Product.aspx?id=4216&gid=258

Thanks!

 

Not enough rust out there! You guys probably have 30-40 year old cars all over the place.

I'll chime in on your camshaft question. Camshafts selection is one of the most debated topic on CO. Knowing that, I'm going to share why I went with the camshaft I have in the H/O. I'm not taking it out so if another member jumps in and says what I did was incorrect or my theory is wrong, fine.

After doing a lot of reading on Oldsmobile heads I formed an opinion that stock iron heads don't flow all that well. Especially on the exhaust side. Knowing that, I was looking for a cam that had more off the seat time and more lift, I read that stock style heads don't flow very well past .500 (my heads are factory) so I went with .490 on the exhaust. I wanted more duration because I wasnt going to machine in larger valves. As a result I was better off keeping it open for as long as possible. The cam is on a 110LSA which gives me a fair amount of over lap (54*) which would aid in the scavenging. So my theory was: more over lap, more lift and more duration on the exhaust side would be a benefit for my combo:

Considering my car is geared for mid-mid high RPM I wasn't worried about the low end torque loss of my cam profile because of my driving style and factor'd synergy of trans, gear, tires, stall, etc.

Based on your other posts, and the sheer size of a delta, I am of the thought that it makes sense for you to be in the idle to 5k cam market place. Which one? Someone smarter than me will know.

I like this reference

http://www.442.com/oldsfaq/ofcam.htm

 

In theory that's true but the cam you picked doesn't do what you intended it to. That's a fast ramp cam, it won't give you the most off the seat time.
Plus if the flow plateaus at .500 or so you can push it just a bit past that. It spends very little time at peak lift anyway.


Just an fyi.

 

Thanks for the info Mark. I have a question about that I'll PM.

 

http://www.lunatipower.com/Product.aspx?id=4214&gid=258
This one you picked was the cam I was going to try in the TBI Olds powered 4x4. The other cam is basically the generic/Edelbrock Performer cam ground on a 112 LSA vs 114 LSA. I had the Melling version, had to turn up the idle screw and ran a bit rough in open loop but that was with a chebby timing curve. It would work OK but the one above his the one I would try.