NOT ANOTHER CAM THREAD!!

Red63440 · Feb 16, 2021

I bought an original 1970 383 HP short block with 20,000 miles, its all stock except for a Elgin Pro Stock E1053P cam and new lifters. Pistons are the stock 1970 383 magnum factory flat tops with a CR of 9.4 using a .020 steel head gasket. Engine ran well, no leaks or smoking. Heads are fresh 516 with new 2.08 /1.74 valves, guides and seals, springs, dampeners retainers and locks...heads were cleaned up .010 and runners were lightly touched up and a little gasket matching but nothing major. These heads were run on the 70 383 for about 1500 miles and ran well with no problems.
The 1970 383 engine is going to be installed in my 1964 Fury, my original 361 with 516 heads is still in place with a 727 push button transmission, power steering, power brakes and 3.55:1 peg leg installed which as some point will be changed out for 3.23:1 sure grip. I installed a Performer 383 intake and a new Edelbrock 650 carb and the car is still running its original log manifolds but with dual exhaust and I am hoping to purchase a set of 68/69 HP manifolds asap. It was recommended that a Lunanti 701 or 702 be installed but with all my reading I found that their cams can be hard on the valve train due to the fast ramps so like any other surgery you always get a second opinion.

I guess what I want to ask is what would I need to do to get about 400HP if possible based in the limitations. What cam could I use with what I already have that would be street friendly cruiser and still use stock rocker gear, converter? Attached is a photo of the cam box for the cam that is now in the 1970 383 HP block. I know that 383's can be ruined due to an over sized cam which is why I have posted this thread. A photo of the Elgin cam box is show below.

64fury74charger · Feb 16, 2021

Just a question, what is wrong with the 361 that's currently in the 64. Mine seems to do pretty well and has those "log" manifolds dumping into 2.5 inch duals with glass packs and moves very well. I am not sure how much you would gain without going up to a 400 based stroker or a 440. Not trying to start anything here, just curious.

:thumbsup:

4mulas · Feb 16, 2021

You pretty much have a stock magnum camshaft with a little more duration on the intake. So about 330hp now.
Things like intakes, headers, carburation may get you a few extra hp. But if you want 400 probably more cam for starters.

Red63440 · Feb 16, 2021

That’s why I posted.....I am getting fouled plugs and smoke and the engine is using oil due to the wear on the engine which is why the 383 will be an upgrade.

Red63440 · Feb 16, 2021

64fury74charger said:
Just a question, what is wrong with the 361 that's currently in the 64. Mine seems to do pretty well and has those "log" manifolds dumping into 2.5 inch duals with glass packs and moves very well. I am not sure how much you would gain without going up to a 400 based stroker or a 440. Not trying to start anything here, just curious.

View attachment 1070217

I’m not interested in a stroker, more cam is what I would like to add but I want to make sure the power brakes work well with it.

64fury74charger · Feb 16, 2021

Red63440 said:
I’m not interested in a stroker, more cam is what I would like to add but I want to make sure the power brakes work well with it.

Ok, I also read your other post describing the issues with your 361 so now I understand what you want to do. Camshafts can be a balancing act concerning vacuum and idle quality.
There are plenty of more experienced people here who can help with information and suggestions.

My 361 has a “mild” mopar purple cam and still makes around 17” at idle so there is good vacuum for the booster. I do not have the specific info on the cam, but it sure makes a difference.

Red63440 · Feb 16, 2021

Meet Mabel...

furious70 · Feb 16, 2021

If you read the moparts tech archives you'll see you're giving up power with those 516's vs 906.
The classic 383 resto to rad article found online shows you what each hop up piece does to power output.

forphorty · Feb 16, 2021

The Elgin cam you have now looks like it would a nice cam for a mild 383. As mentioned above, probably similar performance to stock 383 Magnum. If you are married to the stock torque converter, I would stay with the Elgin. If you want 400 hp you will need more cam . A typical 400 hp 383 is going to want more stall than the stock converter.

Red63440 · Feb 16, 2021

furious70 said:
If you read the moparts tech archives you'll see you're giving up power with those 516's vs 906.
The classic 383 resto to rad article found online shows you what each hop up piece does to power output.

I read that and they did a fresh rebuild on a 383 which I am not doing, I want a better cam that gives me more horsepower/torque. Using 906 heads would destroy the compression ration compared to the closed chambered heads, not building a drag car just a street car with a little more giddy up.. :praying:

Nate S · Feb 16, 2021

I agree with above. 400 hp can certainly be done but you’ll need a fully matching system for it to be fun. It won’t be just cam though.

You’ll need headers. Somwhere out there is a dyno test where they went from ‘64 log manifolds (best logs out there) to ‘69 hp on a 440, got them about 3 hp, on a 383 they are probably worth 2. Headers.

You’ll want a converter. 11-3/4 like a roadrunner, maybe a little less.

Keep the 3.55:1

I’d go for a cam with 230 at .050, much past that and it’ll push your needed rpm even higher.

516 heads with 1.74 valves don’t flow much better than 1.6 without some port work. The compression is nice but the flow of a ‘906 or later will be better, can always mill them a bit.

Your intake will be ok but you’ll probably need more cfm in the carb.

That will get you around 400 hp and be decent to drive.

Windage tray maybe too but it won’t fit with that crooked ‘64 pickup and odd oil pan.

If you figure a 383 rr is 335, you probably lose 10 on the heads and 2 on the manifolds. Cam is about the same so figure if you use the intake and carb from the 361 you probably have 320 today.

Red63440 · Feb 16, 2021

Oil pan from the 361 can be used on the 383 as can the 361 pick up and 383

windage tray, it may need trimmed but the bolt spacing is the same, 383 oil pan

can't be used because of the location of the K member. The carb can

always be changed based on the needs of the engine and while 400 is the goal I can

settle for less. The intake will swap over to the 383 as will several other parts that

will be needed. As far as the heads are concerned it would make more sense to buy

a set of Estreet 75cc heads than to buy 906 heads and have them rebuilt and have

both faces milled and the flow would be much better than both.

I appreciate the input....

furious70 · Feb 16, 2021

I referenced 906's since it's a later engine.
I've used 906/452/516's on the same 383. It was strongest with the 906, validated by the flow tests. Worst was the 516's, and they also had a 1.74.
516's rarely actually give you much cr stock. Have you cc'ed them?
And sure, let's go with new aluminum, didn't sound like they was an option to you.

Babyblue66 · Feb 16, 2021

I just had a 383 dynoed today I built for a friend. Forged flat tops about 10 thou down, with 906 heads came out to 8.8 to 1 with fel pro gaskets. Heads have 2.14, 1.81 stainless valves, I touched up the valve pockets a bit with a die grinder. It's balanced, has a windage tray, stock 1970 intake, 750 quick fuel carb. Cam is a Comp Xe268. I recurved the mopar performance distributor too. With headers it made 382hp and 421 ft lbs torque. 20 thou Steel head gaskets and a better intake would get it close to 400 hp.

Babyblue66 · Feb 16, 2021

That Elgin cam isn't a bad cam. It would run really nice in a 383, just won't get you 400 hp. Would probably be pretty responsive and make decent torque. I thought this 383 I built would make 350 hp and would've been happy with that. I did degree the cam and installed it 2 degrees advanced from comps recommendation since the compression wasn't very high. Looking for a certain hp number can be disappointing at times. And unless you dyno it, you'll never know anyway. I think your heads will be your limitation. Especially if there's no porting done. You'll have to go with more cam than I did, which means less vacuum and more stall. Definitely headers and a good 750 carb.

PRHeads · Feb 17, 2021

For the most part, if headers aren’t part of the upgrade plans...... and the cam choice will revolve around a stock converter and 3.23’s........ there isn’t going to be any cam that by itself will transform that combo into a 400hp package.
I’d forget about the hp number, and just make sure all the parts are on the same page...... and I’d say they currently are.

A newer design faster rate cam would bump up the power “some”, but will likely come at the expense of some added noise.
To still be compatible with your current plans, I wouldn’t go any bigger than the XE262 or Lunati 702.

Make sure the springs are up to the task, and that there is adequate retainer to seal clearance.

If you’re serious about trying to eek a bit more power out of it, pull the heads, do some bowl blending, and CC the heads.
Those things are often in the 84cc range, so the CR may not be what you think it is.

Red63440 · Feb 17, 2021

Guess I may have to re-think my goals.....

Nate S · Feb 17, 2021

Red63440 said:
Guess I may have to re-think my goals.....

Good time to think about all of it. Once you’ve committed to a path it’s tougher and more expensive to change. Big horsepower is cool but many of these cars were quite fun when stock.

Red63440 · Feb 17, 2021

My original concerns are still there and they still need to be addressed to make it "Fun" as you put it. The heads have never been off the 361 based on what the previous owner had told me so I am guessing the seals are gone based on when it smokes....more to come.

Red63440 · Feb 17, 2021

PRHeads said:
For the most part, if headers aren’t part of the upgrade plans...... and the cam choice will revolve around a stock converter and 3.23’s........ there isn’t going to be any cam that by itself will transform that combo into a 400hp package.
I’d forget about the hp number, and just make sure all the parts are on the same page...... and I’d say they currently are.

A newer design faster rate cam would bump up the power “some”, but will likely come at the expense of some added noise.
To still be compatible with your current plans, I wouldn’t go any bigger than the XE262 or Lunati 702.

Make sure the springs are up to the task, and that there is adequate retainer to seal clearance.

If you’re serious about trying to eek a bit more power out of it, pull the heads, do some bowl blending, and CC the heads.
Those things are often in the 84cc range, so the CR may not be what you think it is.

I am aware it takes more than a cam to change things and if you read my OP again you will see what I said that I would like to get as close to 400 IF possible based on the limitations, nowhere did I say it was written in stone.

NOT ANOTHER CAM THREAD!!

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