383 HP - cam selection for hot street / highway

[451Mopar]

This.

OP- view everything you get here as rough, general guidelines. There are so many interconnected variables even asking the professionals at cam companies that do this for a living will give you different responses and recommendations. Sometimes very different.

And, the most complicated key variables are all you. It is the nature of a street car and balancing the personal priorities.

Let’s visit them. “Street”, “light strip”, “cruising”, “efficient”.

We have no idea what those things mean to you. I can spec a 100 cams to do those things, from stock to roller cams with 0.700” lift, depending on what on what those things mean to an individual.

Every decision you make on one variable will be a compromise on another.

Pick 5 cam companies. Fill out their cam questionnaire form, and see what recommendations you get back. Post them here. That’ll be fun.

There is even issues filling out cam questionnaire, as most don't ask alot of technical questions that they (usually) correctly assume the buyer won't have like port flow and velocity numbers, correctly calculated compression ratios, intake and exhaust design and flow, so the cam company has to make assumptions for you, and many times they might just look up a shelf cam, unless you tell them you want a custom cam specific to your application.
You also need to be careful when comparing "Dyno" result numbers. You don't drive or race dynos they are just a tool, and usually the engines are tested on a 300 RPM/second sweep at wide open throttle before even starting the test. Also, the guys doing dyno tests often consider a cam with "low end torque" means torque around 3,000 RPM, not "low end torque" many refer to as being around 1,500 RPM. On the Dyno, they usually don't consider idle quality or vacuum, or how the engine behaves under prolonged loading like a towing engine.

Really, with a near stock engine and drive train I would likely select a cam like the Comp 262/270 advertised duration, 218/224 @ 0.050" duration 0.462"/0.470" lift, 110 LSA and if I wanted more lift, run a 1.6:1 rocker arm.
The Summit Racing K6420 213/225 @ 0.050" with 115 LSA duration seems close to the factory magnum cam?

 

[Geoff 2]

Some cam grinders RARELY used dual pattern cams. Isky is one. The MP cams are nearly all single pattern cams, whereas many of the production cams were dual pattern. So what gives? I suspect cam grinders expect the car owners to get rid of the inefficient exh manifolds & install headers which apart from having better flow also provide wave tuning. Kills two birds with one stone.
Here is what Isky says about extra exh duration.

 

[oldkimmer]

Instead of a cam change a converter is the best bang for the buck. It can make a night and day difference. As long as you’re honest with the converter company. Kim

 

[MikeyM]

Thanks Kim,

I haven't gotten a chance to "test" my stall in the current TC but I think it's a replacement which should be 24-2600 according to the FSM?? If so, (and I know not much about performance TCs) would a different stall speed be more favorable if the duration is kept to under 230ish @ .050?

Thanks
Mikey

 

[oldkimmer]

Thanks Kim,

I haven't gotten a chance to "test" my stall in the current TC but I think it's a replacement which should be 24-2600 according to the FSM?? If so, (and I know not much about performance TCs) would a different stall speed be more favorable if the duration is kept to under 230ish @ .050?

Thanks
Mikey

Yes a good 9.5 inch converter 3500 or more stall will drive like factory till u hit the loud pedal then hang on. Kim

 

[451Mopar]

Yes a good 9.5 inch converter 3500 or more stall will drive like factory till u hit the loud pedal then hang on. Kim

The Charger has a 9" Ultimate converter that I had built to be "tight" for street driving, and it drives like stock until you get on it, then flash stalls around 5,000 RPM.
It is nice for my application with street driving. For drag racing, because it is so tight, it dosen't hit as hard off the line as looser converters I have had.
When I bought it, I could have sent it in to have it adjusted. It was pricy, I think around $1,200 but it does what I wanted it to do.

Custom Torque Converters for Drag Racing - Ultimate Converter Concepts

 

[dart4forte]

Yes a good 9.5 inch converter 3500 or more stall will drive like factory till u hit the loud pedal then hang on. Kim

Yeah, but what about heat?

 

[oldkimmer]

Yeah, but what about heat?

A good tranny cooler will take the heat. The new age converters drive like a stock converter till u need it. Best bang for the buck for the op. Kim

 

[MikeyM]

Awesome. Super good to know. Thanks Kim.

Mikey

 

[MikeyM]

I have heard a lot recently about TCs and how they could be "tight", smaller in diameter, allow for taller gears like my 3.23s, yet allow the low end performance to be pretty phenomenal while acting mostly stock and allowing for good drivability.

Kim and 451, would you kindly enlighten me why that is?

Thanks,
Mikey

 

[BSB67]

……while acting mostly stock and allowing for good drivability.

Folks are always saying today’s 3000 stall converters are just like stock. Well, they are not. Depending one’s situation, they may seem more, or less than “stock like” based on these factors:

1) What you believe and/or think stock is,
2) The specifics of your car and drive train,
3) Where and how you drive your car.

Collectively, these factors will affect the feel of the driving experience. What some folks like, others might not. It’s a personal thing.

 

[451Mopar]

I have heard a lot recently about TCs and how they could be "tight", smaller in diameter, allow for taller gears like my 3.23s, yet allow the low end performance to be pretty phenomenal while acting mostly stock and allowing for good drivability.

Kim and 451, would you kindly enlighten me why that is?

Thanks,
Mikey

I originally has a traditional 10" High stall converter that was sort of "loose" where it would want to spin up to 3,000-3,500 with smaller throttle input.
I didn't know about the "tight" converters until I spoke to Lenny at Ultimate Converters. I don't know the specifics on how it all works, I think custom stators and such are part of it.
Call them and ask the professionals.

 

[dbc105]

Hot cam for Street and Highway has gone a bit off topic hasn't it? He said "I'd also like as much low end as possible while still retaining good highway power with 3.23s and a stock converter." Not really sure how a Stall Converter is going to help anything on the highway except maybe slip while cruising killing gas mileage. Good luck.

 

[451Mopar]

Hot cam for Street and Highway has gone a bit off topic hasn't it? He said "I'd also like as much low end as possible while still retaining good highway power with 3.23s and a stock converter." Not really sure how a Stall Converter is going to help anything on the highway except maybe slip while cruising killing gas mileage. Good luck.

Post #61, Comp 262/270

 

[matthon]

I'm a big dummy when it comes to cam selection and engine building and junk like that, but when I had my 383 built 100 years ago the engine builder set me straight.

I brought him the coveted 915 heads, he tore them down and said they're in good shape but I'd be stupid to not buy new aluminum heads.

Iirc in this thread spending the $ on aluminum heads was only mentioned twice, by the same person.

Wouldn't it be better to start with/spend the $ on the heads, or should I call my engine builder back, lol.

 

[451Mopar]

I'm a big dummy when it comes to cam selection and engine building and junk like that, but when I had my 383 built 100 years ago the engine builder set me straight.

I brought him the coveted 915 heads, he tore them down and said they're in good shape but I'd be stupid to not buy new aluminum heads.

Iirc in this thread spending the $ on aluminum heads was only mentioned twice, by the same person.

Wouldn't it be better to start with/spend the $ on the heads, or should I call my engine builder back, lol.

There are alot of considerations. If you are looking for performance gains than aluminum heads can get you there easier.
The cost side depends on what parts and machine work the iron heads need. If they need hardened exhaust seats, new valves and guides, cleaning, surfacing and such it is easy to be $800+ into the stock heads that flow stock airflow numbers, so you end up about 1/2 way into the cost of aluminum heads that have larger stainless steel valves and higher flowing ports.
Now if performance is not a factor and you want closer to stock performance and appearance, then the iron heads can save money.
There are other factors too, like the weight difference, chamber designs, spark plug angle/location, and valve train requirements (some of the race type heads need offset rocker arms.)
There is also how reparable the heads are. Usually aluminum heads can be welded and repaired if something happens like a dropped valve. With iron heads you might have to worry about cracking although I haven't had that problem, but I never put oversized valves in the iron heads I had.
Anyhow, both iron and aluminum have their place.
The aluminum heads do have hidden costs, like requiring new head bolts with the smaller wrench head size, Some heads may require different length head bolts or studs also.
As mentioned earlier, some of the high performance heads require offset rocker arms.
Also, I disassemble the new heads to clean them, and check clearances and valve job. Not a big deal as usually have to change valve springs to match the cam anyhow.

Back to the cam. For a street car you are doing most of your actual driving under 3,000 RPM, and usually full throttle shift points are around 5,500 RPM.
The assumptions are you still want good engine vacuum, and decent low end torque (low end being in the area of 1,500 to 2,000) for use with a stock torque converter. Other considerations are low maintenance.
I actually like the Hughes engines cams, but they stopped making them. The comp cam was just a quick selection of off the shelf cams, but it is worth pointing out just how different the cam timing is compared to some of the other magnum replacement cams that have about the same durations. Need to cut this short as i have to go, but the narrower LSA increases overlap and the cam is installed in a more advanced position so the actual valve opening and closing events are quite a bit different than the wider LSA replacement cams.

 

[Middleagecrisis]

A quality 11” converter won’t affect drivability and will greatly improve off idle performance, even with your stock cam. Run a trans cooler to keep your trans happy. I had very good results on a set of 906 heads I ported years ago using the Mopar bowl porting template. Not sure if that’s available anymore, but it tells you exactly where to port and how much to take out. I was on the Hughes website a few weeks ago and they stated they were no longer producing hydraulic flat type of cams. Personally, I would stay away from comp cams and stick with Isky, Crower, or some of the purple cams that you can find them. If you’re looking for budget cams, look at some of the summit racing offerings. I’ve used them and never had problems. I highly recommend you get your factory lifters refaced. I’m also over on FABO and the member NC engine builder will reface them in his shop for approximately $80 for the set plus shipping. He’s done several sets for me in the turnaround time is great! With your 323 gears, even with an 11 inch converter, I would not go over. ~224 @ .050 duration on the camshaft. You’ll need the proper springs for whatever cam you chose, so unless you’re comfortable setting up the spring height, I would have your Machine Shop do that for you. They can also check your retainer to valve guide clearance and setting up the springs. Just my .02 worth.

 

[Middleagecrisis]

I'm a big dummy when it comes to cam selection and engine building and junk like that, but when I had my 383 built 100 years ago the engine builder set me straight.

I brought him the coveted 915 heads, he tore them down and said they're in good shape but I'd be stupid to not buy new aluminum heads.

Iirc in this thread spending the $ on aluminum heads was only mentioned twice, by the same person.

Wouldn't it be better to start with/spend the $ on the heads, or should I call my engine builder back, lol.

Aluminum heads are a great option, even for a mild motor if his heads need to be totally gone through. The Edelbrocks are very affordable and would give him great results. However, I’ve heard too many horror stories about quality problems with any of the aftermarket offerings, so he would be advised to take them to a Machine Shop and make sure everything is good and spring pressure is proper for whatever cam he chooses.