408 Stroker Build Suggestions

[zsn0w]

Want some recommendations/advice on my build I'm starting up. I have the basics pretty much set, but some things (specifically the valvetrain) are still up in the air.
I'm aiming for a streetable car with a very good lowend that will be fun and fast but still drivable near daily. That being said, it doesn't have to be completely tame, just not looking for over 500HP or anything. I'm planning on using this kit https://www.summitracing.com/parts/sca-1-98113bi/overview/make/dodge for the rotating assembly as I want to be able to use it with pump gas and think the compression ratios look good here. For the intake I have an LD340 and I was planning on upgrading the carb to from my Holley 1850 I have laying around to a 750 CFM holley double pumper after saving up a bit. If this is overkill please let me know.
What I have questions about are head choices and valvetrain/camshaft options. I'm planning on keeping it a hydraulic flat tappet, and I was looking at Hughes SEH2428AL-11 and SEH2832AL-10 as options for the cam. My only problem with these is the questionable necessity of using all of the other hughes components. Pretty pricey for what, to me at least, seem like overkill for my usage. Could I use stock valvetrain components with this? Or at least stock-style summit lifters, springs, pushrods, etc? What other cams would you recommend? These cams seemed ideal in my research, but please let me know if I'm just completely barking up the wrong tree here.
On the topic of heads, I've been considering using 308's or maybe Edelbrocks if I can afford it and it's necessary. Would the 308s be a huge hindrance in a setup like this? Any input at all is appreciated. I have read a LOT about engine building but have not had much experience myself (yet), especially in the realm of V8s and pushrod valvetrains.
Thanks for your time and help!

 

[69 GTX]

You might ask Hemmirunner, he did a stroker sb not to long ago. I'm sure he could give you some pointers. BTW do not skimp on the valve train components!

 

[1967coronet440]

That’s what I was told by guys here and friends. Do not go cheap when it comes to valvetrain

 

[rumblefish360]

@zsn0w

Wow! Lots of questions to answer so I’ll knock them out one by one.

The Scat rotating kit is fine. Adding that many cubes over a stock 340/360 is a sizable jump. This has an effect on the cam size your looking at. Which leaves me to ask what exactly is the ride for? What gear ratio, tire size and the weight of the car is.

I myself would choose the larger cam because the jump in cubic inches tends to eat up cam duration. In other words, a cam feels smaller.

While it isn’t a necessity to use only Hughes components, it is not a bad idea. They are cheaper than the competitions. And they are really nice. You would also appreciate an adjustable valve train over the stock components. One of the benefits is that the aftermarket rockers hold a true ratio over the stamped stock parts which do not.

You are MUCH better off getting new properly size pushrods, new springs designed for the new cam which is way more aggressive over a stock unit and IMO a upgrade in lifters would be very helpful in longevity. It may not be needed but a lifter with the edm hole at the base is a good move. Not an needed one, but a good one.

Also, @ 408 cubic inches, it is hard to get enough cylinder head up top. Even if it is just a cruiser that you want to “Be able” to get up and go to kick a little ***. The OE iron heads fully ported fall short of an Edelbrock Head which is barely enough when fully ported for 400+ cubes. So, ether fully port a set of Edelbrock Head or live with leaving A LOT on the table.

On intakes, the LD-340 is OK, a ported Edelbrock RPM is best but very expensive. A 750 cfm on the street and around town should be just fine.
Overkill, no way.

My only notation on a cam is, choose the duration in which you expect to operate in, cruise down the road with. And get as much lift as you can from the cam and/or the cam and rocker ratio to take advantage of the cylinder heads ability to move air. If your cylinder head moves air well to .600 lift, try and get the valve up there. It isn’t necessary to lift beyond it or get exactly that much lift. But if it is available for use, why not reach out and grab it?

Other cam manufacturers are out there and they make nice cams as well. The basic guidelines above should be of use to you in your search. I have found what makes one better than another could have a short coming against another cam or the one being compare to.

Cam opinions are like farts, some stink more than others and no one has the magic cam. The cam has to fit and suite your build for you. You can do a good job on your own. Read the cam manufacturers sites on cams (all of them) and then go for it.

 

[zsn0w]

@rumblefish360 Thanks for all the info, that's exactly the kind of advice I was looking for. The car it will be going into is a 1974 roadrunner. Right now it's just a stock 318 with a floor mounted 3 speed. Eventually, I'll be swapping in an OD 4 speed once the engine is all good to go and I have some time to save up some money after all the cash I'll be dropping on the engine build haha. I'm not sure exactly what the rear gears are, but I believe it is stock, so should be very mild (it's got an 8 1/4 rear in it which I believe is original to the car, but I have yet to get into it to verify). I want the car to be able to drive on the highway, so I don't want crazy gearing or anything (which is why I think I'll end up going with the OD A833). This is going to be a driver first and foremost and I don't plan on babying it (got another project for that). It's going to be pretty close to stock weight, although with aluminum heads I guess it will be slightly lighter but I doubt that would have much of an effect given the weight of the cars body. I'll have to check the size of the tires I have on it when I get home, as I haven't changed them since I bought the car and getting new wheels and tires is way down the list. Seems like the consensus is to use the higher quality valvetrain components that are recommended with the cam. So, If I bought some Edelbrock 60779 heads from Hughes, would the springs and and everything included be good to work with Hughes rockers, lifters, and pushrods, or should I go for heads without any springs, retainers, etc.? I've taken a look at compcams quite a bit, as well, just haven't narrowed it down as much as I have with the Hughes offerings. Thanks again for all the help.

 

[1967coronet440]

That 8 1/4 has to go, need at least a 8 3/4 or better yet a Dana. I’ll leave the engine and trans to rumble

 

[zsn0w]

That 8 1/4 has to go, need at least a 8 3/4 or better yet a Dana. I’ll leave the engine and trans to rumble

Thanks for the advice. That's definitely on the list of things to do down the line. I'm probably going to keep a milder ratio when I swap it, though, as I want to be able to drive it at highway speeds when necessary. A 9 1/4 should be a direct fit if it's taken from a 73-74 big block b-body, right?

 

[rumblefish360]

@rumblefish360 Thanks for all the info, that's exactly the kind of advice I was looking for. The car it will be going into is a 1974 roadrunner. Right now it's just a stock 318 with a floor mounted 3 speed. Eventually, I'll be swapping in an OD 4 speed

Your welcome. A 3spd MANUAL to a 4SPD MANUAL? The cars close approx. weight is on the reggie.

I'm not sure exactly what the rear gears are, but I believe it is stock, so should be very mild (it's got an 8 1/4 rear in it which I believe is original to the car, but I have yet to get into it to verify). I want the car to be able to drive on the highway, so I don't want crazy gearing or anything (which is why I think I'll end up going with the OD A833).

Stock gears still leave a wide variance. They could be as low as 2.76 to a high of 3.23 or 3.55. I'm not sure what was offered then. To figure out the final drive ratio with your OD trans, take the transmissions over drive ratio, in a MoPar's case, it is often .69 with automatic transmissions and multiply it by the axle ratio. An example would be;
4.10 X .69 = 2.829 or rounded, 2.83 There are other factors to this final drive feel starting with tire size and converter slippage that may alter it up or down some. This final drive ratio should work with your cam choice.

As far as I know, the 9-1/4 came with a best of 3.55's. Do the math! (2.449)
Get new gears if need be.

It's going to be pretty close to stock weight, although with aluminum heads I guess it will be slightly lighter but I doubt that would have much of an effect given the weight of the cars body. I'll have to check the size of the tires I have on it when I get home,

Do so check actual weight and tire size. Any weight removed is a help and it is more than just overall weight. It is also where it is removed and how it effects the weight balance. Not so much of a huge importance on a street car vs a drag car.

Heads, approx. 50 lbs. savings.
Intake, approx. 25lbs.savings.
Exhaust manifolds to header savings. 25 lbs. or so.
This so far has equaled a tenth in the 1/4mile.
Not so important?

Seems like the consensus is to use the higher quality valvetrain components that are recommended with the cam. So, If I bought some Edelbrock 60779 heads from Hughes, would the springs and and everything included be good to work with Hughes rockers, lifters, and pushrods, or should I go for heads without any springs, retainers, etc.? I've taken a look at compcams quite a bit, as well, just haven't narrowed it down as much as I have with the Hughes offerings. Thanks again for all the help.

You don't have to purchase the heads from Hughes but there valve train system is nice. I have one myself. I'd purchase the heads, cam, valve train as a group or system at once or at least get part numbers to keep on hand and order as monies allow. Hughes has recomended parts to use with they're equipment. If you purchase a Hughes cam, (Or a Comp Cam, or a Lunati cam... but double check how they fit in the head. hughes did this work already for you.)
Also get the rest of the package to go with it. Lifters, springs, retainers and locks. It will all work together.

IF I do this again, and OH I WILL! I'd start with hughes engines Edelbrock heads with the pushrod holes closed up and moved over with no porting work done. I'll tell them "I got this!" I will take my heads to a local porter. My local guy does really REALLY nice work. He went to Mondello's school of head porting. he works at his family biz building racing engines. Super Excellent work. Find a local guy to you with the same/similar credentials or look for known porters here. There are a few mentioned here on the site worthy of your time and money.

The heads need not be "Race Ported" but fully touched.

Thanks for the advice. That's definitely on the list of things to do down the line. I'm probably going to keep a milder ratio when I swap it, though, as I want to be able to drive it at highway speeds when necessary. A 9 1/4 should be a direct fit if it's taken from a 73-74 big block b-body, right?

I do think that is correct. Measure twice, cut once comes to mind. It's hard to keep these things (specs) in my head.

 

[1967coronet440]

Not sure on the measurements for the Dana’s, plenty of charts floating around you can reference. Also strange, and moser offer some really nice aftermarket options if it’s in the budget.

 

[zsn0w]

I'll be figuring out the weight and ratios tonight for my car so I can provide some more concrete numbers to base this off of. Also, it is a 3 speed manual and I'll be swapping in a 4 speed manual later, forgot to write manual in my last post, sorry. One more question before that, though. The way I understand camshaft selection is that I want a duration that gives me power in the low-mid range for a street motor, and I want to get as much possible lift out of that as I can to increase power. Essentially, duration will move the curve to the right as it increases, and lift will move it up? Is this correct (in a very simplified way, of course)? I'm pretty set on a Hughes cam and valvetrain at this point, I think, as the Comp offerings just aren't aligning as well with what I believe to be a good fit for my build based off of my understanding of camshafts. Apologies for asking so many basic questions, most of my experience (sorry for this haha) is in turbocharged 4 cylinders with overhead camshafts where the cam choices are very limited and not really that big of a factor compared to other modifications.

 

[rumblefish360]

View attachment 648918 Not sure on the measurements for the Dana’s, plenty of charts floating around you can reference. Also strange, and moser offer some really nice aftermarket options if it’s in the budget.

Oooo boy! A Strange 60?
Seeeeex y!
Tell ya about that bad boy! Nice!

 

[rumblefish360]

I'll be figuring out the weight and ratios tonight for my car so I can provide some more concrete numbers to base this off of. Also, it is a 3 speed manual and I'll be swapping in a 4 speed manual later, forgot to write manual in my last post, sorry.

No worries. I love to row my own boat.
Manuals can also use and tolerate more cam duration.

One more question before that, though. The way I understand camshaft selection is that I want a duration that gives me power in the low-mid range for a street motor, and I want to get as much possible lift out of that as I can to increase power. Essentially, duration will move the curve to the right as it increases, and lift will move it up? Is this correct (in a very simplified way, of course)?

Yes
More duration
(bigger numbers or longer duration)
will move the power lines up the rpm scale.
(To the right)
The cylinder head will limit how far up (vertical)
the power scale it goes.

I'm pretty set on a Hughes cam and valvetrain at this point, I think, as the Comp offerings just aren't aligning as well with what I believe to be a good fit for my build based off of my understanding of camshafts.

Well, that is half the battle. You have to feel good about your choice. The best part is looking around on as many manufacturers sites to read about there thoughts and theories on the subject of cams. I have read a lot and all I can say is that if your looking for every last once of power, there is no one magic cam. But many can perform really well and there all close in specs.

There are guys that can dissect a cam, logically say this one is better, but that doesn’t mean it will perform better, call up there own custom spec. They/You can slice, dice, chop, shake, stir rattle and roll a lot of chatter about cams but sometimes, even the best miss.

Learn what you can. Read what you can. Search and find videos and builds with graphs and when all that is done, make a best guess effort. If you “Get” the talk about cams, you can probably make a very good choice.

Apologies for asking so many basic questions, most of my experience (sorry for this haha) is in turbocharged 4 cylinders with overhead camshafts where the cam choices are very limited and not really that big of a factor compared to other modifications.

No worries, I get it. Even more so when the engine is pressurized. What was it you were working on last or most familiar with?

 

[rumblefish360]

Again, cam size is dependent on a few factors.
Depending on your gear ratio and the final drive ratio with the intended OD trans, you will have to get with an on line calculator that can show you your engines rpm at what ever you input in as your cruising speed (on the Hwy.) with the exact tire size, (metric or inches) and the intended OD ratio and the intended gear ratio.

If this cruise speed comes in at, oh let’s say, 2,200-ish rpm’s, your cam choice is going to be a smaller cam, like the 1st one you listed.

If it is up higher around 2600-ish rpm’s, the second cam would be better.

You want the cruise rpm to be a few hundred rpm into the cams listed power band. Most companies will list the cams intended power band. The increased cubes lowers the power band a little bit.

 

[rumblefish360]

Again, cam size is dependent on a few factors.
Depending on your gear ratio and the final drive ratio with the intended OD trans, you will have to get with an on line calculator that can show you your engines rpm at what ever you input in as your cruising speed (on the Hwy.) with the exact tire size, (metric or inches) and the intended OD ratio and the intended gear ratio.

If this cruise speed comes in at, oh let’s say, 2,200-ish rpm’s, your cam choice is going to be a smaller cam, like the 1st one you listed.

If it is up higher around 2600-ish rpm’s, the second cam would be better.

You want the cruise rpm to be a few hundred rpm into the cams listed power band. Most companies will list the cams intended power band. The increased cubes lowers the power band a little bit.

 

[zsn0w]

Thanks again for all the info. I guess one of the advantages of this being a longer term, lower budget engine build is that I have plenty of time to research and decide on the heads as I build the bottom end.

No worries, I get it. Even more so when the engine is pressurized. What was it you were working on last or most familiar with?

The other engine I'm working on and where most of my experience and knowledge applies to is a 4G63 turbo from a 93 Eagle Talon. It's going into a 1974 Dodge Colt, so it's much more of a full project car than this engine build. Probably going to end up around 300 HP in the configuration I'm aiming for, so not too bad for a 2200 pound car. When I bought the roadrunner, I was actually intending for it to be a regular driver that I'd keep the stock drivetrain in, but the 318 just isn't enough "Oomph" for me, and the car really needs a once-over anyway. Wanted to get a 360 to drop in, then figured if I'm going to be rebuilding the whole thing anyway, why not stroke it and get all that extra torque?
Going to be figuring out the specs on my car tonight, didn't get a chance to last night as I had to catch up on some other things and all my paperwork for the RR is actually at my parents house as I just recently moved.

 

[rumblefish360]

Well then! Congrats on the new digs!

 

[zsn0w]

Well then! Congrats on the new digs!

Thank you! Been there about a week, and it is great to finally have my own usable garage space. I've been lucky enough that while I lived in places without garages my parents let me do a lot of wrenching in their garage and driveway, but it's great not to worry about staining someone else's concrete anymore haha.

 

[Hemirunner]

You might ask Hemmirunner, he did a stroker sb not to long ago. I'm sure he could give you some pointers. BTW do not skimp on the valve train components!

We only made 630hp on pump gas with that one...

 

[zsn0w]

We only made 630hp on pump gas with that one...

Wow, that's awesome. What components did you use? Any tips on common mistakes or problems I'll run into? Sounds like a really impressive build.

 

[Hemirunner]

Wow, that's awesome. What components did you use? Any tips on common mistakes or problems I'll run into? Sounds like a really impressive build.

It was a fairly high end build. We used an R3 block, 440 inches, Callies crank, Molnar rods, Diamond Pistons, Edelbrock Victor heads, and a hydraulic roller cam. Nothing like what you’re building here. The other guys have you on the right path, carry on.