I'm thinking about building a 408 stroker this next summer. Trick is, I don't want a 10,000 rpm screamer. I'm looking to make it a torque monster. This will be a daily driver when done.
The current setup is a stock '97 360 buttoned up to a stock '98 2500 4x4, nv4500, NP241**, and Dana 60s with 4.10 gears finished out with 285/75 16s.
The donor is a '96 360 that is worn out. The only things that I plan on keeping are the block (duh), the oil pan, and possibly valve covers and distributor.
As it stands the only goodies I'm set on are monster EQ heads (or equivalent) and shorty headers, unless I hear a good argument against them.
I am looking for input on preferred stroker kits, intakes, cams, basically everything. Biggest problem I'm having in my research is cams. Just can't seem to wrap my head around all the numbers.
Sooo.... have fun and throw parts out there like it's someone else's money!

 

If you want torque added displacement is the way to go. Since you have until next summer just do a lot of research and read others build threads. Hughes engines comes to my mind when i hear 408 stroker so check them out. There are others to buy from also.

 

Thanks for the input. I've been going through a lot of build threads and it seems they're all either full out power builds, or just refreshing a stock motor. That's what made me decide to make this thread. Any and all input is appreciated.

 

I'd stay the hades away from Hughes.. parts and pieces from time to time, yes, but you don't want to rely on them for nothing if you don't have to...

408's are the engine mother Mopar should have made.. the piston face to stroke ratio is near perfect.. the engine can be built with bigger valves usually reserved for top end 360's, and still maintain the flow velocity that is synonymous with torque..

just like a smaller engine, it's all about the cam profile.. the cam that is OE in a 360 is an extremely docile profile.. a 318 is docile in a 318, but comes to life in a 360 with it's added lift and wider duration- the 18'r flows almost as much air as the 360 due to that cam.. you can drop a 18'r cam in a '60 without issues, by the way, other than needing a bit of a tune..

if you build out a 360 bored .020 over, and add a 4" crank, there is your 408.. it's 406 w/o the boring.. slight machine work on the block to clear journals is required.. other than that, and needing a tune for delivery of fuel, and REQUIRED beefing of t/c's and transmissions, that thing will fart more torque at idle dang near, than a '60 does peak..

build around a sausage cam, or no larger than a 205, and you will murder Hemi's in a towing competition, off the line in a run, or crawling down a trail.. and the nicest thing about it is that your mileage on a DD will increase, as the engine doesn't have to work near as hard to get you rolling or maintaining momentum as your OE 318/360 does.

 

Thanks for the input drewactual. Couple questions if you don't mind.
Why do you suggest staying away from Hughes?
What do you mean by 205 on the cam?

I have no experience with cams, so I'm a little lost. Any engine I've (re)built in the past I just called in and asked for an rv cam. Maybe I just got lucky with those.

 

Hughes has terrible QC, unless they've improved drastically in the last couple of years... If you google around, you'll find stories to support by assertion.. plus, they overestimate their products performance to a huge degree...

the cam profiles are often numbered.. a 201 is a good low end torque cam for a 360.. a 203x is a good middling.. a 205 and 205x is a good performance cam for moderately built engines.. a 210x is a mac-daddy for street/strip built mopar small blocks..

a sausage cam has a profile built for producing tons of torque down low, as in off idle and below 1800rpm.. an R/V cam is similar, but worked more for mid-range than a sausage.. the 201 comes in a little after most r/v cams....

this is about to get tricky...

the r/v, sausage, and even the 201 is too little for a 408 in most cases.. to the point a lot of builders will refer a 201 profile as a low end torque cam (r/v cam) for that displacement and head configuration..

it's ALL about air flow- about volume, or velocity, or both... your 360 stock is lifting 1.92 valves somewhere in the neighborhood of .490 of lift.. the cylinder and bowl draws in air as the syringe (piston) heads south and creates suction (vacuum).. the volume of air shouldn't be restricted, but you'd want to increase or decrease the velocity based on your engines needs-

so, larger valves (2.02) AT OR OFF IDLE allow about the same volume of air in, but at less velocity.. that disallows the engine to rev as quickly as smaller valves, BUT, at some point in the rpm range, the velocity of the air passing through larger valves equals the velocity of air past smaller valves, which means MORE air into the engine, which means more power.. larger valves= more power, but only AFTER a certain RPM range.. smaller valves= higher velocity, which revs quicker which alters the torque range to lower in the RPM range (and actually increases it at that range), BUT, can't hope to match larger valves after a certain rpm range is achieved, so overall smaller valves don't produce the theoretical power of larger ones...

to dial in torque (which creates HP), you adjust the lift of the valve (height it achieves), and/or the duration (how long it is open).. height of lift decreases velocity, duration (expressed in degrees- so, say, it's open 90*'s out of 360*) can or can't increase or decrease velocity based on it's grind numbers.. then, there is overlap, which is when both valves are open (intake and exhaust) which is good for clearing exhaust pulses, but also to equalize pressure across the block and allow the opposing cylinder to cycle with less restriction..

your cam selection is the absolute basis of your build, and the purpose of your rig is chosen as you select a cam.. the heads flow charts are a compliment to the cam.. the intake manifold and exhaust is next.. then, you match your torque converter (if you're running an automatic trans) to the engines output (which is based on the cam/heads flow)... then, you compliment with the transmissions gearing, axle ratio, and then overall alterations (tire height) to nail down the specific target of torque to the ground..

mother mopar, just like father ford and the servant gubberment motors, create platforms of engines/drive trains that perform through a wide array of service.. which your purposes may or may not fit into.. which is why we dial them in to fit out needs.. and why we toy with the dang things..


the 408 is bigger.. because it sucks in more air on the intake stroke, it needs a larger passage, or a longer duration to get the needed air.. because of that, it will treat a 201 similar to the way a 360 treats a sausage or r/v type cam- and basically because the velocity is greatly increased because of filling the larger void...

head over to crane cams and do some reading.. they even have a free cam profile application you can load on your 'puter and see the different flow rates, as well as expected TQ/HP..

 

Thank you very much for that write up. Time to go digging some more now that I understand a little better what I'm looking at. I was playing around with crane cams program some yesterday, but couldn't get it to show any info. I'm guessing operator error after seeing this.

 

glad I could be of some help....

keep in mind- when scrapping down to the mechanical basics of an engine (displacement, cam profile, intended *compression ratio), you have an opportunity to build an engine that does precisely what you want it to do, and has a range exactly where you need it... you may find that 250rwhp and 325#tq is more than adequate for your purpose, and actually faster AND more economic than a bruiser pushing 450rwhp and 6benjis of tq.. reason: the lessor production is in the range you use it- not above it, and not below it..

when I ran my 360, I found I used it in the range of 1800~2400RPMs most often.. I ran it through the only available gear set of the 46rfe, into a 4.56:1 axle ratio, and out to 35" outside diameter tires (which were actually 34 3/4" when new)... I determined my overall gear ratio using those reducers, which are in fact the engines leverage to the ground.

torque converters for the 46rfe don't have a wide amount of selection, but there are a few.. I chose to stick with a OE replacement w/ updated stators.. that left my stall rate in the 1850RPM range.. leaving the stock electronics in place (46rfe transmissions are hard to program) that meant the converter lock (physically connecting the transmission's input shaft to the engines shaft) took place somewhere immediately after 1800rpm- unless I dug into it..

knowing what the platform for final delivery of power was, it is time to figure out what I needed the engine to produce to make best use of that power... remember, my usual range was 18~2400RPM, and I'm rolling a 7k# truck, often with load behind or in it, at mostly highway speeds of 65~75mph... using the 4.56:1 gears to get it rolling, which is in affect 'cheating', I wasn't too worried about off the line torque- as it was adequate.. I was worried about production of torque at the specific range of 18~2400rpm, which would keep the transmission from 'hunting' gears, prolonging it's life, and allowing the engine to sip fuel easily while maintaining a stoichiometric ratio of 14.7:1 air-to-fuel ratio...

If the engine-to-output(drive train) ratio was a good one, I had power at my usual range, and on tap and ready to go just below it, and just above it.. that is good for passing situations, or hauling **** when I wanted to, as well as slowing situations such as merging traffic.. instead of having to nail the throttle to get rolling harder, or letting it drop off just to have to nail it again to resume speed, I could feed the engine enough fuel to do what I needed it to do w/o venturing too far, at any given time, from stoich ratio's...

It sounds like I was building for economy, no?

I wasn't... I was building for the most efficient engine/drive train I could, which meant power where I wanted it.. It was plenty fast, and capable of at least showing well against most trucks around here, but that wasn't my aim.. my aim was to build a rig that would last forever- which, it is still going strong as can be though I don't own it anymore.. the dude who bought it from me is still happy with everything about it.

all that said, I never re-cammed it... I left the OE profile and just used 1.7:1 rockers to alter the ratio of valve events. If I were to have cammed it, though, it would have been a sausage cam w/o doubt, w/ a range of 800~1800RPM..

what I did do, was cheat... I put those gears in the axles which moved my torque range to the range I wanted/needed it.. that is what altering leverage does- it changes the entire equation....

I wrote all of that to simply express this, which is summed up in a sentence: The relationship between power and range can be attacked from either end, be it the overall gear ratio or engine modifications.. the proper way to do it is the way it seems you are, which is at the absolute foundation (cam).. but even if you go that deep, if you don't consider the engines output relationship with the drive line, you're wasting effort and money... I suggest you define precisely what you want from your build, and follow a specific plan instead of 'bolting on' whatever is available and easy... If I could get back 25% of the money and time I've spent bolting crap on, and use it in a blueprinted build, I'd still have enough time and money to pay Vegas an extended visit... <- true story.

A 408 is about as close to perfect ratios so far as piston face to travel that can be had not only from mopar, but many other makes.. that makes it a great basis to work with.. selecting the accompanying parts, and making sure they work FOR and not AGAINST your final product is imperative if you want to 'do it' right.









*don't forget that cam profile has a huge bearing on compression ratio's; there is static compression which is easy to determine using cylinder volume, stroke, and chamber volume, THEN, there is dynamic compression which takes into account cam profile and when the intake valve closes, which may be as far as 60* into the compression stroke, and which by default lessens the compression... an engine with mechanical compression of, say, 11:1, may be reduced to an actual (dynamic) compression of 9:1..

 

Let's see if I can reply this time (3rd times a charm). Yet again, awesome breakdown. You put in words the basic idea I've had for this build, and helped with the focus point too.

My basic target is 2000-3200 rpm range. Reason being, that is my primary driving/ shifting range (2300 in 5th @70 mph, 3000 in 4th). Take off isn't an issue with the gearing I have, and this isn't an extreme off roader (though it does see a lot of time in the hills).

 

if you go with a 408 build, and use those monster EQ heads w/ 2.02 intake and 1.68 exhaust valves, and the range you are aiming for is 2~3.2krpm, you'll be best served with at least a street performance type camshaft, and NOT a whiplash, sausage, or R/V type cam..

those RPM ranges quoted put you firmly in the 'street-able performance' category...

look for one that gives you all the vacuum signal you'll need- or at least -12~14"...

you may want to venture over to bionic dodge and read some threads there.. those guys are more into building and performance than here, which is more inline to 'help me I broke it'..