360 or 408 streetmotor

[J780]

Hi everyone I am new here.
I have a 73 360 with KB107 pistons: compression is 9.8-1, w2 econo heads
pocket ported for a mopar 284-.528 cam 112 Lcl installed at 4* advanced,
M-1 single plane intake. The car has a built 727 with a 3,000 stall convertor
and manual shift valve body. The exhaust is TTI step headers with 3" pipes
with x pipe and dynomax ultra flow mufflers.
What I would like everyone's opinion on, would this
combo with 3.91 gears 29" tall 13" wide Mt tires in a 2900 pound car
be very street able or would I be better off moving 90% of the combo
to a stroker small block. I need enough horsepower and torque
to run 11:70's at about 300' above sea level on a good day. I plan on bracket racing twice a month and driving the car on the other weekends with in
50 miles of my home.

[dust]

Originally Posted by J780

Hi everyone I am new here.
I have a 73 360 with KB107 pistons: compression is 9.8-1, w2 econo heads
pocket ported for a mopar 284-.528 cam 112 Lcl installed at 4* advanced,
M-1 single plane intake. The car has a built 727 with a 3,000 stall convertor
and manual shift valve body. The exhaust is TTI step headers with 3" pipes
with x pipe and dynomax ultra flow mufflers.
What I would like everyone's opinion on, would this
combo with 3.91 gears 29" tall 13" wide Mt tires in a 2900 pound car
be very street able or would I be better off moving 90% of the combo
to a stroker small block. I need enough horsepower and torque
to run 11:70's at about 300' above sea level on a good day. I plan on bracket racing twice a month and driving the car on the other weekends with in
50 miles of my home.

I think the extra cubes would better take advantage of the 3" exhaust and the W2 heads. But for a 2900 lbs car, the additional stroker torque does not sound necessary.

[J780]

Thanks for the reply, since i have not ran the car yet I was not
sure it would make the 11:70. It seems fairly streetable now. But
I thought the more cubes would calm it down a litte for the street
driving.
aj780

[dwc43]

Your better off with the 360 you have now. IT will make much more power and the stroker will be limited somewhat. With the heads you got, you can make enough hp to get what you want.And the strokers extra torque will create traction issues in such a light car.

[J780]

You guys are great thanks for the reply dwc43.

[dwc43]

Welcome,anytime.

[TK]

Originally Posted by dwc43

Your better off with the 360 you have now. IT will make much more power and the stroker will be limited somewhat. With the heads you got, you can make enough hp to get what you want.And the strokers extra torque will create traction issues in such a light car.

I am crying BS.

First off, if you want a 408, build a 408, there is nothing wrong with them! Sheesh! Better off, can we keep one wheel on the pavement here dwc?

The stroker will NOT be limited, at all, in fact, less limited than the 360. Why? More cubes, simple as that. Dust was right, those w2's will work nice with the extra cubes, REAL NICE! Yes, you can make the power you want from the 360, but, here is where things get different.
You will be able to get more DRIVABLE power from the 408, with the same components, because the 408 will have a SMOOTHER power curve, with the same components. A SMOOTHER power curve, will be easier to hook up, more predictable, in other words.

(Example, a 2900 pound car, with a 273, runs 11.50's...............)

You will need, mega solid/roller cam, cool heads, 11-1, 4000 stall, and 7800RPM, lets say.............

(2900 pound car with a 440, runs 11.50's)

Stock mildly ported heads, fairly mild hydraulic cam, hell, you could probably keep your power brakes, and 10-1 pump gas, shifting at, say, 5600, with a 3000 stall.

You could drive the 440 around, in rush hour traffic, idle through the McDonalds drivethrue with your kids, and pull a small camper trailer, if you had 4:10 gears.

These were just examples, BTW, but I think you get my point.

[Kevin Garceau]

I would go with more cubes as well. I would NOT put a thermoquad on it either for that matter... sorry DW had to throw that in there.

The heads will be fine, and can always be upgraded later. Easier to sell a set of heads and upgrade than it is to redo a whole bottome end short block......

I also agree with the more cubes you can put less radical parts in it. Which will make it more streetable. The only place may be an issue is cooling. But since you will run less compression on the 408 to make same power it shouldnt matter.

[rumblefish360]

Originally Posted by dodgetruckboy

I am crying BS.

You ain't kidding brother! You ain't kidding.
Traction problems are a right foot problem for starters, suspension second in a street bound car. Your part time street car that will see more track have better had some looking into for straight line performance reguardless of the weight and engine power combo. In the street, a well looked after set up should have no problems driving around in a spirted manor.

How one makes more power from a 360 vs. a 408 and has it better for the street is beyond me. Equal type builds mind you.
Thye only way a stroker will limit you in the street is in your wallet during build up for the extra money in non-stock parts.

Listening to DW will put you in last place losers club.

Your right on a larger engine theroy, being it will act calmer. Larger engines make big cams act smaller. It'll also peak in HP earlier due to increased stroke, still produce equal HP numbers next to the 360 or better. The W-2 heads will work just fine with the extra displacement.
Also listen to Kevin Garceau. He has a grip on things.

[kamstra]

Definately a 408. My buddy had a 408 and a spare 360. Currently, he has the 360 in an early Barracuda. The 408 is was quicker 10.80's and has the same street manner as the 360 running mid 11's. I also have a 408 in my 70 Barracuda. Had I build the engine as a 360 (same heads, cam etc) it would not run as quick nor have the street manners.

[1973Swinger]

I agree also, 408 for sure, just make sure to use a forged crank, not the el-cheapo cast piece. My buddy built a 383 stroker for his chevy truck and learned his lesson about cast storker cranks the hard way when it snapped and sent rods through the oil pan and block.

Oh, if you ever want to sell those heads, let me know, Ill be starting the build on my 408 before all that long and will be using W2s on it. Good Luck with the build!

[dwc43]

Originally Posted by rumblefish360

Listening to DW will put you in last place losers club.

Your right on a larger engine theroy, being it will act calmer. Larger engines make big cams act smaller. It'll also peak in HP earlier due to increased stroke, still produce equal HP numbers next to the 360 or better. The W-2 heads will work just fine with the extra displacement.
Also listen to Kevin Garceau. He has a grip on things.

That's B.S. The 360 properly built with those W2 race heads will out preform the stroker in the long run, hands down. Like you said, your stroker will peak way too soon compared to the 360 and that's where I out run you.

[sanborn]

I don't think there is a correct answer, just opinions. It all depends on what the owner wants!

I would like to point out a couple of things about W2s. They are an excellent design, and have been since first introduced in 1978. The later revisions just make them better. W2s are a high flow head, have fairly small intake runners(compared to GMs) and depend on velocity to fill the chamber. They react well to higher lifts(around .590" for stock W2s) and work really well with high lifts when properly worked in the valve pockets(around .640"). So if you are thinking about using them---think higher lifts and a roller on the street.

The small runners/high velocity means even 340 engines are responsive on the street. And a properly worked dual plane intake would work great up to about 6500RPM. If you want to go further than that, a single plane is necessary. And a single plane is not as streetable.

Now to the cubic inch question. A set of mildly worked W2s will feed an engine up to about 360", it takes a fully worked set to feed an engine up to about 390". Engines larger than that really lose peak HP RPM quickly.

So the decision is still up to you. But, take a word of advice, if you bolt on a set of even mildly worked W2s, spend some money on the crank and rods.

[BlackAce]

Here is a nice right up about a 408 Stroker.

http://www.truckinweb.com/brandpages...a_408_stroker/

[youstacood]

you better put huge gears behind that 360 to stay with that 408...i can see it from both angles...but more displacement will run stronger. no overreving the engine to make the power. that 408 will be pretty sweet. in fact, my step-dad is getting this job soon as pipe bender at a custom fab shop, and he is going to do a project like i wanted to do back in the day...a v8 in a daytona. i told him to take my '69 440 and 906's and forged crank, but he just wanted to stick with the 360 in his work van...that little car will haul nuts!!! cant wait, i want to drive it someday too. (i still think i t will be sweeter with a 440 in it...)

408 360

read the last post, go to article..
how much money do you have to dump into the 360 to make 544hp and 565 lb/ft of tq? LOTS more than jsut a stroker kit...

[pishta]

360 vs. 408. Hmmm, ask a chevy guy what he would rather race, a 350 or a 400 small block. Most would say the 350 hands down, yet they still build their 383's. Dont know, how much more is a 408 in greenbacks? Could that extra money be used on an upgraded set of heads or a neato carb for that 360 to make it competitive? Ill sit back and watch this one... Dont ask me, I own a stroked 400 myself in a 2900 lb car...

[rumblefish360]

Originally Posted by dwc43

That's B.S. The 360 properly built with those W2 race heads will out preform the stroker in the long run, hands down. Like you said, your stroker will peak way too soon compared to the 360 and that's where I out run you.

But you'll need more gear to reach the goal due to the increased torque output. Thus a harder working engine that creates more heat to keep up.
Peak way to soon? Come on now, I'm laffin at you with that response. The stroker will use a lower (Numeric) gear and still out do you.

Go back and re-read the post silly.

[dust]

Originally Posted by kamstra

Definately a 408. My buddy had a 408 and a spare 360. Currently, he has the 360 in an early Barracuda. The 408 is was quicker 10.80's and has the same street manner as the 360 running mid 11's. I also have a 408 in my 70 Barracuda. Had I build the engine as a 360 (same heads, cam etc) it would not run as quick nor have the street manners.

Post the video!

Kamstra posted in a similar thread I made a couple of years ago, helped me decide in favor of the 408.

I think one of the main deciding factors in this decision would be the answer to this question:

How much money are you looking to spend with this build?

[George G. Leverette]

Both of the engines will make the limit of approximately 435 HP max if you want the engine to live. The larger bore engine will have more torque down low and quit revving, while the smalle bore engine will have a higher rev limit. With the 30-40 year old engines a cast crank, Eagle rods and KB stroker pistons will produce approximately 400 Hp. If more horse power is needed then an after market block such as the R-3 block should be used to get to the 650 HP mark. Other after market small blocks are good to 800 Hp.

[J780]

Reading all the replys it looks like the stroker seems to win.
I think George hit one of my concerns, with the small rod ratio
with the stroker it will probably put a lot of side load into the
thrust side of the cylinder walls. Being a part time street motor I was
not sure the motor with a partial block fill will still run cool. The
R3 block ($2500 plus alot of machining) was not what I wanted
to realy do. I was thinking the botom end of the block, stroker
kit and addtional machine work would probably cost me
around $4,000, using the early 360 block. My other option
might be to split the difference and run a 3.79 stroke rather
then the 4" stroke. The sonic test on the 360 block would
leave me go out to 4.06, which would be .020 more
then i am at now at .040. If my block is still round at .040 and
the new piston clearance checked I would not take it out the extra .020.
The cubes would be 388 and the rod ratio would be better at 1.6.
I also just found out the bracket brake here is 12:00 not 11:70,
so I would not need as much horse power/torque. Thanks for everyones
inputs. Keep the inputs coming.

[TK]

Originally Posted by dwc43

That's B.S. The 360 properly built with those W2 race heads will out preform the stroker in the long run, hands down. Like you said, your stroker will peak way too soon compared to the 360 and that's where I out run you.

You sounded just like a Chevy guy just now................ "I'll, I'll, I'll........outrev you! That theory DOES work, but wouldn't be as street friendly, as mentioned before.

Not arguing that a 360 isn't capable, or reliable, like you think, just saying to make the same power as the 408, it will not be as street friendly, that's all.
The 408 will make the same power, and be more streetable, there is no argiung that. Well, there is, but no one will listen.

with the stroker it will probably put a lot of side load into the
thrust side of the cylinder walls.

It will, but with a good set of forged pistons, and it being a weekend driver, you wil be pulling it out to freshen it up long before problems arise.
(Not any worse than a small block chev............)

[kamstra]

Originally Posted by dust

Post the video!

Kamstra posted in a similar thread I made a couple of years ago, helped me decide in favor of the 408.

I think one of the main deciding factors in this decision would be the answer to this question:

How much money are you looking to spend with this build?

Hey DUST!!! I hope you got your ride altogether and you are enjoying it. Here is the video in an early cold spring day. It is just a quick rev to wake up the neighbors LOL

http://208.63.61.10/imagebank/Rob/70cuda/spring-rev.AVI
The 408 moves incredibly well for the mild build. It is a formidable street machine. Right now, it is also a very easy to drive and strong torque engine. Perfect for it's purpose for cruising with the family (and having a little fun)

There are many 408 stroker builds running 10's without any block fill and using cast cranks. My neighbor down the street has one.

You WILL have a car with better street manner with a 408 versus a 360. Or you will have more power with a similar combo 408 versus a 360.

It ony cost me about $600 more to do the 408 versus a 360. I internally balanced the engine which added to the cost but would be about the same had I internally balanced a 360.

Rob

Dust, Sorry I do not post here to often. I would love to see how your ride is doing

[J780]

No, ch/// stuff here, I would like to keep the revs down.
I use to run a 383 and it was no way streetable, plus was
a buzz saw rpm wise. So do you think the 360 casting
will hold the thrust load with out major problems. Understand
I am not against building the 408/410. I just want to make
sure it will last for the money put into it,
with out cracking the cylinder walls down the road.
Thanks for the input.
j780

[J780]

kamstra that sounds great, how long have you been runing
the 408 now. What kind of heads and exhaust?

[J780]

Dodgetruck boy when I said 383 I meant Dodge the ch/// guys
stoled our ci numbers I forgot.

[TK]

Alright, I am going to throw something else into the mix. For me, there is one choice between the 360, and 408........................

390! (3.94x4")
Why? The 3.31 engines have smaller main bearings, which means less friction/heat. It is proven that the 360 over did the bearing surface on the mains, for the higher RPM ranges. I know, I know, you guys run em all day long, at 7000rpm's............but facts are facts, and facts are, the 360 has more drag.
Smaller bore. I believe a smaller bore, is better for three reasons.
(Less friction)
(Better combustion)
(Better piston life)
The reason fo rthe better piston life, would be............if you have a bigger bore, and a smaller bore, with he SAME clearance, in all reality, the smaller bore will have less clearance. (Less room to rattle) WHich will help with the short rod issue.

Smaller bore should be more eficient, because the fire has less room to travel, which means the flame will easily reach the outside part of the piston. Efficient means power.

BEcause the 18 inch difference between the two strokers is not much, I really think the gain you get from the smaller bearings, and bore, should almost make up for the difference in the inch size.

(And you can show your chevy guys the "318" cast into the side of your block.................)

[J780]

Dtb I do not disagree with your theory, but I would think
the 2.02 intakes nor maybe the w2 heads will flow with
the 3.94 cylinder, but I am no expert. Maybe a 3.97 bore
and the ch// guys would like this 396 ci., 318? Everything
I have read , which could be wrong, the smaller cylinders
like 1.88 to a 1.92. The 1.92 valve might be to big for shrouding
the valve in the cylinder. I know one thing teen motors only
cost a dime because everyone wants the bigger cube motors.
j780

[kamstra]

Originally Posted by J780

kamstra that sounds great, how long have you been runing
the 408 now. What kind of heads and exhaust?

Thank you. I have been running the 408 about 2 years now. There was very little piston choices back then. There is a lot more now.
The Exhaust is TTi step headers with a X pipe and cheap Dynomax Mufflers. I am using Edlebrock Heads and a RPM intake.
I used KB pistons with a quench dome that had to be milled to fit. I was going to use a set of X heads but moved up to the edelbrocks. This then necessitated milling the pistons to approx Zero deck with effecively gave me 9.5 compression. With Aluminum Heads I could take more compression, but it allows me run any gas I desire. (I could almost use kerosene LOL) I would not suggest these pistons unless you plan to use open chamber heads and massage them for appropriate quench. I would build a 10: or 10.5:1 if you wanted more power.


I used the Comp Cams XE 275. (231 at 50) This cam acts very mild in this engine. A bigger solid single pattern cam would build more power in this mill given the better flow of the Edelbrock heads. The only downfall of a solid cam is the occasional adjustment and need for adjustable vavletrain (if you did not have it already)

It was a relatively inexpensive build. Basically the cost of the crank and mallory for balancing.



[img]

[1973Swinger]

Originally Posted by pishta

360 vs. 408. Hmmm, ask a chevy guy what he would rather race, a 350 or a 400 small block. Most would say the 350 hands down, yet they still build their 383's.

Thats not a good comparison in this case. The 400 Chevy was never a big hp engine, it was built in the smog era to give a little boost to some of the "higer performance" applications and was also a truck motor. The 350 has much more plus parts availability and makes for a great start to a Chevy small block build, especially one with 4 bolt mains. The 383s started out as .030 over 350s with a 400 crank before they started making aftermarket stroker cranks. People would have been stroking 360s alot sooner than they did if Mopar had made a smallblock with the longer stroke crank like Chevy did.

[TK]

Not to mention you just cant keep a bottom on a 400 Chev...........