225 slant 6 or 360 v8

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bigcasey123

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Okay guys so i have a 1969 dodge dart. It has the stock 225 /6 in it now with a 2bbl intake and carb and electronic ignition. I would like more power. i would like this car to be close to getting in the 14s (or faster).
My question is would you rather put a 4bbl 500cfm carb with a big cam and headers and oversized valves ported head and 10:1 cr. or build a mild 360 magnum with magnum eq heads and a mild cam. now i am already in the process of buying a 3.23 8 3/4 rear end. But if a get a v8 i will have to buy the engine along with all of its parts, a new k member, a new radiator, motor mounts, a 727 trans, plus a new distributer and all the little stuff. now i know that either route is expensive but what would you guys rather do? a 250-300hp slant or a 300-400hp 360 but much more pricey?
 
V8 without a doubt. A stock 360 magnum can get you in the 14s in a good chassis.
 
its really up to your personal preference
powerful 360s are easy to be made and there are a ton of clear recipes around...many of them right here on the board

on the other hand, if you want to stand out, there are a lot of powerful /6s out there aswell BUT they require a bit more work

as much as I love my V8 I must admit, a blown slantie stands out in the crowd a lot more then a 360 does
and...you wont have anyone bothering you with silly "is that a 340" questions



so, option 1, quick and easy, drop a 360 in there
option 2, completely rebuilt that /6 for power, turbocharge it or whatever and have something that stands out
 
I'll say a stock 360 mag will get ya into the 13's with highway gears. Schumacher makes adapting motor mounts for 150.00 bucks, no need to change the K frame. New radiator, tranny, exhaust, motor mounts. Then, whatever you decide for the motor. Shoot, a stock 318 mag will get ya 14's with ease.
 
everyone is right. my take, the 360 have better potential for more power, but the common way to go. yes the slant will be different and stand out if that is what you want. all slants are woreout and need rebuild. a magnum might be something to read up on here too. I enjoy my old slants just tooling down the road, I have other cars though that go faster! ha
the is a NA toad around here that runs in the 10'a in the quarter. just purpose built engine with lots of $$ thrown at it, but so cool!
 
thanks for all the input. i found a guy whos selling his slant for a grand. it has just about 300 crank hp so i think that will be good for me. its overbored, cammed, 10:1 cr, 4bbl etc. idk what the times would be but im also putting in an 8 3/4 with 3.23s so i should hopefully be around 14s or better. any thoughts
 
Probably doesn't make 300 HP, very doubtfull it will run 14s either. Why's he selling? If it's to swap to a v8, then there's your answer
 
Forget about the slanty
Power is addictive. The slanty will never be enough. Going from 140 to 200 to 230 to 250, is taking forever and costing way too much. Better to install 250 right at the start; and that takes a V8. Now you have potential to go 300 to 400 relatively cheap. And a lot of guys are happy in the mid to high 300s with 3500 pound cars. By 400 to 450 there's not much point in building more.Except for bragging rights.
But I gotta ask; why do you want to go 14s ?
A slanty can perform pretty good in first gear if you give it what it needs;namely gears and a higher stall. It won't go 14s or 15s or maybe not even 16s, but first gear can still be a ton of fun.
Ima thinking 3.91s and 2800 to start. Yes you will need a SureGrip. 3.23s are not nearly enough for a slanty, unless you have a 2.74 lowgear in that 904, then 3.55s will get you a good start.
If you need the car for hi-way useage, for sure ditch the slanty, build a hi-torque 360 and then the 3.23s may work. With good heads the 360 can sneak you into the13s easy. Maybe even into the twelves..... Mine went there with a 223@.050 and 3.55s(stick-car).
So again, why 14s?
 
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That slant will need some SERIOUS head work to be at 300 HP, and I seriously question that is there. Is there a for-real dyno sheet with it or have you seen it run up the track? And if it is, it will likely be pretty peaky and not likely a good drive-around engine. All that changes if it were turbo'd but at 10:1 CR it won't be. (Some of the leading edge rally cars are turbo'd hard with 10:1 CR but that is not this....) I would be very suspicious of the seller at this point unless..... there is one guy in the Waynesboro PA area who could do an engine like this; HE I would listen to. What part of PA are you in?

All the above is well said.... despite my strong liking of /6's (I have owned 4), if 14's is what you want, the 318/340/360 is the route to go. I don't often say that....
 
Your post is quite helpful. I am new to this group. I have a 65 dart gt does the motor monuts work for this year as well? I am really trying to o the cheapest and easiest way to hp.
 
Tyson said:
Your post is quite helpful. I am new to this group. I have a 65 dart gt does the motor monuts work for this year as well? I am really trying to o the cheapest and easiest way to hp.
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Power potential is pretty much determined by head flow. Stock 273/318 heads are good for about 300hp, 1.88 valved 340/360 heads are good for about 375 hp and 2.02 340 and magnum heads are good for 400 hp and EQ's and edlebrock 450 hp.

So the best bang for the dollar is to get a good running 5.9 magnum just 4 bbl and headers is said to make 320 hp and add a cam for another 30 - 80 hp depending on how aggressive your willing to go.

I'd go with the largest cam you can get away with stock stall probably around 215-220 duration.
 
For non-track use it's hard to beat the low end torque that the larger displacement the 318/360s provide.
 
bigcasey123 said:
thanks for all the input. i found a guy whos selling his slant for a grand. it has just about 300 crank hp so i think that will be good for me. its overbored, cammed, 10:1 cr, 4bbl etc. idk what the times would be but im also putting in an 8 3/4 with 3.23s so i should hopefully be around 14s or better. any thoughts
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If it has a "true 300 hp", and your putting it in a A-body with 3.23 gears, you will blow right by 14's.
 
Be aware that when stuffing a 318/340/360 into an early A body, then the engine compartment gets really tight in a hurry. So do a bunch of reading up on fitting fans and radiators, and the exhaust systems you can stuff in there with a V8, before making the plunge. It is all doable; just be mentally prepared for it to be a bit of work.
 
Tyson said:
Your post is quite helpful. I am new to this group. I have a 65 dart gt does the motor monuts work for this year as well? I am really trying to o the cheapest and easiest way to hp.
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Those two words should never be in the same sentence, especialy in a 65; there is no easy, and there is no cheap.
The cheapest I have done it is by dropping in a complete running V8 with it's automatic and fenderwell headers. Even a 2bbl will make surprising performance through those headers, in a lightweight 65.
Additionally all you need for this is the front engine mounts. This is about the most basic swap there is.Even a tired junkyard teener will about nearly double your performance, over a tired 225.With 3.23s it should keep you happy for quite some time. Add a 4bbl and 3.55s, and you're all set.
I ran a 340 with teener 2bbl topend from the decks up,and the teener cam, in 65 long-roof with 2.76s. With skinny vintage 1969 tires,It was a blast! A real hoot! First gear was good to well over 60mph!

EDIT
OOps, 1969.............. almost same story;but make it a 360 to compensate for the slightly heavier bodystyle. And scratch the fenderwells, for any old header. If you intend to run the 7.25, make sure to put a Suregrip in it, or run some bigger rubber, cuz it may not last long being peg-legged with skinny tires.
 
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It has a bunch of head work done to it. Oversized valves 3 angle valve job and a port job. the builder said it beat stock 4.7l mustang gts (275hp) in the 1/8th mile with 3.73s. i beleive he said it ran in the 8s? but it is very built for a slant and he said he never dynoed it but it beats stock mustangs all day.
 
8.00 is plenty quick
8.999 not so much
The point is she will be maxed out, with no room for more, so if it ain't fast enough, your next option is a V8. Again. So you might as well go V8 right from the get-go.
Oh yeah, what gears was the little slanty running again? hi-4s/low-5s?
A V8 will get into the 8s pretty easily and still have great street manners, and if built right will get pretty good fuel economy too.And it might do it at the top of second with like 3.73s or maybe even 3.55s.
The 69 is too heavy for a slanty.
For about the same money, you should be able to get a good running 360 in there, and with nothing more than a 4bbl and a 340 cam,go 14s easy.
 
nm9stheham said:
Be aware that when stuffing a 318/340/360 into an early A body, then the engine compartment gets really tight in a hurry. So do a bunch of reading up on fitting fans and radiators, and the exhaust systems you can stuff in there with a V8, before making the plunge. It is all doable; just be mentally prepared for it to be a bit of work.
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Will you have to make any changes to the compartment to make it fit? Or you just saying that it will be a tight working space?
 
Ok, 3.73s
So now the picture is starting to come together
Given the 300hp, and assuming a 3150#raceweight this makes 300/3150 = a P/W of .095. Bulletin #40 says this,with race suspension and an auto should go about 12.5/12.6 in the qtr and about 101mph. Dividing the qtr ET by 1.57( the accepted conversion factor), we get 7.99 as an approximate 1/8M ET . Adding up to .5 for suspension problems you could indeed have a 300 hp slanty.
So say 8.25 seconds. This is about high 80s mph. With 3.73s and 27" tires, this makes about 6000rpm, at the top of second gear.(Hitting third, will drag the Rs down somewhere near 4200)
Now, here's what you have to know; To do this, that poor slanty, in addition to the already mentioned headwork,and the typical bolt-ons,will need a heck of a cam, and a heck of a TC. These heck-ofs are not real street-friendly.

IMO, you would be far better off starting off with an additional 100 to 135 SBM cubic inches. Then you can run a much more street-friendly cam and TC, and rear-gears, and still go 8s. A 225ish* cam and a 2800 should get you there, perhaps even with 3.55s with the right headwork.
The 3.55 gears with a 2800; I can tell you from years of experience with all kinds of gears,are a lot of street-fun,even with a 360-2bbl cam(252*), and are still fun ( but won't hit 8s)with a stock teener(240*) cam. Like said earlier, with a 2.74 low tranny,3.55s really shine.
Whatever you decide, all the best to you.
 
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Thanks for your opinion. you are right though... it is less streetable. but the PO did use it as a daily driver and i live 1.5 miles from school so its not that bad. now what your saying is right that it a mild v8 will have better street manners. but rn i found a really good deal so i think im gonna take it. the cam is an erson cam 230@.050 108lsa 510 lift... so way more aggressive than stock no question. and the PO did tell me he ran very low 14s, but my car is lighter so i should be in the high 13s depending on my gear. And right now the biggest reason im going with the slant is because i just think its cool and different to have a hot 6 cylinder
 
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