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Author Topic:   327 in mod car
leapinlizard
Dirt Freak

Total posts: 402
posted December 13, 2004 01:32 PM  
Been debating this for a while now. So far I can't any resaon not to other than might have to use more rear gear to get back the torque loss off the corner or a longer strooke engine.

I can still get 475-500 horse on two barrels using GM 462 heads and make power till 6800.

What's your opinion?


zeroracing
Dirt Forum Champ
Total posts: 1876
posted December 13, 2004 02:10 PM  
hey man,
go for it!! if i had the money to build a good 327 with decent power i would in a heartbeat! easy to hook up off the corner and pull hard down the striaghts.
i would love to have a good 327 that reved quick. you would be suprised how many shows are won on short stoke motors.
good luck
jason

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted December 13, 2004 02:13 PM  
I have often played with that idea too. Especially with the 2 barrel and stock heads. You would have to turn more rpms but you should be able to do that without the intake system choking the motor off like it would a bigger motor. If your rules require stock heads and 2 barrel then if it were built right and you could turn it tight it should work well. But if you are running against aftermarket heads, 4 barrels and large cubic inches then it prob wouldnt be as much of an advantage.

leapinlizard
Dirt Freak

Total posts: 402
posted December 13, 2004 02:44 PM  
Rues are steel heads and two barrels. I havae a already well balanced rotating assembly with machined block. I got it for trade so the money saved there can go into the heads and carb. I have everything else from last year. I need to get the 462 cut down to 55 cc with a zero deck and an .018 gasket to make 12.5 compression ratio. You guy's think it's enough? I could change to a domed piston but that more money and a new balance job. I normaly like .035 piston to head clearance but this will only net .018. I think it's a little close for a reconed stock type rod. What do you guys think?

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted December 13, 2004 03:15 PM  
Id stay at least .040 piston to head clearance. With only .018 if the piston rocks a little too much or one crank throw is off a little on the long side you could be in trouble. If you want to use the combo you have i would zero deck the block then use whatever thickness gasket is needed in combination with the heads to give .040 piston/head without cutting a bunch off of them. I would think you'd still end up 12:1 at least. More compression would help but like you said you'd either need to go domes or you could have the heads angle milled but that gets expensive. If you can run aftermarket steel heads you could look into Dart or Pro 49cc heads, and run them with flattops.

leapinlizard
Dirt Freak

Total posts: 402
posted December 13, 2004 03:23 PM  
Yeah, that's the plan. Spponsor money comes once per month so I need a combo that will work okay till Pisces Pet's pay's off. I like a zero deck with a .039 gasket but then I lose compression. 462 heads can be cut to 50cc but head gasket retention under the heat breaks the gasket's down.

I new to circle tracking, do you think 12.0 to 12.5 is enough if I can make 475 horse in a B-Mod car?

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted December 13, 2004 03:31 PM  
If there is no compression limit then more compression will always help unless you are limited to fuel like pump gas.

With so many different b-mod type classes and rules its hard to say but i wouldnt think you'd be too far off.

If you want to post the rest of your engine rules that might help as well.

leapinlizard
Dirt Freak

Total posts: 402
posted December 13, 2004 03:41 PM  
There's no compression limit but there is a min to stay competitive. Compression is torque you know

Steel block, steel heads, 2600 pounds no alky, virgin port's and any two barrel carb. Pretty simple stuff.

331 with 12.5 turning 6800 on gas on 3/8 mostly slick track with one longer corner and the others typical ones.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted December 13, 2004 04:43 PM  
Well if you can run aftermarket steel heads i'd build what you have now and put emphasis on the bottom end. Then when you can upgrade to a set of DArt 49cc heads maybe even cut them a little to get the compression up higher. Or go to a pair of vortec heads again keeping the compression up as high as you can.

Also I'd start turning it a little tighter. I'd go 7200 and depending on your vavletrain parts id prob push it a little harder if everythings good.

[This message has been edited by dirtbuster (edited December 13, 2004).]

leapinlizard
Dirt Freak

Total posts: 402
posted December 13, 2004 05:28 PM  
These heads are to be used til the local swap meet's start happening around here in may. Racing season start's in March.

A good bottom end is imperitive. The crank rods and piston all show the coorect measurment's and I had them wet magged a few day's ago. Even though the pistons aren't a forged item(hypers)they should way less than forged pieces. I'll check them for cracks every four night's till I get enough sponsor money together to get a better crank and rods with a good piston. Then I turn it 7900-8000 with a 6.40 gear.

Thanks for all the input and advice.

FASTLAP
Dirt Maniac

Total posts: 171
posted December 14, 2004 05:29 AM  
Just having a brain fade, but what was the 327 stroke? I too am interested in this type of combination. thanks

leapinlizard
Dirt Freak

Total posts: 402
posted December 14, 2004 07:36 AM  
4.0x3.25=327

robhbk24
Dirt Freak

Total posts: 372
posted December 16, 2004 04:39 PM  
go for it, i'm running a small journal 331 in my street stock and i love the thing. i bought it as a used street motor from my boss for $250 and then a week later bought the 461 heads from him for $150.swapped cams and ran it for 2 seasons 25+ races a year before i had it rebuilt and i just finished my 2nd season on it since the rebuild with no problems it's on it's way to get freshend after the first of jan. i have never had a prob keeping up with the bigger motors the only deal i have run into is that becasue i turn more rpms than the other guys usualy 600 to 800 more or so that if i travel anywhere i almost always have to change gears to be competetive whereas the other guys can travel to the other area tracks and use the same gears.

51racing
Dirt Maniac

Total posts: 138
posted December 17, 2004 09:31 AM  
I know this isn't directly related, but since they share the same stroke I'm curious if anyone is running a 307 chev and how high you rev them up?

leapinlizard
Dirt Freak

Total posts: 402
posted December 17, 2004 10:21 AM  
307 have a 3.87 bore. Not near big enough to prevent valve shrouding. Running anything less than 4.0 in pointless IMO.

badfastjr
Dirt Maniac

Total posts: 193
posted December 18, 2004 05:17 PM  
we have ran a 307 and love it as long as you turn it a lot of rpms. it lasted about 5 years without any kind of rebuild in a modified. it always had at least a 6.00 gear, If i had a block that would be the next motor that id build.

------------------
"son this aint a car its a racin' machine."

bubba0six
Dirt Maniac

Total posts: 146
posted December 18, 2004 08:11 PM  
ive got a 307 sitting under my carport if any of you want to try it

racenmotorsports
Dirt Maniac

Total posts: 169
posted December 19, 2004 06:30 PM  
Maybe y'all can help, I got to stay under 318 in my class. Right now I got a pretty much stock 283, it was the right price folks. If I put a small journal 327 crank it and bored it over 30, what else do I got to do to make it work?

Bubba, where you at?

IowaFuzzy1
Dirt Maniac

Total posts: 136
posted December 19, 2004 10:41 PM  
You'd be better off to leave the 283 crank in it and go 60 over,it'll give you a better bore stroke ratio and make pretty good power for it's size. When I was a kid we used to take 283s 125 over,that made a 301 and they were a screamer but they tended to run a little on the warm side because of the thin cylinder walls.The 327 crank 283 bore gives you 307 then 30 over will get you pretty close to your 318 limit.good luck!

robhbk24
Dirt Freak

Total posts: 372
posted December 20, 2004 03:31 PM  
if you can find it take the 283 crank and put it in the 327 block that your 327 crank came out of giving you a 302.

RACEINMUD
Dirt Freak

Total posts: 323
posted December 21, 2004 11:29 AM  
If anyone is interested I have a crank #3815822..265,283,302.forged..small journal....3.00" stroke that came out of a running motor. Make an offer, I'm in SE Colorado and I'll check on shipping cost. Also have the rods and pistons I'll throw in. I think they are 5.7 rods and 30 over flattops. Thanks, Race

Sick&Twisted
Dirt Roller

Total posts: 15
posted December 21, 2004 05:47 PM  
Idont know if you have heard of mod70 but he seems to be a main stay in the forum and im about to build him a true 327 cub motor that is a real power house for the 05 season as a try it until it blows engine. im hopeing that it will go for a season or two before i need to take a look at it.
Myself i sware by the short stroke engines they may be short in the torque but make up in the power. ive got one in my drag car that runns in the high 8s in a 3400 pound car in the 1/4 mile hope you all the best of luck hotrod

racinrobb2003
Dirt Roller

Total posts: 12
posted December 21, 2004 08:45 PM  
There is no replacement for displacement.sep more gear lol!!!!!!!!!1

madmodshoe
Dirt Maniac

Total posts: 195
posted December 21, 2004 09:52 PM  
Lizard
500hp? 400hp on a 2bbl is attainable with about 14to1 compression and 383+ cubes. All good stuff to get there. The two barrell starts drop off dramitacally at about 7200 rpm, so gear don't cut it in a b mod. Cubes with compression run with a 7200 chip is the way to go. JMO

leapinlizard
Dirt Freak

Total posts: 402
posted December 22, 2004 03:05 PM  
500 CfM Holley.

Only flows 500 cfm no matter what the cubes. Assuming %100 VE here, a 383 will run out of air at 5500. A 327 will continue pulling air to 6400 with out pulling a vacuum below the throttle blades. After the engine exceeds this, all you can do is raise compression to get the combustion pressure up to levels before the theoretical negative vacuum. 327 doesn't make torque like a 383ci. But, you can make up that torque with mechanical leverage. A 327 with less flywheel torque may prove to be easier to drive for a newbie (me) because blowing off tires will be harder to do. Even if you manage, the gear will help the engine RPM get above the max torque range where horsepower begins to trade for torque. (After 5252rpm)

I should clarify, my intentions are not to discuss when an engine runs out of usable power, but only when no additonal air is being added due to barometric pressure to establish a baseline for further calculations.

[This message has been edited by leapinlizard (edited December 22, 2004).]

madmodshoe
Dirt Maniac

Total posts: 195
posted December 22, 2004 09:52 PM  
Sounds like you have it all figured out....if we were racing flow bench's. You are assuming that the 327 will automatically pull all 500 cfm from the carb. Compression is what makes torque and torque is what wins races. I had a 327 with a set of double humps that I turned 8200 religously. No compression, no torque, but **** it sounded good at the back of the pack!

The whole point of my post was that you are not gonna get 500hp from a 327 with a 2bbl.
You can race anything you like. That is how you learn what works and what doesn't, which by the way separates the winners and the dreamers.

leapinlizard
Dirt Freak

Total posts: 402
posted December 23, 2004 08:01 AM  
(...if we were racing flow bench's.)

What else you got to do right now? lol

(You are assuming that the 327 will automatically pull all 500 cfm from the carb.)

I think I'm missing your point. Are you saying 327ci can't pull 500 cubic feet of air at any given time, no matter what the RPM?

(No compression, no torque, but **** it sounded good at the back of the pack!)

That's funny

Why couldn't you get compression? I get 13.2 out of mine with a flat top. It's probably more than what most mid packers have at my track. The combo I have in mind...Callies crank 3.25
GM 020 splayed cap block
JE flat top piston, piston .005 out of the hole...
Rods are 5.7...don't have a brand picked yet
462 heads milled to 50 cc. Ported by me...I've done about 20 set's of heads in my life...just so you don't get the idea that I read a book somewhere and now think I'm Robert Yates or something. I'll be running these heads for the first 10 races then switching to something like Brodix.

mudd on the tires
Dirt Full Roller

Total posts: 42
posted December 23, 2004 01:38 PM  
if the track rules are 2 barrel carb. and stock heads. how would the vortec heads with bowtie intake on a 283, 307, or 327 work?? what would you have to do to the block to get it to turn the high rpm's that it needs to turn.. the track is 1/4 mile.

madmodshoe
Dirt Maniac

Total posts: 195
posted December 25, 2004 12:02 AM  
I could not get compression because I raced that motor in stock only head division. Milling to 50cc is an option, but it is far cheaper to purchase iron eagles or pro's. They flow much better and are far less likely to crack or fire slot.
As far as turning high rev's with a two barrell, try it you may like it. The problem is the cam you will need to do it will be a total turd on restarts.
Why would you want stress your valve train that much each week? Looks like you have a good start on the short block. You would not have any more money invested into a 383.

Not trying to offend you, but I myself tried to reinvent the wheel because I was to hard headed to listen more experienced racers. It cost me lot's of money to prove them right in the end. Hope you can make it work!

madmodshoe
Dirt Maniac

Total posts: 195
posted December 25, 2004 12:04 AM  
BTW, you still are not gonna get 500hp from a 2bbl 327 with hump heads.

robhbk24
Dirt Freak

Total posts: 372
posted December 25, 2004 08:35 AM  
with running a smaller cui motor you also have to take in consideration do your rules allow a weight per cui ratio. up here it is 9 lbs per cui min 3000lbs. i run a 331 so i have to weight at 3000lbs where as the 355 and bigger motors have to weight 3200lbs and up. i get a weight break of 200lbs min over everybody else i think and it seems to work that any minute horsepower loss i get from running a smaller motor i make up for in weight savings. if everyone has to weight the same then i can see the bigger is better theory.jmo

leapinlizard
Dirt Freak

Total posts: 402
posted December 27, 2004 09:31 AM  
BTW, you still are not gonna get 500hp from a 2bbl 327 with hump heads.


Prolly not, but I only need 475. I'm sure I can do that.

Milling to 50cc is an option, but it is far cheaper to purchase iron eagles or pro's.

Can you elaborate? The last I checked head prices those heads were 5 times the cost of what I have in my heads. I just got back my heads. It cost me 275 for springs for .600 lift, screw in studs, guide plates and flat milling .050 to 47 cc. I had the part's already so that helps.

The problem is the cam you will need to do it will be a total turd on restarts.

Yeah, perhaps. I thought of that to but we get the entire back stretch. We can't pass untill the stripe out four. By that time were close to speed anyway. But it might hurt a little.

You would not have any more money invested into a 383.

If you remember, I didn't pay for the short block. I got it for trade and two hundred bucks. So yes, I would have spent lots more on a short block 383.

Not trying to offend you, but I myself tried to reinvent the wheel because I was to hard headed to listen more experienced racers. It cost me lot's of money to prove them right in the end. Hope you can make it work!

Don't worry, I don't affend easily. I don't know about the reinventing the wheel part, but I have never been known to follow the leader, (Pun intended) a different drummer, what ever you want to call it. If you follow someones footsteps, your alway's a step behind. Can't remember where I read that, but I liked it. I don't intend to tell you what to think either, but I am relizing the more I hear about dirt racing, The truth lies somwhere in the middle of the pile.


Hard headed? me? naw? never in my life...


lol

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