I have no comment except to say it is THIS situation that separates the men from the boys. When getting that little bit of an edge over your competitors in a purpose built engines. Where the smallest detail stands between winning and second, third, or fourth place.

Can't wait to see the responses.

 

at the local circle track there is a cubic inch rule that u cant be over 360 ci. another rule says u cant be over 155lbs compression which is very light for a 350ci eng.. as far as the carb it Must be a Single Holley 4412 two-barrel with stock venturi, metering blocks and boosters, horn stays on, and choke plate can be removed...... and now for my question

since the 350 block is kinda starving with the smaller carb and low compresion i was wondering if a smaller block (maybe 327) could make more power there is a gear rule in place so max revs would be around 6200..any ideas guys?

First Off, what length is the circle track, dirt or paved, banked or flat? How long are the straights? Are you allowed to use weight jacks, or not?

What are your weight restrictions, and the type of fuel allowed?

Are you currently racing, or just starting out, or thinking about it?

 

Is that you talon0713?
If not, I apologize and suggest you read this thread.....
http://www.hotrodders.com/forum/pssible-make-283-into-327-stroker-150736.html

 

Max cubes, max compression allowed...using a smaller engine is a waste of time.

I would borrow the compresssion gauge they use to check compression to be sure I am within 1 psi of the max according to them.

Running a slightly larger overlap cam will help with reducing compression at cranking speeds so you can run higher static compression.

Run a slightly smaller dia tire as wide as possible (cut them if you have too) to get the revs up, if you can afford it run a 30 series tire. I wouldn't worry about the carb, the engine will draw what it needs, just make sure it gets cold air from the hood in a high pressure area like the cowl.

Tune it right and kick some butt.

 

Length: 1/3 mile
Track Width Straightaway: 58 Feet
Track Width Corners: 50 Feet
Track Width Backstretch: 65 Feet


paved, slight banking... 2500lb weight 56% left weight max. open fuel rules

 

Okay, what's the gear ratio set forth by the track gods and are you limited to an automatic trans?



Larry

 

Running a slightly larger overlap cam will help with reducing compression at cranking speeds so you can run higher static compression.

This is sound advice... what is your lift rule? .410? .450? Or do you have a vaccum rule in effect also?

I think we already debated this 327 vs. 350 myth a few posts ago, so no, I wouldn't go smaller on the cubic inches.

Good god man that's a small track what the heck are running for a gear? 5.36? or lower?

 

I would try...

4.155x3.25 358ci
6.20 rod
17:1 compression
cam duration at .260@.050
1.7 rockers
and the best carb you can afford to pay a pro.
turn it 9200 if you have the valvetrain.

As far as getting the crank compression legal, put a 4:1 gear driven starter on it with the 168 tooth flywheel and it'll turn slow enough to show it's legal. especially after the money race the battery will be low enough it won't crank well

You gotta a smart driver with this though. It will come apart at WOT at low rpm.

 

at the local circle track there is a cubic inch rule that u cant be over 360 ci. another rule says u cant be over 155lbs compression which is very light for a 350ci eng.. as far as the carb it Must be a Single Holley 4412 two-barrel with stock venturi, metering blocks and boosters, horn stays on, and choke plate can be removed...... and now for my question

since the 350 block is kinda starving with the smaller carb and low compresion i was wondering if a smaller block (maybe 327) could make more power there is a gear rule in place so max revs would be around 6200..any ideas guys?

You're in the game between the effects of static compression ratio against dynamic compression ratio.

I'm sure what they check is cranking pressure which is first the effect of static compression that being the division of total cylinder and combustion chamber volume by volume above the piston. Oh this leaves ever so much space to play. A cam with a lot of overlap and or late closing intake bleeds a ton of pressure while cranking. So if you've got (or the rules allow, a wild cam, you can bump the static ratio up quite a ways before you bang on 155 psi cranking.

Then there is that cam, it works with the heads and your carb limitations in strange and mysterious ways. That is a high overlap, late closing intake valve timing combined with a somewhat too small intake tract and a too small carb really jacks the port velocity up as the revs climb. This really begins to pack the cylinder with ram pressure from the port velocity. The effect is that the in-cylinder pressures, what's called the Dynamic Compression Ratio, goes way up with the revs, so the engine react's like it has a higher Static Compression Ratio.

Now the down side of insufficiently sized ports and carb is that the motor will run out of breath sooner than if it had some honkin' AFRs and a Dominator on it. So, if you can do porting, starting with a small port and doing a little cleaning so it flows more without getting big, a super valve job, and 5 angle if the rules allow any of this will help get mixture into the engine. Reversion cones in the headers, if permitted, will help keep the exhaust reversion from blowing mixture out during overlap.

I can't tell you how this temps me toward 305 heads with 350 valves and D dished pistons to dial the static compression in while developing a humongous swirl and keeping a real tight squish/quench. This just works the daylights out the mixture.

Long cam duration can be used to add time in which the too small ports and carb will have with which to fill the cylinder.

The Devil's in the details and rolling onto the track with the highest power engine isn't always the recipe.


Bogie

 

i've been told that cam overlap can only hide so much b4 it starts to steal more power then the extra compression is worth...lots of good advice here though...although a few guys arent reading my rules, i dont mind bending them but... gotta keep it looking legal!

 

a 327 crank in a 400 block would be the way to go, BUT its more expensive than going with a 350. a 350 will be better than a 327. And the DCR is the DCR regardless of displacement

 

here's a vacuum rules circle track motor build article:

http://www.circletrack.com/enginetech/ctrp_0812_street_stock_vacuum_rules/index.html....

then do go back to the home page and read thru "ALL" the different tech sections articles in each...
(best lap time is how the "whole" car works)

you need to more closely study all the rest of the track motor rules to make a plan,,,
what you have posted so far is a kind of modified/outlaw type "no" restrictions race...
(350, 2V, 15Hg and then anything you want to do,,,which is not typical to pass tech inspection)

 

here's a vacuum rules circle track motor build article:

http://www.circletrack.com/enginetech/ctrp_0812_street_stock_vacuum_rules/index.html....

then do go back to the home page and read thru "ALL" the different tech sections articles in each...
(best lap time is how the "whole" car works)

you need to more closely study all the rest of the track motor rules to make a plan,,,
what you have posted so far is a kind of modified/outlaw type "no" restrictions race...
(350, 2V, 15Hg and then anything you want to do,,,which is not typical to pass tech inspection)

it is for a modified class, and basicly that is all the rules within the engine....there are lots of dimensional / weight rules for the chassis but first im trying to come up with the "power Plant" that willl kick *****

 

my $.02:
"no rules"=
unless you have MEGA bucks, race at a different motor (rules) track or class....

not likely that track can offer purse's to cover a reasonable amount of your total operating cost every week and be competitive....

the track owner is 90%+ concerned about drawing a crowd for $$$$ in his pocket....

and who ever has the most to spend on his motor and car (repeatedly) will win....

 

a 327 crank in a 400 block would be the way to go

agreed 100%

 

...... open fuel rules

I'm thinking NITRO

Shane

 

I'm thinking NITRO

Shane

i meant open as in race fuel is allowed.... nitro would be pushing it
:mwink:

 

This is the problem with limited classes of racing, they are designed to be "budget friendly" when really they can be much more expensive than open classes because you are forced to spend a lot of time and money on motors that don't make that much power and you end up spending more at the machine shop for the time it takes to push the rules.

In the end it is the guy that spent the most on dyno time that usually has the best motor in limited classes.

Recently wissota started using a "whistler" to check compression instead of a compression gauge. I hate that thing, it will measure a full point under what your actual compression is. So if the rules are 9.5:1 and you spend all your time and efforts getting a motor that is just right and calculates to 9.49:1. Then you get picked and they whistle the motor at 8.6:1 it makes a guy pretty angry knowing he could have been off by up to 10.4:1 and it would have been ok.

Bottom line is that there is no fair way to check compression so they came up with a "standard" and even though mathematically it comes out correct the whistler says otherwise so everyone has to follow it. Even though you can take your car to a track 50 miles away and it will whistle different than the one at your home track...but still way to low.

Sorry about the rant, I just hate restricted class rules sometimes....if you couldn't tell that was a personnal experience.

 

This is the problem with limited classes of racing, they are designed to be "budget friendly" when really they can be much more expensive than open classes because you are forced to spend a lot of time and money on motors that don't make that much power and you end up spending more at the machine shop for the time it takes to push the rules.

In the end it is the guy that spent the most on dyno time that usually has the best motor in limited classes.

Recently wissota started using a "whistler" to check compression instead of a compression gauge. I hate that thing, it will measure a full point under what your actual compression is. So if the rules are 9.5:1 and you spend all your time and efforts getting a motor that is just right and calculates to 9.49:1. Then you get picked and they whistle the motor at 8.6:1 it makes a guy pretty angry knowing he could have been off by up to 10.4:1 and it would have been ok.

Bottom line is that there is no fair way to check compression so they came up with a "standard" and even though mathematically it comes out correct the whistler says otherwise so everyone has to follow it. Even though you can take your car to a track 50 miles away and it will whistle different than the one at your home track...but still way to low.

Sorry about the rant, I just hate restricted class rules sometimes....if you couldn't tell that was a personnal experience.

Here here! Those restricted class races cost more than a "real" modified class in the long run, and if you don't own a machine shop and engine dyno your never going to be competitive.

Save up and buy a real race car with a spec engine thats reliable and get in there with the pro's, racing with a bunch of weekend yahoos driving junkyard crap is a lesson in crash and burn....for your wallet.

I learned this lesson in Vintage sedan road racing, the money it takes to make a street car into a race car is more than it takes to buy a real tube chassis Formula Vee car and nowhere near as reliable, then you have the noobs out there that either are super slow or looking to take some one with them in an off track excursion or you have the daddies boy who shows up with a nearly new late model Porche (trailered) and decides he can just flout the "no passing rule" on corners during the race and pushes you off the track because he doesn't have to drive it home.

I know it looks tempting and seems cheap but in the long run it is neither fun or cheap to run up front.

In the spec pro classes its skill and attention to detail that wins, its a place where your time and effort will pay off.

Heed the warning, its been said twice.

 

I like budget restricted or claimer classes for that reason. If someone can claim your long block for 2G's you're not going to be runnig really exotic stuff unless you like giving money away.

some of my ideal race rules are factory style suspension, car claim rules, engine claim rules, and cranking compression rules (if the RPM and method is clearly outlined).

It allows a LOT of flexability but it still keeps things on a relatively even playing field. Machinists have an advantage if they want to put the time in, but they're just saving themselves money someone else can be just as competitive if they don't mind putting up the cash for it. It sort of equalizes the time & talent VS fat wallet playing field.

 

Let's face it guys.
Circle track or open track are big money games. period.
$ drove me out of circle track,
But doggone $$$$$$$$. :nono:

If I won the lottery, I would go to Indiana/Ohio and run midgets. :thumbup:

Money is the reason that drag bracket racing is so popular everywhere.
You can do it in your everyday hot rod,
do it every week,
and whatever you can afford to have,
you fit in somehow.

Right now I am thinking SCCA, but the meets are so darn far away $$$$

 

i meant open as in race fuel is allowed.... nitro would be pushing it
:mwink:

Does it specify it....This seems like one of those classes that has a large grey area and it can be stepped into pretty freely.

Shane

 

?

I think we already debated this 327 vs. 350 myth a few posts ago, so no, I wouldn't go smaller on the cubic inches.

Thats funny, we must have read diffeerent threads because I recall another recent thread where a circle track racer was lamenting that a 60 year old guy with his 327 was kicking all of the other guys with their 350s butts..

Its all about the total package.

If it were me though I would probably just do as much as possible to refine the 350. Money wasted on another begining is money that could be used to make your existing motor a screamer.