Moparchat - Home of MOPAR enthusiasts worldwide!



Go Back   Moparchat - Home of MOPAR enthusiasts worldwide! > Technical Forums > Circle Track Chat

Click here to search for Mopar cars and parts for sale.


Reply
 
Thread Tools Display Modes
  #1  
Old 08-08-2001, 05:10 PM
Racedude_5 Racedude_5 is offline
Inactive User
 
Join Date: Sep 2000
Location: Mayfield Ky
Age: 60
Posts: 101
Lightbulb 400 big block in circle track?

I have a freind who is interested in putting togather a prostock car at our local track and running a 400 big block in it. The rules are basicly, 410ci limit, steel heads, gas or methonol, roller cams allowed, must run front clip but can be a tube car from there on back, 3,000lb and they run late model tires 11" tread, with an aluminum latemodel body. Some guys are taking old late models and putting a front clip under them.
I drove one of these cars for someone last year with a good chevy(whatever that is) 350 in it, These cars have a lot of traction withe the tires they run and once you get it pointed where you want you can plant the throttle and not have a traction problem because the car is so heavy.
I believe we can put the 400 in the car and still balance it out well since we have to hang about 500lb of weight anyway.
Would the motor make a good one? Are good steel heads availible?
Reply With Quote
  #2  
Old 08-09-2001, 01:30 AM
sanborn sanborn is offline
Inactive User
 
Join Date: May 1999
Location: shelbyville,tn,USA
Posts: 2,880
Default

The 400 block is tough, plentiful and can be built into a serious engine. The big problem is weight although the 3000 lb. limit does help.

First, let me address the weight and I compare everything against the small block GM because that is what you will run against. The block is heavy about 225 lbs. But, with a lot of grinding(dirty, messy work) you can get the block down to about 200 lbs. The next area is the water pump, you can save 17 lbs. real quick by discarding the standard pump and adapt a aluminum GM pump to it. It really is not hard to do, just get 2 pieces of 3/4" aluminum and make 2 set of mount holes, one set for the GM pump and another set to bolt it to the block. These two changes will save 40 lbs. and get you to within 50 lbs. of a GM.

Now, to the good part. The 400 is an economical source of power, not cheap but economical. The 4.34" bore/ 3.36" stroke is great for dirt. Find a steel 383 crank(same stroke), buy a good, light set of aftermarket pistons, use .990 pins. You can use stock rods but after you get thru with them you will have almost as much in them as a set of Eagle rods. A friend just bought a set of Manley sportsman rods for $500- and they look real good. By the way, the 383 crank can be worked on, polished, deburred and you can get it down to about 56-58 lbs. which is about what a standard weight 3.75"GM aftermarket crank weighs. Buy a good aftermarket aluminum damper(Rattler, Innovators West. etc.) Of course, a good balance is required.

You have several choices for cylinder heads; 906, 915 or 452s. All are decent(not great) and can be pocket ported and can be made to work OK. Stage 5 heads are probably the best and can be purchased from Mopar. I assume you can't port the heads. In any case, use 2.14"/1.81" valves (if rules allow). You can get roller cams from several sources. I prefer Comp rollers (price). Get a cam with moderate lift(.620") and about 260/270 degrees duration @.050". You want more exhaust duration because the exhaust ports are weak compared to the intake. More exhaust duration helps to balance flow needs. Buy a good set of aftermarket roller rockers. The iron rockers cause too much side force on the short guide(shortens guide life). And learn about getting the proper rocker geometry!

Its been years since I built one of these, I don't know what kind of intake is best for this combo now. A seriously ported Team G used to be the best, there is probably something better now. I wouldn't go too large on the carb, probably a good 750 would be a good start point. Big blocks like Dominators but you might not have enough head for it to work with good throttle response.

These large bore/short stroke engines like to turn RPM plan to turn it 7200-7500. You will probably have to build your headers, use 2" tubes to a 3.5" collector. Schoenfield will build them for you but you will probably have to wait 3 months.

Build or buy a 10 qt. oil pan. Use the standard windage tray(enlarge slots for more oil escape) and fabricate a crank scraper(.030" clearance). Oil control is very important. Make sure the oil level is at least 1" below the windage tray. A Mellings pump with a Milodon pickup will probably handle you oiling needs. Enlarge all oil holes in the block 1/32"(buy the long drills necessary to do it) and round all sharp corners in the oil passages.

Hope I didn't tell you too much.
Reply With Quote
  #3  
Old 08-09-2001, 11:05 AM
Racedude_5 Racedude_5 is offline
Inactive User
 
Join Date: Sep 2000
Location: Mayfield Ky
Age: 60
Posts: 101
Biggrin

Thanks for the information Sanborn it was very helpful. Somthing I also forgot to mention about the rules is that most cars are running about 110 wheelbase amd the rules will allow us to shorten to 101" which sould really let us transfer the weight to the rear wheels. I also checked and there are no restrictions on valve sizes. you can checkout the rules at www.klms.com under rules for limited sportsman
Reply With Quote
  #4  
Old 08-09-2001, 01:36 PM
sanborn sanborn is offline
Inactive User
 
Join Date: May 1999
Location: shelbyville,tn,USA
Posts: 2,880
Default

I looked at the KLMS rules posted on their web site. They say nothing about cylinder heads except they must be iron. Can they be aftermarket? Modified? If the iron heads are open, you could spend a ton of money on these engines. For once you open up the heads you are now talking about a 600+HP engine. Please verify what can be done to the heads and get back to me. I might want to change my recommendations. You don't want to go up against those CNC ported, 14 degree, GM heads($6500) with a big block Mopar head.

On another subject, you are fortunate to race at KLMS. Beautiful facility. We raced there several times with Hav A Tampa a few years back. But it seemed like every time we were there we had horrible luck.
Reply With Quote
  #5  
Old 08-10-2001, 10:24 AM
Racedude_5 Racedude_5 is offline
Inactive User
 
Join Date: Sep 2000
Location: Mayfield Ky
Age: 60
Posts: 101
Default Heads

You are allowed to run aftermarket heads. I know some of the guys are running world products heads and some Dart heads. The class is not policed real close exept for some whineing and it was rumored last rear that the teck guy which is on the crew for the winning car was letting him run alluminum heads.
I currently run a modifoied at klms and am starting to get it lined out and doing better, we hope to be in the top 5 this weekend and were in the top 10 last weekend.
KLMS is a nice facility. If you ran there last year you should come back. They done something to the track, I cant put my finger on exactly what it was but now you can run about any grove you want and feel comfortable going 3 or 4 wide. Last week in the mod feature they went 7 wide in a turn more than once (thank goodness that was behind me) My father in law has a video of the mods 5 wide in the turn and nobody bumped.
If you come up again let me know I might be able to get you some help with a base setup for the track, Randy Sellars the 95 u.m.p. national late model champion is my brother in law, The crew chief on Rod Reed's car that finished 2nd last week in the late model feature is also my brother in law. We have a guy up here that should be running full time with the Hav-a- Tampa guys but doesnt have the funding so he stays here and wins every feature so to finish second is like winning.
Reply With Quote
  #6  
Old 08-10-2001, 02:21 PM
sanborn sanborn is offline
Inactive User
 
Join Date: May 1999
Location: shelbyville,tn,USA
Posts: 2,880
Default

World Products and Dart heads are not a big concern. The big block Mopar heads can flow with them generally(especially if you get Stage 5s). The Pro Products heads are the ones to be concerned about. They are raised port(1 1/4") cast iron versions of Cup heads.

We have run well at KLMS, just our luck has been terrible. Spun a rear brake caliper bracket, drove straight into the wall, kiss away one frame. Broke a rod bolt, kiss away one aluminum block. Bent a "J" bar in a qualifying race while running second. Oh well.
Reply With Quote
  #7  
Old 08-10-2001, 03:18 PM
Racedude_5 Racedude_5 is offline
Inactive User
 
Join Date: Sep 2000
Location: Mayfield Ky
Age: 60
Posts: 101
Default

Sorry you have had bad luck up here. Let me know when you are comming up again. That would be cool to have a mopar wi both LM and Mod and if my freind gets a mopar pro to have him win also. I bet we could get that published in Circle track mag!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Brand New Circle Track Ultra Light Short Block For Sale Mr5racing Circle Track Chat 1 08-25-2014 12:51 AM
Circle Track Mag alaskaracer Circle Track Chat 2 04-16-2013 05:23 PM
Circle track oil pan MerrittRacing Circle Track Chat 16 04-04-2008 05:55 PM
R-3 block and 3.46 Circle track crank 4 sale. Plymouth10 Rear Wheel Drive - Parts for Sale 1 12-06-2006 11:20 PM
Any circle track big block ideas? Ez Eddie Performance Talk 2 03-25-1999 04:00 PM




All times are GMT -4. The time now is 11:31 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
. . . . .