Index Racing (Engine Build and Tips/Tricks)

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72DMag

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Before anyone reads the post below pretty sure I'm gonna open up a can of worms but here we go.....

A local drag n drive event is changing the slower street class to index racing next year. I have no experience with index racing and looking for help and any suggestions for an engine build and driving tips/tricks.

Let's say the index is 12.00 and car with me in it weighs about 3400lbs. What's the goal? To run quicker then 12.00 and short shift? What horsepower should I look for with engine build? (Engine can be 318 or 360). Say an engine is built that is too fast or slow, what do you do at the track to run on the dial?

I feel like build it faster then slow car down by Short shifting, take out timing, change tire pressure, deep stage (adds ~ .1 to et in 1/4 mile). etc. However, having no experience with this I'm really looking for any advice where to begin to build the engine then driving tips. Thanks!!
 
You definitely need to be able to run faster and tune back…however you get there. At 3400 lbs you need about 400 hp at the motor. Keep in mind that’s at your worst ambient conditions. The more power you make over that, the tougher it may be to dial it back, especially when the air is better.

Do you know what kind of tree (3 bulb, .5 pro tree)? Trans brake allowed, or foot brake? These will help you decide car setup too.

Will they allow restrictor plates? You can get a set of them, then swap out based on air.

Have fun! Our 12.0 class is pretty competitive…yours will get there pretty quick, learning curve is steep and some folks will already have it figured out.
 
Talk to someone who runs Stock Eliminator. They know all about that concept.
 
@dusterbing the peace

The event is the midwest drags (Home - Midwest Drags). From what a friend told me they are trying something new next year and doing the street eliminator class with a 10.0, 11.0, and a 12.0 index races. At this time I can't find much on their website for rules but my car details for now are below:

1976 Roadrunner (A57 Volare)
will be a footbrake car (My preference)
Car has B body 8 3/4 with 3400lb super stock springs
742 case with 30 spline spool and 4.56 gears
A500 transmission with manual fwrd valve body, low gear set
3000 stall lockup converter

Engine:
I would like to utilize one of the many 318's I have for this car. (They r collecting dust)
I have kb399 dome pistons on 340 bushed rods
I have 302 heads
I have a comp cams 268 grind flat hydraulic cam (224/230 0.477/0.480 lift) I doubt this will be enough???

Mickey Thompson tires on summit aluminum rims. 26 in front 28x11 drag radials in the back.

My goal is to hit the 12.0 index but I also want to get 15mpg with the overdrive trans. Car has a 15 gallon fuel cell. I think you are right about 400hp if I had a 904 but from what I've read the weight and friction of the overdrive trans will slow me down about .5 tenths.

Resized_20220801_170016.jpeg
 
72DMag said:
@dusterbing the peace

The event is the midwest drags (Home - Midwest Drags). From what a friend told me they are trying something new next year and doing the street eliminator class with a 10.0, 11.0, and a 12.0 index races. At this time I can't find much on their website for rules but my car details for now are below:

1976 Roadrunner (A57 Volare)
will be a footbrake car (My preference)
Car has B body 8 3/4 with 3400lb super stock springs
742 case with 30 spline spool and 4.56 gears
A500 transmission with manual fwrd valve body, low gear set
3000 stall lockup converter

Engine:
I would like to utilize one of the many 318's I have for this car. (They r collecting dust)
I have kb399 dome pistons on 340 bushed rods
I have 302 heads
I have a comp cams 268 grind flat hydraulic cam (224/230 0.477/0.480 lift) I doubt this will be enough???

Mickey Thompson tires on summit aluminum rims. 26 in front 28x11 drag radials in the back.

My goal is to hit the 12.0 index but I also want to get 15mpg with the overdrive trans. Car has a 15 gallon fuel cell. I think you are right about 400hp if I had a 904 but from what I've read the weight and friction of the overdrive trans will slow me down about .5 tenths.

View attachment 1715968250
Click to expand...
Love the car! I think Myron (@Locomotion) does a lot of this....I know he races, maybe he'll chime in.
 
Index racing, 10.0, 11.0, super comp, super gas and super street is a completely different approach than dial in (bracket, stock and super stock) racing.

For a fixed index deal, make it run .5 quicker in the worst air and “throttle stop” it back somehow to run the number. Goal is as much MPH as you can get, running that particular index. It’s up to your experience level to set it up a bit quicker and race the finish line, or set it up to run the number and run it flat out.

Don’t ask the stocker guys; talk to the super comp, super gas and super street guys.
 
RustyRatRod said:
Love the car! I think Myron (@Locomotion) does a lot of this....I know he races, maybe he'll chime in.
Click to expand...

Thanks, but I ran IHRA Stock since 1999 & tried to get into NHRA Stock (Under index & dial-in). Ran index a couple of times at a local track, but not my cup of tea.
 
Locomotion said:
Thanks, but I ran IHRA Stock since 1999 & tried to get into NHRA Stock (Under index & dial-in). Ran index a couple of times at a local track, but not my cup of tea.
Click to expand...
Thanks for chimin in Myron! I wasn't exactly sure which class you ran. You been doin ok?
 
Your gonna have to do a lot of work to get 400 hp out of 302 heads.
With that cam your gonna need like eddies maybe even ported ones.
 
72DMag said:
@dusterbing the peace
Engine:
I would like to utilize one of the many 318's I have for this car. (They r collecting dust)
I have kb399 dome pistons on 340 bushed rods
I have 302 heads (For a door stop, yes....on your engine, NO)
I have a comp cams 268 grind flat hydraulic cam (224/230 0.477/0.480 lift) I doubt this will be enough??? (No, it won't be enough)

View attachment 1715968250
Click to expand...
This engine will not get you there @ 3400 lbs. I run a 10.5 index, and like others have said you need to be able to go under the index even in hot humid weather (for example, my car will go 10.3 in 95 degree humid air).

The other thing you need to look at is what kind of tree they will be using (0.500, 0.400, instant green). If you want to be competitive you need to be able to cut a light. My 10.5 index is instant green...which means I need my car to react as fast as possible. I have also run this same index on a 0.500 tree.....VERY different setup (i.e. I will red light on a 0.500 tree with my instant green setup).
 
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Been index racing for over ten years now ( 11.50 ) and love it ! and prefer it to regular bracket racing. We run on a 5/10s pro tree. My combos have been small blocks in the 525 hp range running in the 10.80-11.00 range depending which motor I have in my Dart is 3150 lbs. with me in it. I am killing about half a second most of the time. You have to be able to run two to three 10s quicker than the index. Just going the index ( 11.50 for example ) isn't enough as most of the competitors are all slowed down and can adjust for weather and track conditions. My car leaves hard and I am foot braking my mph isn't the best but my car is very competitive and I have done pretty well. I have tried the Willys adjustable plate system as well as the E.Z. plate and found that they killed to much mph and went back to my bolt system a modified Moroso stop that bolts to the rear carb stud. I simply turn the bolt out or in to adjust how fast or slow I want set up for. I am currently working on a different type of throttle stop : I purchased a Biondo electric throttle stop since its electric function isn't legal as per the rules here I removed the solenoid and added a spring to operate the function the solenoid used to I like it because it also has a scale and a knob both with increments for accurate settings I haven't tried it yet though.

167441FB-7DEA-4C92-856E-5ED521B0D77B.jpeg
 
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For index racing your car is going to need to be able to run the index in the worst air condition of the year. So I'd shoot for at least 2-3 tenths quicker in good air for 1/4 mile, maybe 1-2 tenths if 1/8 mile racing. Than you need some time of "system" to slow the car down consistently to run as close to the index as you can. Either via adding weight, an adjustable throttle pedal stop, restrictor plate system, etc. My wife and I run the 7.10 index at our track. My car goes 6.70s, her goes 6.80s. In good air I can run 7.10s by unhooking the secondary, but in crappy air I can't. I now have a ez plate system on my car that works great. Her car doesn't have enough room for the ez plate system so I have an adjustable throttle cable on her car and add weight to make it run the index.
 
Thanks everyone for all the info!! Much appreciated :)

Okay so definitely sounds like I need to build 318 for faster and do some kind of throttle regulation. (either stop or adjustable cable) Maybe keep the 302 heads and do solid roller camshaft? I have a decent budget to work with. My only problem with putting aluminum heads on a 318 is that the 2.02 intake valve is a little big. Yes it can be done and has been done but it's overkill imo. If I go to J heads then compression drops but I do have a set with 1.88 intake valves.

@BVoelzke I saw deep written on your car. They allow deep staging for instant green when index racing? Deep stage honored for a pro tree for index races?
 
72DMag said:
Before anyone reads the post below pretty sure I'm gonna open up a can of worms but here we go.....

A local drag n drive event is changing the slower street class to index racing next year. I have no experience with index racing and looking for help and any suggestions for an engine build and driving tips/tricks.

Let's say the index is 12.00 and car with me in it weighs about 3400lbs. What's the goal? To run quicker then 12.00 and short shift? What horsepower should I look for with engine build? (Engine can be 318 or 360). Say an engine is built that is too fast or slow, what do you do at the track to run on the dial?

I feel like build it faster then slow car down by Short shifting, take out timing, change tire pressure, deep stage (adds ~ .1 to et in 1/4 mile). etc. However, having no experience with this I'm really looking for any advice where to begin to build the engine then driving tips. Thanks!!
Click to expand...
@pittsburghracer is also a great reference for racing tips and tricks. He has been racing for a very long time
 
Stock 302 ain’t a 400 hp head even the stock 1.88 J heads won’t get you there,
Your either need to port the heads for the power level you want or cheaper to buy aftermarket heads especially if you got to get someone else to do the work.
2.02 are fine with a 318 especially after boring your not that far from a 4” bore.
 
Plus mileage was important to you building power with head flow and a milder cam will get better and more streetable than more cam less head flow, why LS and Hemis work so well.
 
72DMag said:
Thanks everyone for all the info!! Much appreciated :)

Okay so definitely sounds like I need to build 318 for faster and do some kind of throttle regulation. (either stop or adjustable cable) Maybe keep the 302 heads and do solid roller camshaft? I have a decent budget to work with. My only problem with putting aluminum heads on a 318 is that the 2.02 intake valve is a little big. Yes it can be done and has been done but it's overkill imo. If I go to J heads then compression drops but I do have a set with 1.88 intake valves.

@BVoelzke I saw deep written on your car. They allow deep staging for instant green when index racing? Deep stage honored for a pro tree for index races?
Click to expand...
I just noticed that you probably could not see what I wrote in the replied quote above (post#11). The 302 heads are not a good choice for this application (they don't flow well at all). I would go with an aftermarket head (lightly ported Edelbrocks or Trick Flows would work).
 
flyfish said:
I just noticed that you probably could not see what I wrote in the replied quote above (post#11). The 302 heads are not a good choice for this application (they don't flow well at all). I would go with an aftermarket head (lightly ported Edelbrocks or Trick Flows would work).
Click to expand...
Yes I deep stage on the pro tree and it is allowed at the few tracks I run the index program at.... Just a reminder.. going deep makes your E.T. and 60 ft a tenth slower so shallow I am set up to run 11.40 which puts me at 11.50 deep ..my 60 fts. are 1.49 - 1.51 shallow ( 1.59-1.61 deep ) leaving at 2,000 rpm
 
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72DMag said:
Thanks everyone for all the info!! Much appreciated :)

Okay so definitely sounds like I need to build 318 for faster and do some kind of throttle regulation. (either stop or adjustable cable) Maybe keep the 302 heads and do solid roller camshaft? I have a decent budget to work with. My only problem with putting aluminum heads on a 318 is that the 2.02 intake valve is a little big. Yes it can be done and has been done but it's overkill imo. If I go to J heads then compression drops but I do have a set with 1.88 intake valves.

@BVoelzke I saw deep written on your car. They allow deep staging for instant green when index racing? Deep stage honored for a pro tree for index races?
Click to expand...

If you have a decent budget you could run ported eddies and have the intake seats replaced and use smaller valves…1.88 or maybe 1.94? Would of course choke some flow, but nothing like those 302s will. Aluminum would also shave some weight.

You’re gonna want a cam in the higher 230s with 550+ lift. Your gear and tire will put you 6200-6500 through the traps depending on how much you need to kill, is that okay with what you’re planning?
 
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