I am currently running a 1970 Plymouth that weighs around 3120 lbs. The car consistently runs 7.15 in the 1/8th. I would like to get the car down to run in the 7.0 index class, so I am looking at a few options and would like to hear peoples opinions. Here is my current setup:
440 engine
Heads - 906 ported w/1.81 & 2.14 valves
Competition Cam - solid .525 lift, 248 duration, 110 Lobe Sep
Intake - Weiand Team G
Carb - 1050 Holley Dominator
Headers - Hooker Comp 1 7/8
Coil - MSD Blaster
Ignition - MSD 6AL
Dist - MSD Pro
Converter - TCI
Gear - .488 ratio posi
Tires - Hoosier 29x10x15

The car has been run a good bit and seems to be a 7.15 car with what I have. I have a few options, so I wanted to see what you think.

I have a set of Edelbrock E-Street Heads, closed chambered 75cc that I was putting on another car. These would save some weight, and I would have to go to the 2" headers. Would these heads & bigger headers get me to 6.9-7.0, or do I need to do something different?

I am also considering going to Hoosier radials instead of my current bias tires. Anyone make this swap pick up any ET?

I also have a .456 gear spool I could slide in vs. the .488.

Any other suggestions on how to get a quick and easy 20-25 HP?

here is a bump for you.
way back in my NU-BE days, we thought the trick to quick times was 4:88, 5:13, and 5:38 gears, no matter the tire size. well, 10.00, 11.00, and 12.00 x 15 were the tire sizes normally in use.
anyway, fast forward to the last time i had my charger out, [2006-2007, then back in storage it went] i dumped the 5:38's and installed 3:91's.
the engine was not touched other than fresh gas and new plugs.
it went within 1 tenth of the 5:38's best time.
not sure what that means, but you might want to try your 4:56's or maybe even 4:30's.
the heads and headers you mentioned couldn't hurt. i would certainly give them a try if it were me, and i don't know anything..........

Thanks Bob. Talking to Hoosier they seem to think for bracket racing the bias tires are better than the radials, more consistent and last longer. When I stopped racing 10 years ago, this car was way better than the driver at consistency!

I like the idea of bigger/better headers. Get the 2 in headman hustlers. I have them on my car and with iron heads and a 509 cam , 750 double pumper it was running 7.0's 2 weeks ago. I also run 4.56 with a 31 inch tire. I believe those headers are .1 to .15 better than any others out there.

Being your running I'm assuming 1/8th mile that 4.88 should be fine. If you were to run 1/4 mile they might be a bit much.

What stall is your convertor?
Do you know the current chamber size of your 906 heads? The Edelbrock should be right around 50lbs lighter for the pair. If their camber is smaller than your 906 than that will gain you a little compression as well.

i think CAB has said for years, 2" headers work way better than 1 3/4 or 1 7/8".
[if and] when i get my charger going again, i have a set of 2" to 2 1/8" step TTI headers i'm going to use on my 446. it has ported RPM's, 11:1 compression, and .590 purple cam, with a 4500 converter.
the car has 3:91's in it now, but i may step up to 4:10's or 4:30's, depending on what size tire i go with.
i'm hoping that combination might make my car a fun ride, even though it weighs a bunch.

I believe the converter is a 3500 stall. The chamber of the 906 has not been altered, so I assume since they are open chamber, there would be some compression gain with the Edelbrocks. The flow of the906 is probably close to the stock Edelbrocks since these were professionally ported. You are correct the two areas I think heads would help is more compression and lighter weight.
I just run the 1/8th, and getting a consistent 7.0 is fast enough for me. Any faster and I will start breaking everything behind the motor. Dad ran 6.65 with a hotter 440 and we broke everything from the engine back!

The other thing I am considering is simply swapping the cam for a slightly bigger one. I know that can be a rabbit hole, but I am probably running more carb than I need now, so a little bigger cam might get me there.

Thanks for the input.

3120 is light for a '70 RR, seems to me, so I'll guess it's had a weight-reduction program.
Otherwise, 150 fewer lbs should get close to target.
What's the tire diameter, what shift & trap RPM, what 60', what stall ?
The Eddys should flow better, any porting on the iron heads or Eddys ?
Agree on the headers.

I hear mixed messages on headers. I have to believe 2" is better than 1 7/8, however that is not the cheapest option as most 2" headers cost close to $1000 or more. Seems like a cam swap could be done for less.

If I change to the Eddy heads, I will have to go with the bigger headers anyway since they have angled plugs and you can not get a plug in with smaller headers on it.

Thanks for your input and suggestion. I will let everyone know what I end up going with and how I eventually get there.

What TeamG intake are you running 4150 or Dominator?

This car is a race car and I cut a lot out of it years ago. Doors have been cut, glass in doors remove and Lexan installed, hood and trunk supports all have been removed, so the 3120 is legit, but I can not remember if it included me as a drive or not! I need to get it weighed again, since that weight was in 2001. I have done more to the car since, including putting an aluminum water pump and housing.Not much left to reduce unless I start buying a lot of fiberglass. Only running about a 1.5 gallon fuel tank!


1/8th mile trap speed - 96 mph
60' - avg 1.63 min 1.51
Shift at 5800 rpm
Rev Limit at 6400 so I never go this high
Usually the shift light is on when I go through the finish line, so I would say I am hitting 5900-6000 rpm at the line.

I am running the dominator Weiand Team G, not the 4150. I also have two spacers, each about 1" below the carb.

Most 906 heads are 81 cc and eddys can be bought with diff CC. but most likely are 84 cc

Radials...and going a size or two smaller (a 7.15 car doesn't need a 10" tire) may put you there.

Do you have E85 in your area?

The Eddys I bought are the closed chamber 75cc. Bought them for that reason.

We do have E-85 here.

So you think going with a 9" radial would pick up the ET?

The 906s I had were 91cc. A solid FT might get you there. A good 4200 convertor wouldn't hurt. To bad you couldn't snag a 557 or 528 cam and lifter package they offered a few years ago for 200 bucks from Jegs. It would be nice cheap experiment.

The 557 cam is the one I was looking at. I figured the 528 would not be much different than what I have now @525.
Cams are kind of hard to come by these days.

I bought the 557 and the 590 both with lifters for 400 bucks about 7 years ago. I know the 528 has an outrageous price. What's the 557 going for? My car ran 11.41 @117 with the 557 and a 3800 T/A with 3.91s and 9 in ET streets. TorkerII intake and 950 Holley.
Put the 590 in it and it went 11.28 @ 119.

The 557 is about 251 @ .050 if I recall so only about 3 degrees bigger in duration, not that the increase in lift doesn't help too. If you are going to make the effort for a cam change, I would think you might want something a tad bigger. I have heard mixed reviews on the Team G and that some had some core shift. That might be an easy change if you could snag a used intake.