The Dodge Challenger Message Board

Hi!
This is some pics of my Challenger...
I am a new member at this wonderful site! And i have so many ideas and QUESTIONS that i am curios about, so i hope that i can find help and information here... (Thanks Roland for the tip =)
This car was shipped to Sweden in -87 and was restorated, painted to this condition about 10 years ago, by previous owner... It is an matching nr car with 340 engine, torqflite 727 and 8 3/4 rear end with 3.23 gear...
Its running fine but, as always there are things that needs to be fixed, or that i want to change...

I have some problems with finding specs for the engine restoration. The only thing i know is that the engine is built up with forged pistons and another cam than original. plus headders... and a Holley 650 on the original intake manifold... i also think that i have cylinder heads from an 360(?)
I am curios about wich type of cam i should pic if i want to get some more power and i am also curios about wich type of converter i should choose and if it is necessary to switch the gear in the rear axle???

Best regards, Jim

Your car got here before you did ( http://challenger.mpoli.fi/forum/viewto ... 3258#23258 ), but you probably already knew that, didn´t you?

Welcome to the board!

Hello Jim and welcome to the Board,
thanks for your visit on my homepage and the complimet !!

Your challenger looks also very very good!!
Likes me really well in Black...... nice colour

Yes, I got told by Roland that the picture was here... =)
Very nice

Jimiboy wrote:It is an matching nr car with 340 engine, torqflite 727 and 8 3/4 rear end with 3.23 gear...
Its running fine but, as always there are things that needs to be fixed, or that i want to change...

I have some problems with finding specs for the engine restoration. The only thing i know is that the engine is built up with forged pistons and another cam than original. plus headders... and a Holley 650 on the original intake manifold... i also think that i have cylinder heads from an 360(?)
I am curios about wich type of cam i should pic if i want to get some more power and i am also curios about wich type of converter i should choose and if it is necessary to switch the gear in the rear axle???

Camshaft: I would call it The main choise when you build an engine....Most of us want to build dual duty cars, i.e. street/strip-cars. The most important consideration is how much of the low rpm torque you are willing to sacrifice? If you ask me, one of the main advantages with a V8 engine is that you get a lot of low rpm torque compared to most non turbocharged four-bangers for instance. Jump on the throttle and you get a lot of neck-snapping acceleration even at low rpm:s. I don´t want to loose all of these pro:s myself if I would choose an aggresive cam profile. Yes, I can sacrifice a little but not all of it. How do you want your car to act on the street? How do you intend to use your car? I hope you get the picture.

Thanks to Mother Mopars wide diameter lifters (on ALL mopar engines, right?, I am not 100% sure) you can use camshafts with an agressive cam lobe, that is a very sticky cam. Hughes Engines (they have a very informative web site) sell such cams for instance. Some of the guys seems to like them and others don´t. My recommendations are that if you choose between a milder and a wilder cam, I would recommend you to choolse the milder cam. Why? I guess it happens quite frequently that people end up with too much camshaft. I think it happens more frequently than the other way around. Another recommendation is that you choose a cam with "a little more lift/a little less duration" compared to a cam with "a little less lift/a little more duration" (two similar camshafts). You with get more streetable power (more hp at lower rpm) that way.

How would I do? I think I would start from scratch with a bare block and build a stroker small-block for instance. If you sell your engine (if its not a number match of course), you will probably get a good start capital. Just a suggestion...

One last thing: It is a good idea to examinate your existing cam. To measure how muh it lifts is quite easy if you measure on the rockers. It may give you a hint about what profile your cam has. To get information about the duration is a bit trickier though.

Converter: Most of the guys here seems to be using converters with a stall speed of about 3000 rpm, so I suggest that you opt for something similar. The main consideration is to NOT choose a converter with a stall-speed higher than of your intake/camshaft-combo....

Gear ratio: To choose a 3.91:1 ratio will give better acceleration if you can get all the torque down to the pavement. On the other hand it will give your car annoying high rpm:s on the highway (unless you use an overdrive or a five-speed of course) and you will get low milage. 3.55:1 is the best compromise if you ask me. They seem to be quite hard to acquire though (quite rare and expensive...).

Good luck!

Btw: Try to use the search feature of this Message Board. I am sure you will get a lot of information that way.

Cheers
Chris

The main power comes from two main things. Engine volume and cylinder heads.

For example it is no good having an engine that can pump a large amount of air/fuel if the heads are not capable of flowing that much.

So you have to decide what your max rpm will be and make sure you have head ports/valves that will just flow that amount. Heads that are too big will kill performance at lower rpms.

Then you need to select a cam that matches the rpm range of the heads.

Then you need to select an intake manifold that works in the same rpm range as the cam.

Then you select a rear gear and tyre size that allows you to drive in the rpm range the cam makes the power. I usually select a rear gear that makes the car drive at 70mph (or whatever your highway cruise speed is) at the same rpm as the engine is making peak torque.

Then you need to select a torque converter that matches the duration of the cam, weight of the car and rear axle gear.

When it comes to performance it is better to have slightly more stall speed than you need. But the trans will run hotter and fuel economy will suffer.

But ideally you will select one that is ideal and the car will drive normally without you having to raise the rpms much to drive away or without you having to stand on the brake hard to stop the car driving at idle.