Mopar Muscle Association UK

3 on the tree :shock:I know Brutal has a column shift too,so you are in good company(so do I actually,but 15.5 aint worth getting excited about is it??)
Well done on what you have though,,

MilesnMiles wrote:Jeff, you ought to see the humungus and rusted bolts that hold them on. Nasty!

take em off and replace with ss ones

Rich, that's part of the fun. Getting into the 13 with a tree shifter. The trans is 727 with shift kit and it certainly bangs through.
Like I said in the write up, its on a budget so I have to select what I think will give the most back to me!
Of couse, if I fail in my ambition, i'll look like a right lemon

Brutus wrote:Don't think a stock motor will ever see 7k , the lifters will bleed down plus the heads won't flow , not to mention the valves bouncin off there seats.

You had your head out in the cold or something Brutus?

I was talking about what the stock rods and cam will take. Not what a stock engine and cam etc will do.
Obviously he isn't going to rev it to 7.5K as it is. All I am doing is telling him to stop worrying about hitting 6K.

All you are doing Adam is making him worry about stuff he does not have to worry about at his level of performance.

If he has the springs that match that cam he has, he will probably be OK up to 6.5K. But, shifting at more like 5K as he is, he is not even using anything like the full power of the engine.

Rod bolt stress has to do with piston speed and weight.
Chrysler engineers designed the rods/bolts to take 6.5K for short periods of time with the stock pistons easy.
If you are hitting 6.5K a dozen times every weekend then yes they may well eventually fail.

But a few times, once or twice a year, isn't going to hurt them.

Another factor is stroke length. The longer the stroke and the shorter the rod, the faster the piston speed. And the faster the piston has to change direction.
This, as you can imagine stresses the big end and rod bolts MUCH more.

Lighter pistons than stock however will take some of the strain off the rods. So when you fit lighter aftermarket pistons you are in effect also giving the bottom end much less work to do.

One more factor is balance. The better the balance job on the engine, the more you can rev it. This is because a smooth engine puts less stress on the parts and allows them to rotate faster with less stress.

I had a 340 Duster 4 speed as a daily driver, commuted 100 miles per day on occasions - always gave it 6k on the way home, gotta be done

Motor was pretty much rock stock.......slight cam, nowt special........

Ok, i've been wimping out. I Bananarama! harder at Portreath (15miles away) than the strips at Shakey/Santa Pod (250+miles), just down want it breaking.
Even so, the new cam will want more revs and it has the correct springs retainers etc..so advice duly noted

Yea Dave , bloomin cold out there.

If you are on monoleafs, I think you would benefit from some kind of traction aid. Cal tracs are expensive, so I think a pair of old school traction bars would stiffen the front section up a treat, cheap as chips...

Blue wrote:If you are on monoleafs, I think you would benefit from some kind of traction aid. Cal tracs are expensive, so I think a pair of old school traction bars would stiffen the front section up a treat, cheap as chips...

Any pics of the traction bars Blue?

Yep, The style with the integral spring plattform is best, or the universal type. To be honest you could make your own from a length of 2"x 1" box section. The rubber snubber needs to be directly under the front spring eye.

Blue, coud you explain what they do,please?

Thanks Blue

Yes, under hard acceleration the front section of the spring tends to get bent into a sort of S shape by torque, the spring fights against this and you lose traction as the wheel bounces up and down, sometimes accompanied by heavy juddering. This is commanly known as axle tramp.
The traction bar effectively makes the front section of the spring solid when the snubber hits, preventing this from happening. It also uses the axles rotational motion to raise the body under power to further plant the tyres. For this reason you will also find them referred to as lift bars.
Mopars do not normally suffer from this because the front spring section is short, and has multiple leafs to make it quite rigid. A monoleaf spring will not be so rigid and I would think it could use some help.

Use a correctly adjusted pinion snubber and don't touch traction bars with a barge pole.

Traction bars stop the housing rotation at the tube ends near the brgs but the pinion is trying to climb up the ring gear so the axle tubes are twisted. High torque engines with great traction can bend or even split a housing at the ends.

Mopar Performance and Mopar Action both advise against using them on a Mopar.

Here is what Mopar Performance says about traction bars.
"Traction bars are not recommended. Traction bars should NOT be used with Super Stock springs.
In many cases, the use of traction bars results in bent axle housings or other equipment and may adversely affect the car's handling."
Page 316 of the Mopar performance Chassis book.

Yes I agree Dave, but we are not talking about a high horsepower application here. Also there is no comparison between the front section of a super stock spring which has at least 6 leaves and a monoleaf. I think it's a good solution in this particular application.