Hey Dave, I want your opinion on front/rear %...

For my truck. We scaled it last weekend with me in the truck, but without some engine parts. I figure we are 100-150 lbs light on the nose still. It weighed 2165 with 48.6 on the rear. I suspect it will drop to 45% when it's all said and done and weigh about 2350. I have a way to move about 40-50 lbs to the rear for about $400. What do you think?

Thanks,
David Willingham

I'm sure you have mentioned it in the past but what did the finished wheelbase end up being, and the crank nose height off the ground?

Having a nose heavy front/rear of 55/45 by it's self probably isn't really a big deal since your using a 4-link. And when you think about it 55/45 isn't really that nose heavy even with the long wheelbase when compared to where some cars are sitting at. I guess it will really depend on how much actual launch power/torque you will have to work with.

I do know when a friend bought an ex Pro Stock truck motor & trans from a former racer the guy was kinda tight lipped on the subject of weight percentages & 4-link settings used on their truck. He did admit (for their truck anyway) that what was thought of as "normal" 4-link thinking didn't work in the PST class, and they had to allow a lot more tire rotation at the hit. But I later got to wondering if his statement didn't really have less to do with the weight percentages, or the long wheelbase........and more to do with the fact that these tiny motors just really don't have any big/wide torque curves to work with. And it's a good bet that your going to have some very usable launch torque numbers to work with.

I guess the smart thing to do would be to make any weight you add/move as removable ballast and not permanent ballast. Making hollow weight bar(s) and a hand full of mounting tabs won't be too expensive.......but the lead shot for the bars probably will be. Even used lead shot from a scrap yard can be kinda pricey these days.

Wheelbase is 115" and the crank is 15.25" IIRC. I'm moving the fuel cell to the rear and using a cable drive for the fuel pump. That will move 40-50 lbs to the rear.

I guess a rear mounted cell might not be a problem for an injected engine. But if you were going with a nitrous/gas or blown/alcohol setup I would probably say stick with a front mounted cell.

At about 15" off the ground that sounds like about the max I would ever want to see a big engine sit in a modern full chassis car. But on the other hand at that height there might be a side benefit in helping to offset any nose weight bias during the launch.

It's too bad that the chassis is already done. If you were still building the basic structure you could shift the front/rear bias a decent amount by shortening the bed & stretching the nose a little.

The engine may be a little lower, it's been years since I measured it. I have done everything possible except modify the body panels to get weight to the rear. The front wheels have been moved forward as wheel as the rear. The engine is back as far as possible. An aluminum block would be nice, lol. "Call the man Aunt Bee, just call the man".