Chevelle wheel hop

Hey guys!!! I have a 68 Chevelle, street/strip car with a 406 sbc and a 4-speed and 12 bolt rear. I have added rear poly bushings and boxed the controll arms and have the "No Hop" bars (they raise the mounting point for the upper control arms and have solid bushings). I have run these no hp bars for years with my old tired 350 and they worked great, with slicks they make the rear suspension seperarte and, in therory, plant the rear tires, now with the 406 the car either bogs bad or spins. I have tryied all kinds of different things to remady this problem and nothing seems to help. recently I decided I was going to remove the "No Hop" bars and install poly bushing back into the top ears of the axle housing. My thought was that I will change the angle of the upper control arms back to stock and change the instant center, so as to not hit the tires so hard, maybe take some of the shock away. so I did that this week end, went out on the street, dumped the clutch at 2000 rpm and wheel hopped like a mad man!!!! WHAT THE HELL!!! so I tryied to do a burnout, HOLY CRAP!!! even worse!!! My question is WHY??? every one I talk to says that poly bushings solved there wheel hop problem. It should all be pretty solid back there!!! Also being Im asking, say I had no wheel hop problem, is my thinking correct?? Would this help? Thanks guys for letting me ramble!!!

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Originally Posted by GUS68

Hey guys!!! I have a 68 Chevelle, street/strip car with a 406 sbc and a 4-speed and 12 bolt rear. I have added rear poly bushings and boxed the control arms and have the "No Hop" bars (they raise the mounting point for the upper control arms and have solid bushings). I have run these no hp bars for years with my old tired 350 and they worked great, with slicks they make the rear suspension separate and, in theory, plant the rear tires

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Let me be the first to welcome you to the “tech” portion of this wonderful board. You are correct that the no-hop bars are designed to help traction woes by increasing the anti-squat characteristics through decreasing SVSA of the rear control arms. This is great for ¼ mile action, sucks for just about anything else.

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Originally Posted by GUS68

I decided I was going to remove the "No Hop" bars and install poly bushing back into the top ears of the axle housing. My thought was that I will change the angle of the upper control arms back to stock and change the instant center, so as to not hit the tires so hard, maybe take some of the shock away.

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I see by your post that you have discovered that poly bushings are NOT the cure all for suspension woes. They actually do not solve anything, but instead cover up some poor design geometry and in some cases “seem” to make things better. All you are doing is increasing rear stiffness and in affect increasing rear spring rate having the same affect as raising the rear arms to increase A/S. You take some of the hit away by softer shocks or leaving with less RPM.

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Originally Posted by GUS68

My question is WHY??? Every one I talk to says that poly bushings solved there wheel hop problem. It should all be pretty solid back there

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I’m guessing that you are talking with the local “bench racing experts”; you will find that most of these guys no very little if anything about suspension design. I would suggest looking into some Wolfe Race Craft pieces or building your own links. Polyurethane has it’s place in the suspension world…just not under the back of an “A” body.

Hey thanks for the response!!! The people I have talked to are people I know that go drag racing with me. One freind of mine has a 69 chevelle that runs low 12s and high 11s, he has poly bushings and old stock shocks and some "overload" springs. I also talked to a guy with a 69 chevelle that was running low 9s!!! with a big block , I asked him about his suspension, he said he had poly bushings, stock springs and the shocks were on the car when he got it. that car would pull the front wheels about 4ft in the air!!! The only exception is that the people I talk to are all running automatics, so I would im agine its not such a hit to the tires.

You should try the Jeg's Lift Bars. I think they're about $180 for the pair. Most of the 1/4 mile guys on Team Chevelle have had good luck with them. I have them on my car but mine is too mild to really be a good example. I've never experienced any hop.