69 chevelle pro street project

**Dave Severson** · 02-24-2014 02:58 PM

QA1 are street rod coilovers and not even close to being the best for a drag car....AFCO's or Koni's are the way to go if you want a shock that actually works!!!! You aren't even close to picking gear ratio's or tire sizes yet, don't let the cart drag the horse around! Gears and tires are decided by the engine you're running, the RPM you want to turn the engine to keep the power up, what transmission you're running and a myriad of other things!

What "front section" are you referring to, body panels or suspension?

**tylerj** · 02-25-2014 07:24 PM

I guess what would be recommended for a pro street car? Something that could be used for drag week etc.

I don't know if your familiar with Larry Larson's Chevy II. I am looking to build something very similar to that just not quite to that extreme.

Thanks Dave.

**Dave Severson** · 02-26-2014 07:25 AM

Larson's car is an all out, full tube chassis drag car that can and does do a great job on the street! Like the Lutz cars and the rest of them they are very mega-buck purpose built cars....

"The look" can come from spending less money, just realize up front that the level of performance these cars attain and still participate in drag week and other such events is a 6 figure undertaking!!!! Us common folk have to settle for a little less--a car with a back half chassis, LS and a supercharger, nitrous, or a single turbo can consistently and (somewhat) reliably run in the mid 9's and still maintain some semblance of street manners... I'm doing a rebuild on a friends car right now that has a long history of street and some drag performance. Once it had a 632" BBC with a 2 stage nitrous system and went a best of 7.90...now it will be a mild mannered 540" BBC and a single shot (max of 200) nitrous and probably do low to mid 10's and be "competitive" even in street trim---though somewhat slower.... The car is a '69 Cutlass, same as your Chevelle (other then some sheet metal) and if you're willing to do the work and spend the $$$$$ you could expect the same... Be warned, though!!!! The Cutlass is just a rebuild, most all the good parts were already there before. I'm doing the car for only enough to cover materials and utilities but even at that the bill is well in excess of $10K not counting the engine and driveline!!!! If I still had my big shop and was paying my help and overhead the bill would be at least double that.....

You're probably already tired of me stressing the money involved in this kind of build. Reason is I've seen far too many people come into a project like this all fired up, then run out of $$$$$, time, patience and often all of the above when the project is about half done!!!!! Anybody can go fast, just depends on how fast you can afford to go!!! My first best advice would be too set up a budget of how much you can REALISTICALLY afford to spend on the project, and what kind of time frame you're looking at from start to completion! Also, there are two definite rules that apply to a Pro Street, Drag Car, Street Rod, Restoration or any other kind of build:

1. It's going to take longer then you thought.
2. It's going to cost more then you thought.

With that in mind, it's time for you to set up some realistic plans for the car and figure out a budget for it, IE $XXXX dollars for the chassis, $XXXX dollars for the engine, $XXXX dollars for the driveline, and $XXXX dollars for paint, interior, and cosmetics.....

Just some advice from a guy that's been playing these games for way too many years!!!!!!!

**tylerj** · 02-26-2014 12:03 PM

Alright maybe Larson's chevy wasn't the best example but what I'm looking at on his car is how he set his suspension up for the street but also being able to handle his launch at the line. I am not wanting to go all out as he did but I would like to build a step or two down from that. Such as I would like to stay away from the tubular chassis.

As far as starting this and not being able to finish it; it's more than just money to me.. Working on cars and learning what you can do with them is much more than a hobby to me, it is something I can come home from work and be excited to work on. That's why I call it a project, I have no time limit as to when I want it finished nor the total expense. I will however work on it tell it's done, I really don't like starting things and not finishing them.

A project like this I do not plan on sparing any expense; I want to build a car completely and I don't want anything done and have to wonder if it will hold up.

**rspears** · 02-26-2014 12:43 PM

The most critical part of any build project is planning the build, first at an overview level, and then getting down to details about what you want in order to get it to the end. Once you have a plan in place, the next most important part is following you plan, and not heading off down rabbit trails that end up driving you to make major changes to work already done, or spending 10X what you planned in a given area. Planning your work, then working your plan gets you to a satisfying end result. Having an unlimited budget and no fixed end date should make planning a lot easier.

**Dave Severson** · 02-26-2014 02:22 PM

Ok, here's some pics of the Cutlass. It's a back-halved car with a 10 point cage, front suspension is stock other then light weight springs and Koni drag shocks. The frame is stock GM from the ladder bar crossmember forward, rear frame is 2" X 3" rectangular tubing. Wheel tubs, trunk floor, interior panels are built from 20 ga. The back is a Dana 60 differential with ladder bars, coil overs, and a panhard bar. The dash, gauge cluster, and console are custom built.

Is this something along the lines of what you're contemplating??????

**pro70z28** · 02-26-2014 04:19 PM

**tylerj** · 02-26-2014 11:18 PM

Dave, That cutlass is very similar to what I am wanting to build. What is the potential completion plan for that car? Street strip?

For a car to be certified to run 8.5 and slower do you need a 25.x cert chassis?

And Pro70 that looks like an awesome project, Looks like you have came a long way on it. I am also very glad you're not giving up as well, gives me more and more hope. What is the time a car like that is certified for?

Thanks!!

**Dave Severson** · 02-27-2014 03:08 AM

The Cutlass is moving into "semi-retirement" and will be just a street cruizer. Long story behind the car.... Depends on where you're running, but yes the correct answer is to say the car has to be certified by NHRA to run 8.50's. Some tracks have an inspection day prior to the season starting to get the car certified. Pro Z went through the whole procedure on his 'maro and posted it on his build thread. If you check on the NHRA web site it has the information on how to get the build information and criteria that the car must meet to be certified for different ET's....

**tylerj** · 03-02-2014 09:32 PM

Alright I am having a hell of a time finding build requirements for ET's. All I found on there was a quick reference chart saying yes or no for different areas. All it says is for a 7.50-9.99 second car it needs: driveshaft loop, NHRA chassis sticker, roll cage but it doesn't say if there are any other chassis requirements for 8.50-9.99.

I did find else where in the book that a 10 pt cage with swing out door bars are permitted for 8.5 and slower. But I will double check with NHRA to make sure nothing on the chassis needs to be added.

But aside from that, setting up the car its self... I am just trying to get some ideas and amounts on paper. For the chassis I was thinking:
-26" rear frame section
- Double adjustable ladder bars (still unsure if I should use ladder or 4-link)
- diagonal link
- Double adjustable coil overs in the rear (unsure of a brand)
- drive shaft loop
- springs (unsure of spring rate)
- fab narrowed 9 inch
For the rear

Something like that sound reasonable?

**Dave Severson** · 03-03-2014 06:10 AM

You need to order the entire SFI spec sheet from NHRA, or find someone who has it.. A car the size and weight of a Chevelle need a 4" or 5" stroke shock, which for me makes AFCO the shock of choice. AFCO's can also me mounted inverted, which lowers unsprung weight. I've also used Koni's and Strange, all good shocks. A four link would be the preferred suspension, though a quality ladder bar setup works equally well on the track in a car like this. If you're going to be on the street, then I'd suggest a Watt's linkage instead of the diagonal link. Don't worry about spring rates now, you need the car put together and put on a set of scales to figure out the correct rate. When you decide what coilover to run, you'll want to build or buy a solid link in the coilover's position, set at ride height, to have in the car while you build. What you do need to have before you start setting frame rail width and height is the tire and wheel combination you'll be running, this eliminates all the calculating and guessing on where and at what height things should be...

**jerry clayton** · 03-03-2014 09:44 AM

If you can get a Moroso CompetitionEngineering Catoloque there is a lot of info in the back of it about different types of suspension and all the way thru specific packages for certain cars---------

**tylerj** · 03-03-2014 01:59 PM

I will definitely get a hold of one of those then. I am a little rusty on racing suspension Jerry so I am taking as many resources as I can!

How do I decide what tire size to run? I know in someone else's post Dave actually commented on something saying people make the biggest mistake putting too large of tires on a car when they don't need them. However, a car that I am working towards building will be a street car, and a lot more power hitting the tires so I assume I'll need a little larger tires to compensate for the higher hp. Just looking around at other cars similar to what I'm shooting for I am seeing anywhere from 29" tall through 31" tall and 15" wide through 19" running either 4:11 or 4:88 for the rear. I know picking a tire size will somewhat determine what gear ratio will be used. But what bases your tire size?

**rspears** · 03-03-2014 03:35 PM

Tyler, for a street/strip car I'd say that your tire height is going to be driven more by appearance than anything else, and then you may have a set wheels & tires for competition. To get into the quick times you're targeting I expect that you're going to end up with some very tall rear gears, so you might want to consider a Gear Vendors OD unit to give you some street manners. Your cruise rpm is affected by your tire diameter, rear gear ratio, and final tranny drive (OD) ratio. Once you have your basics set you can make a couple of test runs to see where you are going through the traps, and maybe use your competition tire diameter as the final variable to dial in your gear/rpm to optimum.

**tylerj** · 03-03-2014 03:49 PM

yes, so the bigger the tire the higher the RPM will have to run to turn the bigger tires. But the gear vendors OD has been an idea depending on tire size and gearing.

I was planning on a built TH400 as far as a tranny, The motor itself will hopefully just be a beefed up LS BBC with twin turbo to keep it streetable. But how do you decide a base front and rear tire?

Once I figure tire size I suppose that will tell me how narrow to go with the axle, frame, and if I need to get drop spindles or springs.

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