I have been considering building a mild drag race C5 or C6 but it would appear that one of the major problems is the automatic transmission. And will NOT run a manual at the track. Neither the 4L60 or the 6L80 are very good options. Not to mention the inconvenience of dropping the back end to service either the trans or converter.

Since I used to own a C4 and they are super cheap to buy and have the conventional engine/transmission layout, I started to think about building one with a turbo 400.

No longer a fan of the old style smallblock and so a LS engine swap would be required.

I have done LS swaps in Chevelle and Nova body's which are very easy.

Not so sure about the C4 models. Anyone out there have any advice on doing this swap?

With the big front end that lifts out of the way, looks to be easier to work on too.

 

If you aren't concerned about factory gauges, hvac and cruise control, the swap is really easy and straight forward.

There are easily obtainable engine mounts and several different 1-3/4" to 1-7/8" long tube headers that will fit with small tweaks.

Working on one is really easy too. I can swap spark plugs in about 15-20 minutes. My LS C4 is the easiest to work on hot rod that I have ever owned. The only real trouble it has given me was removing the ~10 o'clock bellhousing bolt during a clutch swap. I remedied that issue with a socket head bolt.

The only real fabbing involved will be the th400 tailshaft to c-beam mount and getting a drive shaft. You will likely need to look into a d36 to d44 swap too if you don't buy a manual car to start with.

What will be your plan? N/A, nitrous or boost?

If N/A I would suggest an aluminum block L92 6.2L and save an additional 100lbs off the nose. Throw in a big cam, LS3 intake and a free flowing exhaust and it will be in the 470 rwhp area like the modded c6 cars.

 

LS Swap is as easy as any other chassis for what you are talking about. The difficulties start with keeping the A/C/Power Steering, Gage functionality... well you know the otherwise stock appearance. Otherwise it is a hole for a SBC and an LS will drop right in. I do believe there are mounts readily available, but don't quote me on that. There are a handful on here with an LS swapped in. The Karts being touted as very simple.

 

Power steering isn't an issue if you use the c5 accessory drive, c5 pump and stock c5 hose.

 

If you are building a race car you don't need the creature comforts so an LS swap is pretty easy. I think you will need to fab up a C-beam mount to use a TH400 in a C4.

I would also consider putting a solid axle in the back too, it is not going to hook real well with the IRS.

 

Agreed, but at that point, you're likely better off starting with a solid rear platform like f body or Mustang.

 

This. I never understood why some people will get a corvette which is made to handle and drag race it. To each their own.

 

Totally agree with the F body platform over the C4 Corvette. Some really nasty Camaros and Firebirds out there.

 

Fair comment. Have been down the big tire, solid axle, cars full of pipe path already. Been there done that. Just want to have a nice street car that is comfortable with all the amenities of a street car and can still get down the track pretty quick. GM guy so Mustangs, etc are not an option.

I initially looked at newer style Camaros (which are IRS too) to take advantage of the NHRA no bar rule for 2008 and up cars. I talked to a few people with Camaros that could run in the 9's and weight was a huge factor in breakage plus you needed to make a lot of power. Well over 4000 lbs if you keep the car with all the bells and whistles.

Corvettes of C5/C6 vintage are relatively light at 3250 lbs. I think there is almost a thousand pound weight difference which equates to a second in ET and less breakage problems. Plus I happen to like the Corvette looks and seating. Also want to build reliability because of tedious major component access.

I know that NHRA rules are pretty restrictive on IRS. I don't have any aspirations of anything quicker than 10's so don't see that as a big issue. There are lots of Vettes that will 60 ft in the 1.4x range on small drag radials which is decent for a 10 second street car. Definitely no trans brake racing with the IRS.

 

C4s are light, cheap and aerodynamic. Yea, they have some short comings in the rear end department but so do the solid axle cars mentioned in this thread. Any of them making big power are going to need some upgrades or even complete aftermarket swaps to run 9s-10s without breaking.

I love my 6.0 C4, it hangs right with stock Gen 6 ZL1s and outruns stock and bolt-on Gen 5 ZL1s. The ZL1s have 100-150 more whp than I do but my car weighs 3200-3250lbs with my 215lb self in the seat. It is all about that weight difference and the tiny frontal area and short total height of the C4. It looks so little parked next to new Camaros and Mustangs.

It is quite a bit of fun taking it to the Dallas meets and surprising the heck out of guys after some runs. It isn't the fastest thing in the world but it is quick enough to hang and/or beat lots of the newer heavier cars in the 500-600 rwhp range. It is often thought of by the guys as the slowest car there and on some nights it ends up being the fastest. A buddy I met at the meets nicknamed my car the "Heart-Breaker" because it is a krusty beater that gets a ton of unsuspecting kills.

I wanted to be different and my M.O. for the past 15 years has been sleeper cars. Not many folks suspect a C4 to be quicker on the street than their $40k-$100k new car so it makes for a lot of fun.

 

C4's are relatively rare at the track compared to the run of the mill F-body or Mustang. Mine has beat more than it's share over the years.

 

My eyes ain’t what they used to be but are those C5 taillights?

 

Yup. Got a C5 butt

 

C4s look great with some rubber under the rear and skinnies up front.
May just toss my welds on this 88 Im picking up just to cruise around. Posermobile! lol

 

Sometimes I just shake my head at how unknowing most people still actively posting here......

The C4 is a very good platform for a drag car. It dosen't take much to run 10s and be reliable. I did it for years with my 84.... nothing but a pump gas 427 SBC, a TH350 with a 4000 PTC converter and D44 rear swap. Mid 10s@125mh, 1.42 60fts like nothing. The car didn't even feel fast.

I also never broke anything in 2yrs of racing and the car in that trim. It still had the stock 100K mile suspension, shocks and even the stock ujoints under it. I never had any trouble making the stock IRS work well down into mid 8s@150+mph..... Yes you read that correctly..... I ractually ran a best of 8.60@154mph and a best ever 1.26 60ft on the stock C4 IRS. I started having reliably issues with the D44 posi and 1350 ujoints in the mid to low 9s.... I fixed the D44 with a spool and just got really good at swapping ujoints as needed.

Search my posts going back a few years.... I have responded numerous times to other CF members wanting to drag race. I cover everything I did suspension wise, springs, shocks, bump stops, how a 9" output shaft TH350 can bolt right in the C4 with an inexpensive tail housing spacer..... FYI my old D44 IRS is under a CF members car and he has been running low 10s for the past 4yrs with no problem..... just finished him a new engine that's going to put him in the 8s next season.

Will

 

Will, you are an inspiration to this forum and a wealth of knowledge.

 

Willie, I appreciate that. I don't post here very much anymore.... seems FB groups and other social media are better ways to connect with people interested in the Automotive and racing scene.

I have always tried to help folks here. Shown many C4 builds I have done here and never held back important information over the years. I try to not be snide but its just plain wrong for people to that say the IRS won't hook.... quite the opposite. Properly set up it hooks so well, it won't live once you put real serious power to it. It also won't live being set up wrong.... You know that and that's why your C4 has a 12 bolt.... same reason mine now has a 9".

But for what the OP wants to do, he'd be fine with a D44 IRS using the right suspension set up, gearing and tq conerter. Espc considering the cost to convert the rear to a straight axle.
Will

 

Will,

Perfect......Just what I was looking for.

Thank you for sharing!

Now the search begins for the car!