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67 Chevelle twin turbo winter revamp and car history
I don't think I've done a build thread on here, but I've certainly saved a ton of ideas and have learned much from others. My main reason for posting is the hope that someone else may benefit from some things I have done or apply their own twist to an idea.
This might is long winded, but it's a good foundation for where I've gotten to, or skip to photos with what I'm working on with the updates
The LS bug bit me about four years ago when a buddy of mine had recently finished up a 5.3 turbo setup in his Nova. Not that it was my first turbo rodeo, I had another 67 Chevelle with a single turbo and traditional small block. I had walked away from racing for awhile, but something about seeing that 5.3 run 9's was really cool. So I picked up another Chevelle, which had a Sahfiroff 540 in it, offed the 540 shortly after getting the car home, and jumped into the LS coolaid. The build ended up being a multi purpose drive it build and I also did Ridetech pro touring suspension so I could drive the hell out of it.
I battled some bugs for almost two years trying to get things to come together, and went through several combos. A 370 with twin BW 366's, then a 408 with twin turbonetic 66's, and eventually sold everything off to build new from the firewall forward to fix what ever it was that was holding me back. Best I could get out of the car with Ridetech pro touring suspension was 9.6ish. This was summer 2015
Fall of 2015 I decided to pick up a 67 Nova with a 434 and twin Precision 72's that would be a more serious street/strip car. After a nice winter of fixing under dash wiring mess and rebuilding the turbos, I raced it first part of 2016, car went 8.75 at 158 with a 1.55 60ft. I didn't get much seat time to work out the leave. I decided to part ways with the car in May of 2016 and focus on making my Chevelle fast. Evidently I like the punishment of trying to make heavy cars fast.
So I kicked off a build for a LSX 427 with Brodix BR7 heads and flipped some C6 manifolds and did some Precision 6766's. Right out of the gate I still had issues that plagued me with my other combos. Anything more that 6-8lbs of boost and it wouldn't run. Funny, the car ran 9.7ish or so on the springs. The car wasn't going to hook on the Ridetech setup Car was also on E85. I also went with a Shearer A/W intercooler.
That winter I ditched the Ridetech and went all out with TRZ suspension and put a 3.25 rear gear in the car. My mistake on not sending the converter in, so all of my 2017 year was about 11-12% slip at big end.
Start of 2017 I picked back up with my engine issues. I swapped out injectors, still had problems. Where things finally turned the corner was discovering the stock truck coils, coils I used from day 1 on my LS build, were bad. I purchased the Holley branded smart coils and Holley harness, and bam, it all came together, first pass out of the gate was an 8.99 without touching a thing. I think this was mid April 2017. April at the Westcoast Shootout race in Woodburn, I picked up a bit more and went 8.75. I didn't have a handle on suspension yet, and we were pulling an extra 12 degrees of timing at the hit and ramping back in over 1.5 seconds. Total timing in boost was 14 degrees during this time and I think I was around 20lbs. After watching some vids and getting feedback, it was clear the suspension needed some adjustment, my anti squat was out of whack at 240%. After making some changes, the best I could get was 165-170%.
In May I took the car to Bakersfield, CA for a 2nd Westcoast Shootout race. The track officials took to my car and gave me great feedback. I started to really play with shock settings and the timing at the hit and ramp back in. 3rd pass I nailed an 8.49 @ 169 with a 1.369 60'. I backed that up with a 8.52. Boost at this point was 25lbs for most of the run, and 30 for about the last two seconds.
July I took out the 2nd gear sprag, 2nd time since owning the car. It's what I get for having a stock TH400 and abusing it.
After getting the car back out in August, I focused on 60', but could never get it to come around like I wanted. I still had to pull a ton of timing at the hit, and could only leave at 3300 and about 2lbs of boost. With a fresh trans and less boost, I squeeked out a 8.42 @ 167 with a 1.39 60' The car had some tire shake, otherwise I think it would have been that 8.3ish pass that I hoped for. I also had several high 8.4 passes. That pretty much ended 2017.
Before I go into the updates, Here are photos of the car and the time slips from 2017.
Full stock interior for comfort
Last edited by GotBoostRacing; 02-07-2018 at 02:07 AM.
Some shots from previous suspension upgrades and how I've mounted some things.
I ran out of pump early on in 2017 and added a second 12-1800. I know a lot of people don't like them, but so far it's worked out. The big thing is how quiet they are. 2nd pump set comes on at 5lbs. I might consider switching it up in the future.
The rear chute frame slides into the main frame, then I have a 1/2" grade 8 bolt going through the two. It makes for easy disconnect if I want to cruise around without the chute. The cable tucks in behind the bumper. So far it's held up and was the same setup I had on my other car.
Last edited by GotBoostRacing; 02-07-2018 at 01:34 AM.
For this winter upgrades, there were a few things that I wanted to address as a Priority. Cooling, and the trans. Other upgrades were selling off the Precision 67's for something bigger, and leaving the flipped manifolds for some headers. I felt that the exhaust side was a bit choked and therefore wanted a 75mm turbine side and go from 3" exhaust to 3.5".
I didn't have much fun cruising the car around in 2017, I fought temperature issues in traffic. I had moved my fans to the front of the radiator so get clearance for the A/W intercooler placement and thought I might have an issue. The car ran fine on the freeway, it just didn't like slower traffic. The goal was to get the fan behind the radiator. In taking a hard look at the project, I discovered my radiator was damaged pretty bad from a previous head gasket loss. All the pressure feeding back into the radiator balooned all my coolant passages and all the fins in between were squeeshed together. With a drop light on one side of the radiator, you couldn't see light through. I now think that was killing me more than the fans being in front. It didn't stop me from going forward though.
With the trans, I wanted to step into something safe, reliable, and a gear change to help the car leave. I decided to go with a Rossler TH400 XHD Reid case and their 1.97 gear set. It's still going to be a 3 speed, and I wanted that setup for street driving. Believe me, I went back and forth for two months on whether to do a 2 speed TH400. The closer ratio gear set will be nice to have minimal rpm drop at the shifts. I won't have the trans for another week or two, but I'll certainly post pics up when I get it. I can't say enough about Carl Rossler, he spent an hour with me on the phone going over all the details and never tried to oversell me. He said their XD was plenty for me, but I was really after the 36 element sprag. And the converter got sent back to PTC to bring it up to speed.
First round of parts. Most of what I'm going to post up now started a week ago and I'm still in process of hacking stuff up. It's not pro, but what the hell, I do my own work.
I went with GP headers, they are 1-7/8 x 3". The hard part with Chevelles and doing an up and forward header is the steering shaft clearance. After providing some measurements, they were certain their headers would clear. I did buy a set of Stainlessworks at one point, but they hit. The only thing I don't like is how far forward they are, but I think its partly to blame for the merge collector.
I'm also going to give the tight CX racing elbow a shot since they are short. I don't really like the quick short turn radius, but I don't have much room for anything else. Waste gates will be Precision 46mm, they are pretty compact.
Quick test fit on the car and getting a rough idea on the new location for the intercooler. It was originally a side exit, and I had it changed up to the center and up exit. What became clear is that the long nose on the LS water pump had to go, it took up too much. Just look at all the room in front of the super damper.
This is where the winter build kicks into full swing, and I just started last week.
To gain some more room, I decided to get the Davies Craid setup a try. I really hated to give up power steering, but it was most important to get a nice fan behind the radiator again. The main goal here is to move the intercooler closer to the engine. This change also required a new alternator location, so I picked up another ICT billet mount and moved it to the passenger side.
The only negative item to note so far is the pump location has some interference with the Chevelle idler arm. I cut as much as I could from the hose end on the pump outlet to move it out of the way. It's only at full lock there it touches, and it's not by much. Something to take note of. Down the rode I'll probably pick up the Davies pump controller, but for now I do not have it.
Here is the idler arm just touching the backside of the housing
Always liked a 67, had a couple over the years-car def sits right, def a beautiful piece. I put my 3.5 screen same place as you, I figured it was better than past locations. They make elect. PS pumps, actually make a setup that fits in the middle of your col., not sure how that would work out, looking at that for an old early vette.
The next thing I tackled was the new intercooler location with the pump out of the way and fitting the new radiator and fan setup. A fellow LSX turbo Chevelle buddy turned me onto this really compact Derale fan/shroud setup. It's only 3" total thickness including the shroud.
What became obvious is my IC outlet to TB location being too close to each other. No way was it going to work out, so I picked up a Super Victor and Wilson elbow. After staring at it for a day, I decided not to use it.
The other thing I wasn't liking was the radiator and IC not having much distance between them and I figured there would be a negative affect on flow from the fan.
I have no idea how much I'm going to disturb an already great design on the intake, but I'm going to give it a shot. Of course proper distribution is a concern from the amount I had to remove off the front. Good news is, I was able to make an inlet.
To make the radiator/fan play well with the IC, I decided to take the lower section out of the core support so I could move the radiator forward at least 1". The radiator cap stopped me from moving it any more forward as I didn't want to take a section out in that area. Fabing up some mounts for the fan shroud was a pain, but it worked out pretty good.
A couple days ago I got the lower cold side done. I'm going to add some gussets for the angle iron mounts for the IC, it flexes a little bit.
I also got some of the downpipe tacked together. It wasn't until two days ago that my goal of getting 3.5" exhaust under the car was probably going to work. At this point I still wasn't 100% certain I'd get it snaked through the steering shaft and frame. For months I debated about dumping it out the front fenders to save some weight and make max power. In the end, I still wanted it somewhat quiet for street driving. I may build a 2nd DP set and do a dump up front just to see what the difference is.
Yesterday I tacked together the rest of the drivers side downpipe and the passenger side. For the last few days I've stared at the stock crossmember and looked for any modified photos to gain some extra ground clearance with the exhaust. I decided to just pull the trigger on a G Force crossmember and not hack up the stock one. From everything I've seen, I'm sure I'm going to tuck it up pretty tight. I'll know tomorrow or Friday.
Today I worked out the wastegate location, and while the drivers side isn't where I would like it to be, it will have to work. I think I'm going to weld an aluminum 90 out of the radiator to keep the rubber coupling away from the gate. I might add some heat shield between it and the IC as well.
Finished mounting both BOV's as well. That pretty much catches things up. I hope to have most of the hard stuff done by the end of the week. The only thing left to buy are new injectors as I maxed out my 160's.
Power wise I'm hoping for 1600ish, or what ever it takes to run a 7.80. I'm hoping for an improvement in the leave. At this level I really should step up more on the crank and rods.
Got a call from PTC today on the converter, and everything looked good from the previous couple years running it, so that's good, and they are changing the stator to tighten it up for the new combo. Now I just need my trans to ship.
Another long day in the garage to get most of the WG pipe done. I have mixed feelings about not having it uniform, but I really wanted to focus on dumping back in near the first bend in the DP. The gates are different because the passenger side was my optimal location, and I didn't have the room on the driver side to put it in the same location.
02-07-2018, 12:16 AM
67 Chevelle twin turbo winter revamp and car history 
