My 79 Hotrod Project Build Thread - CorvetteForum - Chevrolet Corvette Forum Discussion

Notices
C3 General General C3 Corvette Discussion not covered in Tech
Sponsored by:
Sponsored by:

My 79 Hotrod Project Build Thread

Old 09-20-2017, 09:02 PM
  #1  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default My 79 Hotrod Project Build Thread

Hey guys, been meaning to do this for a long time. I thought it would be a good idea to have a build thread both to keep track of everything I've done and to be a sort of motivational tool so anytime I feel like I'm not making progress, I can look back and see how much I've done so far. Never done one of these before so here goes (if you don't care about back story, skip ahead to the next posts. I plan to upload the mods I did in order):

I was on the lookout for a project car early in 2016. I've been a car and motorcycle enthusiast my whole life, but I've never owned a really fast car (fastest I owned before this was a 350z, though my brother owned plenty that I drove fairly often: WRX, STI, GTO, SVT Cobra, etc...). I've owned a few quick bikes (CBR 600RR, SV650, Daytona 675, and my current bike: Buell XB12S). But I've always wanted to buy one of my childhood dream cars and build it up into something fast...

I grew up in the 90s, and the cars that appealed to me were mostly imports, specifically the 1993-97 RX-7 FD. I've wanted that car most of my life, but the price of entrance is a bit high for a decent stick shift one, more than I could afford anyway. I used to love the 300zx, but I owned one for about a year and pulled the engine twice for (relatively) routine maintenance and was so sick of having no room in the engine bay that I sold it.

I started thinking, what car draws my eye more than anything else, and I realized it's always the old C3 corvettes. I'm not a corvette guy, I think the C5 is ok, I find the C6 ugly, and while I like the C7, I see a couple everyday on my drive to work. Don't get me wrong, I respect the technology, engineering and performance of the late model Corvettes, but they don't appeal to me the way a C3 or C2 does.

So I started looking for C3s. My only requirements were that it was a 4-speed with little rust for cheap. That turned out to be harder to find than I thought. The only ones I found were either rust buckets that weren't worth it if I got them for free, or immaculate restored cars that the owners wanted insane money for.

Then my wife sent me a message at work and said "hey check out this C3 I found on the St. Louis craigslist, it's not the original motor, but it has a stick and looks decent!". Drove out to Saint Louis that night (about a 3 hour drive) and drove my new C3 home!








Last edited by mobird; 09-20-2017 at 09:03 PM.
mobird is online now  
The Following User Says Thank You to mobird For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 09:05 PM
  #2  
mchar
CF Senior Member
 
Member Since: Oct 2007
Location: Kensington MD
Posts: 8,653
Thanked 27 Times in 25 Posts
Default

Pics of wife, she and the car are keepers! Good luck!
mchar is offline  
The Following User Says Thank You to mchar For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 09:14 PM
  #3  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

So the basics:

The Vette is a 1979 L48 4-speed. The original L48 motor was replaced with a bone stock Goodwrench 350 motor. In the pictures above it looks to be in good shape, but in reality the suspension was shot, the paint was spiderwebbing and chipped everywhere, and the interior.... Dear God. The carpet was moldy and shredded. The dash was dusty and full of cobwebs. It was nasty.

But did I start replacing the interior first? Nope! The Vette had bald tires, and I knew I wanted bigger wheels and tires, so wheels it was! These wheels are called Ridler 675s. The fronts are 17x8.5, the rears are 18x10. I'm running 255 wide tires up front and 275 wide tires in the rear.





I got the wheels and tires on and (after "relocating" the parking brake bracket.... by which I mean cutting it off and not re-attaching it because I didn't own a welder yet) immediately hated how tall the car sat. So....







I cut the front springs (I believe it was one coil) and installed 10" bolts in the rear leaf spring (Note: I also had to cut the rear leaf spring down and redrill the holes because the stock spring would rub my new wheels). This is the result:




mobird is online now  
The Following User Says Thank You to mobird For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 09:16 PM
  #4  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

Originally Posted by mchar View Post
Pics of wife, she and the car are keepers! Good luck!
Ha she is definitely a keeper! She has helped me pull motors from cars, change timing belts and water pumps, and she owns and rides her own motorcycle. Plus she can drive a manual transmission car like a boss!
mobird is online now  
The Following User Says Thank You to mobird For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 09:27 PM
  #5  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

So now I started to address the elephant in the room: the car looks fast standing still, but it goes slow. SOOO slow. Like unbelievably slow. Turns out there were a couple reasons for that, only one of which was the lethargic Goodwrench 350 (which by the way has 7.8:1 compression ratio.... bleh).

The first thing I decided to address for performance is the same thing everyone tends to do: exhaust. I knew before I got the car that it would have side pipes. Yes I know "sidepipes kill power, blah blah blah". I don't give a One of the main things that drew me to the C3 as a kid WAS the sidepipes, and there was no way in heck my childhood dream car was NOT going to have them. I was planning on getting the cheap OBX side pipes from Ebay (Hooker knockoffs) but at that time, they had gone out of production and I couldn't get ahold of anyone who knew when they would come back. So after researching around, I decided on Doug's headers and Side Pipes and STS baffles.

The STS baffles are dyno-proven to be less of a power restriction than anything other than open side pipes. And Doug's headers have been proven to flow EXTREMELY well, so I went for it. Plus they weigh significantly less than the stock full length system with manifolds (can't remember exactly how much, but I weighed it at the time and remember being surprised)

Beautiful new headers:


Test fitting:











Stock Exhaust removed:




Stock manifolds



Stock HEAVY exhaust

New hotness is on!




Last edited by mobird; 09-20-2017 at 09:31 PM.
mobird is online now  
The Following User Says Thank You to mobird For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 09:53 PM
  #6  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

So now I have a Corvette with sticky modern tires, and some nice flowing exhaust, and a supposed 260 hp Goodwrench 350 in it. Should be at least halfway quick right? Nope. This thing was a PIG. I started researching around and decided I needed to make sure my A/F ratio and Timing were correct. I just couldn't believe a 350 Ci motor could be this weak.

Half the gauges in the center console didn't work. I thought about fixing them, but then decided I wanted something a bit more modern. I also REALLY wanted a wideband 02 sensor to help me tune the carb better. So:



New gauges and new Wideband installed! Felt good to ACTUALLY be able to tell what my oil pressure and coolant temperature was! Thinking back, driving 3 hours on the highway from St. Louis back to KC in this thing without being able to see temperature or oil pressure was probably not exactly smart....

So then I looked into timing and the timing curve (I was learning all this as I went, and Corvetteforum was insanely helpful!). I was told to get Lars papers, and boy was I told right! If any of you haven't read Lars papers on timing and Quadrajet tuning, GO GET THEM NOW!

I already had a distributor with a pretty decent timing curve:



I got the total timing set to 36 degrees at 2800 RPM, I believe initial fell around 16 degrees BTDC. This definitely improved performance, but the car was still a pig. It would practically fall on it's face above 4000 RPM. Mini vans could outrun it, no joke.

So I started working on the disgusting beat up Quadrajet:




It was leaking a bit and had a few vacuum issues, so I ordered a rebuild kit and rebuilt it. And in the process, found where at least some of my mising power was: the secondaries BARELY opened. Partially because the throttle cable was out of adjustment, partially because the top butterflies were rubbing against the top of the carb, and would only open a hair. Like I said earlier, I was completely new to old carbed motors, but I'm learning!

This made a much bigger difference, now the car would pull above 5000 RPM. Still not "fast" but at least it moved a bit. Having driven quite a few cars with dyno proven horsepower, I would guestimate it to be something like 200hp at the wheels at this point.
mobird is online now  
The Following User Says Thank You to mobird For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 10:10 PM
  #7  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

So obviously I was still not satisfied with the performance. I started researching the Goodwrench 350 in my car and learned it had 7.8:1 compression, a TINY cam, bad bad bad flowing heads, and a crappy intake. Basically, not a great base to build from. But I'm a cheapskate and didn't have much money to spend, so I decided to see what I could make of it. I researched and researched and researched what heads to get. Almost bought Vortecs twice, but saving weight was one of the big things I wanted to work on so I decided I would spend a little more and go aluminum if possible. Almost bought some chinese casting heads that had good reviews, until some heads showed up semi-locally (St. Louis yet again) on craigslist: Brodix IK200. I know 200cc ports were too big for my low compression 350 by conventional logic, but I also knew that I planned to eventually go 383 or 406, and those heads would work great on either of those motors, so I saw them as more of an investment. If I remember right, I got the Heads, ARP head bolts, pushrods, 1.5 rockers, and valve covers all for $800 from this guy on craigslist:





These heads have a 64cc combustion chamber which is good for about 1 point of compression over the 76cc stock heads, I also used a Fel Pro .015 shim head gasket which was worth about .5 point of compression. So figuring that that got me to about 9.3:1 compression (halfway respectable. And I later cc'ed the stock cast pistons and verified the compression ratio) I purchased a Lunati 268 (60103) Hydraulic Flat Tappet cam and lifters, and found a used Edelbrock 7104 Performer RPM Qjet on ebay. Checking out other engine builds with similar specs, this should put me in the 375-400hp range at the motor. So roughly 300 at the tire with a 4-speed manual transmission.

So on to the fun stuff: tearing down the motor!




Stock Goodwrench 350 together for the last time...



Carb off



Intake Off



Heads off



Dang... that is a deep dish pizza... I mean piston...



Cam coming out



Old cam out.



All old parts are off. I didn't get pictures of this, but there were HOURS of cleaning off the old block to prep for the new heads. With only a .015 shim head gasket, there isn't much room for error, so I wanted to make sure the sealing surface was perfect.
mobird is online now  
The Following User Says Thank You to mobird For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 10:20 PM
  #8  
chstitans42
TheCorvetteBen
Support Corvetteforum!
 
chstitans42's Avatar
 
Member Since: Feb 2007
Location: Anna Texas
Posts: 4,948
Thanked 69 Times in 44 Posts
Default

Read this from the beginning to here in one go! Keep updating!
chstitans42 is offline  
The Following 2 Users Say Thank You to chstitans42 For This Useful Post:
KNOT-HEAD (09-27-2018), mobird (09-20-2017)
Old 09-20-2017, 10:29 PM
  #9  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

Now the fun part, assembly!





Fel pro shim gasket on!



One head on!



Both heads on!





Pushrods in, intake gasket on! Don't ask about the red silicone. It works fine, but it looks terrible where you can see it. Beginner mistake.



More red silicone



Intake on!



Quadrajet and water pump on!



Everything back together!

Little tip: I used copper gasket spray on the shim gasket and it hasn't leaked a drop in the last year or so that it's been on.


I had a moment when I was doing this where I stepped back and was like "wow, I'm bolting aluminum heads and putting a cam onto my OWN c3...". It was a childhood dream come true, even if my childhood wasn't THAT long ago, it still felt special.
mobird is online now  
The Following User Says Thank You to mobird For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 10:29 PM
  #10  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

Originally Posted by chstitans42 View Post
Read this from the beginning to here in one go! Keep updating!
Thanks for the encouragement!
mobird is online now  
The Following User Says Thank You to mobird For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 10:32 PM
  #11  
bazza77
CF Senior Member
 
Member Since: Jul 2010
Location: perth western australia
Posts: 1,372
Thanked 202 Times in 193 Posts
Default

Nice , what cam went in ?

Last edited by bazza77; 09-20-2017 at 10:33 PM.
bazza77 is offline  
The Following User Says Thank You to bazza77 For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 10:44 PM
  #12  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

So once I got the new motor (or at least top end ) put together, I ran the appropriate break in oil for the new cam and lifters, changed the oil again, set my timing, and learned that my carb tune was now way off! Back to Lars papers....:




Top off the carb AGAIN (probably the 10th time)



Turns out my primary hangar was bent



Got it back in shape and adjusted


Once I finally got the carb dialed in (or as good as I can dial in a carb), it was time to see if it had made any difference in power:

https://www.youtube.com/watch?v=kvfS...ature=youtu.be

I'd say that's a difference

car FINALLY had some power to play with. In the video I pretty much just planted my foot and shifted around 5000 RPM, and it turned out that the carb needed ALOT more work to get it right. It's significantly faster now than it was back then (and lighter) but we'll get to that later!

Last edited by mobird; 09-20-2017 at 10:45 PM.
mobird is online now  
The Following User Says Thank You to mobird For This Useful Post:
KNOT-HEAD (09-27-2018)
Old 09-20-2017, 10:47 PM
  #13  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

Originally Posted by bazza77 View Post
Nice , what cam went in ?
Lunati 268 (60103) its a 227/233 duration at .050. About .500 lift cam. Nothing crazy, but a world of difference from what was in there or what comes stock in an L48!
mobird is online now  
Old 09-21-2017, 12:29 AM
  #14  
bazza77
CF Senior Member
 
Member Since: Jul 2010
Location: perth western australia
Posts: 1,372
Thanked 202 Times in 193 Posts
Default

Originally Posted by mobird View Post
Lunati 268 (60103) its a 227/233 duration at .050. About .500 lift cam. Nothing crazy, but a world of difference from what was in there or what comes stock in an L48!
I agree , the L48 I had in my 77 was a little tired as well , so probably worse than yours

great story
bazza77 is offline  
Old 09-21-2017, 08:20 AM
  #15  
Jeff k
CF Member
 
Member Since: Oct 2016
Location: Ashtabula Ohio
Posts: 97
Thanks: 0
Thanked 23 Times in 22 Posts
Default

Excellent adventure!
Jeff k is offline  
Old 09-21-2017, 08:52 AM
  #16  
Rescue Rogers
CF Senior Member
Support Corvetteforum!
 
Rescue Rogers's Avatar
 
Member Since: Oct 2015
Location: YUPPY HELL Westford MASS
Posts: 4,145
Thanked 557 Times in 517 Posts
2016 C3 of Year Finalist
Default

Im putting Comp Cams version of that cam in my 327. Good to see I made a good choice
Rescue Rogers is offline  
Old 09-21-2017, 08:58 AM
  #17  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

Originally Posted by Rescue Rogers View Post
Im putting Comp Cams version of that cam in my 327. Good to see I made a good choice


I love it. The real meat of the powerband is up higher than most would want for a street driven car (in my case that is probably due to the 200cc heads just as much as the cam choice), but having a 4-speed with 3.55 gears I've learned to love it. Still plenty of power to roast the tires at low RPM, and when it gets above 3000 RPM it SCREAMS!


I'll get a new video sometime soon of how hard it pulls at higher RPM. Pretty impressive for how basic it is.
mobird is online now  
Old 09-21-2017, 12:09 PM
  #18  
Bikespace
CF Senior Member
 
Bikespace's Avatar
 
Member Since: Mar 2017
Location: Vienna VA
Posts: 882
Thanked 135 Times in 124 Posts
Default

Wow, that is some great work so far. Kudos to you for doing a head and cam swap in the car, without it escalating to an engine-out, while I'm at it, multi-year restoration.

Did you address your gasoline smell? It turns out the problem with my '80 was a bad fuel pump, leaking through the diaphram and out the weep holes, but mine came with an EVAP can, mostly hooked up.

I hope you and your wife enjoy the car. I'll be following your thread, as I have two similar cars with similar issues. Hopefully you can save most of your interior, and freshen it up with a new carpet. Oyster is favorite.

Good luck!
Bikespace is online now  
Old 09-21-2017, 12:45 PM
  #19  
mobird
CF Senior Member
Thread Starter
 
mobird's Avatar
 
Member Since: Mar 2016
Posts: 981
Thanked 145 Times in 126 Posts
Default

Originally Posted by Bikespace View Post
Wow, that is some great work so far. Kudos to you for doing a head and cam swap in the car, without it escalating to an engine-out, while I'm at it, multi-year restoration.

Did you address your gasoline smell? It turns out the problem with my '80 was a bad fuel pump, leaking through the diaphram and out the weep holes, but mine came with an EVAP can, mostly hooked up.

I hope you and your wife enjoy the car. I'll be following your thread, as I have two similar cars with similar issues. Hopefully you can save most of your interior, and freshen it up with a new carpet. Oyster is favorite.

Good luck!

Thanks for the comment!


I did (or at least I think I did, it's definitely better than it was, but I don't think it will ever be perfect when I'm running side pipes and no catalytic converter). It ended up being a cracked line between the carb and charcoal canister. Replaced the line (and the whole canister actually since mine was old) and the smell is MUCH reduced.


Ha well one of my next posts will be what I've done with the interior. You might be disappointed as not much of it was saved! I still have some oyster left though, but I may be dyeing it black in the near future since the oyster is still pretty beat up.
mobird is online now  
Old 09-21-2017, 09:45 PM
  #20  
Bikespace
CF Senior Member
 
Bikespace's Avatar
 
Member Since: Mar 2017
Location: Vienna VA
Posts: 882
Thanked 135 Times in 124 Posts
Default

Well, a partial win is still a win. I'm glad you were able to solve most of the gas problem. Running a car with no cats is a smell that you will never forget, though.

I'm looking forward to the interior post.
Bikespace is online now  

Thread Tools
Search this Thread
Quick Reply: My 79 Hotrod Project Build Thread


Sponsored Ads
Vendor Directory

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: