Hello,

I'm going to purchase a well kept 1975 corvette. Clean inside and out, top to bottom. This is the 4th or 5th vet I've looked at. The price I feel is reasonable and this has been something that I've wanted for many years now.

Overall the vet is in great shape except the engine is burning oil and leaking from the bell housing, even after he insisted the engine was rebuit recently, but was honest about the issue. This is not a huge concern for me, i have a nearly new motor sitting in my garage. My delima is, the new motor is basically a '92 camaro TBI engine, efi with complete dynamicEFI setup. I could roll this back to a carb setup or to a TPI setup as I have the ECU and full TPI. New engine is a performance engine, vortec heads, Keith black piston and other quality parts that I have receipts for. Yes I will need a new intake about $500. I hand built this engine and tuned it before pulling from my old C10 project.

As far as I can tell engine and vin are original matching. I was not able to verify transmission. I'm not a purist.

This vet will be a Sunday driver in Southern Cali. Not planning on any points shows, maybe the local car club show.

Thoughts on moving to EFI on a C3? Or should I rebuild and put the original back in?

thank you.

 

You answered your own question...
Put that new motor in and turn the old one into a backyard planter...

 

Sure, but do I keep the EFI or stick with carburetor? That's my real dilemma...

Will send pictures tomorrow once she's sitting in my driveway.

 

Side view on transport.


Interior Clean, seats need some work but overall clean and everything is working.

 

Looks nice...
Have you looked at the trim tag to see what the original color was? No black in '75...

 

have fun with it!!

 

That car screams hotrod... Go with the High Performance motor, personally I'd stick with a carb but either would do...

What is the rear? 3.55 would be nice...:

60

 

The trim tag has been painted over. However, closer inspection around door trim seems to indicate it may have been white.

 

I don't know the rear end ratio, excuse the noob question buy is it posible to find out from a stamp or vin code?

 

Well finally got 30min to really sit down and go through the corvette. After I unloaded the vet from the tow trailer it was pissing out coolant from the radiator hose. So glad I didn't try to drive it 3hrs home. It was just a loose hose fitting.

on cold start it burns a ton of oil, owner says 5k miles from last rebuild so either bad rings or head gasket is leaking or cracked block. I'll pull the plugs and see how many plugs are fouled. I'll check the torque on the head bolts too.

looks like the heater hose was bypassed. Melted by headers. Possibly while driving and maybe over heated the block and cracked it.

it's looking more and more like an engine swap.

This is a 2 bolt main, and the new one is a 4 bolt main so if the block is hosed so be it.

 

Hi,
There is a code by the spring and the cover on the bottom of the differential, codes are below. But since you have to jack it up to crawl under there, get both wheels off the ground, put a mark on the drive shaft and on one tire, spin the tire one turn and count the revolutions of the drive shaft...3.5 revolutions would be 3.55-(hard to be exact)....

Differential Codes

60

 

What does that mean, define a ton of oil and how is it exiting the engine. I would get this car sorted out to the point of being able to start and drive it so you can properly troubleshoot the engine. Might be something that is a simple fix.

 

Lots of blue smoke until warmed up. Plus several drips while idling for just a few minutes.

It was more than 2 quarts low when I checked it.

Also might be valve seals if I recall. Once they warm up and expand a bit they stop leaking.

After work today I'm gonna let the car run for a good bit. After i put oil in, and put some card board down to guage the leak.

 

Are you free to do whatever you want in CA with a 75 C3?

Any LS engine you can find will also have EFI, and you still have to do the same stuff to the gas tank.

 

CA only smog checks '76 and newer vehicles. Which is why I was looking for '75 or later corvette.

I have an engine already from a prior project that the body and frame was too far gone for me to fix. It was originally TBI but I have a TPI setup sans an intake. I contacted Howell EFI and they confirmed they can make a harness for me and Customize it as needed.

Yes sending unit and electric fuel pump upgrades for the gas tank will be needed. This won't be my 1st carb to EFI conversion but is my 1st corvette conversion if I decide to move forward.

I've got a list going once I'm sure I can acquire all the parts I will start assembling.

I'm hoping i can get this engine going without the smoke and do the swap after summer so i can enjoy the corvette before the heat sets in.

Friday I will dig and narrow down the oil burn and leaks.

Thank you everyoje for the great feedback!

 

Two separate oil related issues going on here.

Lots of blue smoke on startup would point me to valve seals needing replaced as the low hanging fruit. I had this issue with my 73 and valve seal replacement seems to have fixed that, it is an easy task to perform if you have the proper tools and follow the correct procedures.

Several drips while idling doesn't sound like a typical rear main seal leaking, I would look at the oil pressure line fitting at the back of the engine, valve covers etc. for starters. Should be easy enough to locate the source of the leak if it's leaking that much oil.

 

pull the intake and do an autopsy on the manifold gasket. get a carb intake for the vortec heads. run that (now) paid-for q-jet. then decide later what efi you want to use. the numbers-matching block is a collectors item. you have to go back to 1953 to find a lower stock horsepower rating. numbers-matching 75 means nobody spent money on an engine that car deserved...

 

Oil pressure line, okay, didn't consider that but will check.

Thank you!

 

Will a q-jet fit on a TBI intake? If so then I have a vortec intake i can use.

 

Probably not. What does the mounting flange look like? To run a Q-Jet with Vortec heads, you'll need a spread bore intake made for Vortec heads. Like an Edelbrock Performer 2116:

https://www.summitracing.com/parts/edl-2116