L78 rebuild
 

Hi All,
I am a new member but an old car guy LOL. I am going to rebuild my orignal L78 engine in my 1969 Nova SS. The car is very orignal with the complete original drive train that has a colunm shift turbo 400 and 3:55 gears.
I want to try and keep the value of the car at the market level or more going forward, based on how this engine should be rebuilt to accomplish this. The engine has never been rebuilt before but can use it to preserve it.

Having said that should I rebuild this engine to exact Chevy factory specs knowing that the gas here in Ca. is nothing to get excited about octane wise, or for the sake of the engine itself, rebuild it with lesser compression pistons but with a cam that could still deliver as much HP as I can obtain? I have no problem in adding an octane booster as required as I do for my '68 435 HP Vette rebuilt to complete factory specs. I will probably sell the car when finished to purchase an L78 4 speed Nova or 69 Camaro.

I do intend to have the car as an occasional cruiser and not beat on it in any way but I like some decent HP when I want it. Any thoughts and suggestions would be deeply appreciated.
Thank you,
Joe

If value is the goal, I would stay stock across the board. Compression, cam, valve size, etc. When is comes to sell, you can its all stock. That is always better than its stock "but".......

Not to mention, the compression give the the pop that is so exciting.


Jason

I agree with Jason. I would rebuild it 100% stock and do a good job keeping all the box flaps of all the parts your engine builder used. In addition to the box flaps identifying the parts used have your engine builder detail out what he did, and of course keep all the receipts. When I had my 67 Vette engine rebuilt I got the above and a worksheet from the builder.

And don’t under any circumstances deck the block where the front pad stampings are!

I want to add: I would de-grease the block, and if it is not all carboned up or sludged up on the inside, I would clean it myself using a power washer, degreaser and a rifle brush kit to clean passages. My reasoning for doing this yourself is there may be paint markings on the block from the factory and I would want to preserve these and that goes to my next point that I would shy away from painting the engine, that is, if you are interested in keeping the value up of the car. Just my opinion.
Last : if you are just taking the car to shows, cruise ins, etc...and not a daily driver, I would not put stellite seats on the exhaust valves.
Have everything manufluxed, money well spent. Static balancing the rotating assembly is one thing I would advocate that is not part of a “stock” rebuild.

as those above said, keep it stock, keep it 11:1 compression if you're not going to drive it much. The engines are so much fun with that power. Keep a tankfull of 110-110 octane fuel in it and you'll be fine. That gas lasts for a long time. Nothing like the "pop" of a high compression engine firing off, dial all the timing in by 3k RPM and it will put a big smile on your face. Good luck with it!

Been running my L78 all stock compression for years on 94 octane with conserative timing with no problem

X2

l78 rebuild
 

Hey Joe,

I sometimes take my L78 Nova to San Clemente C&C so look me up if you go. My 19K original mile L78 does ok with 91 and a 9pt boost of VP Octanium. No issues. I have all advance in before 3200rpm.

I would keep it all stock in doing a rebuild.

Mark

I just rebuilt the 427 in my Camaro this summer and went from 9:1 to 11:1 with total timing at 35 degrees and all in my 3500. I run alcohol free 91 octane and it's doing fine.

L78 rebuild...
 

These cars are all about...I repeat, all about the 11 to 1 compression. Lowering the CR would be a mistake...just find the right fuel and enjoy.

A stock rebuild should include a careful review of the valve train components...they were the weak link and one of the reasons we have so many CE motors in cars like this.

As mentioned make sure the deck stamp is protected...take photos for insurance and make the shop understand you don't want it removed.

Lots of times these engines actually had less then the advertised 11:1...so you may find a few extra ponies in checking the CC's on the heads and confirming the ratio.

A thorough professional job will protect and value to the car in the years ahead.

-wilma