68 L78 radiator core

[ccargo]

I've read Kurt's cooling report and still have a question regarding the 68 L78 and the core options. Was K02 available in 68 moving the three core to a four core on a L78/clutch fan equiped car? It seems from the report only A/C equiped cars would have a four core radiator. I'd like to recore my three core to a four core If possible?

[plumL78]

Hello I have a pic. of an orig. 67L78 fan assy still in the car and I tried posting a pic but it says the file it too big.  The orig . 3 core is around 2" and the orig tanks are around 3 1/4" so fitting there won't be a problem for the radiator. I'm not sure how close the clutch will be but from the pic it looks ok. If you want to email me I'll send the pic. to you, Thanks

[KurtS]

Regular Production Option (RPO) V01 was the heavy-duty radiator option and was available with all engines except the Z28 or big block engines.

So, no.
You can install a 4 core, but why? A 3 core will work fine. You may have fan clutch length issues with a 4 core.

[ccargo]

Thanks Kurt, I am just a little concerned with the 4.56 axel ratio and what effect it might have on cooling.

[KurtS]

The axle ratio did not have any affect on the radiator from the factory.
I'd say that if everything is in good condition, it shouldn't be an issue. And just how many miles would you drive with that ratio anyway.

[ccargo]

Well...I was planning on driving it from Indiana to Carlisle next spring

[bertfam]

Well... With a little simple math, let's see how far you can get before you blow your engine up!!


 


1. A 4.56 rear end, with typical 25 inch tires will buzz your engine at 4150 RPM at 65 MPH. (This is assuming you have a 1:1 final drive ratio on the transmission.)

2. Indiana to Carlisle is approx 600 miles (depending on just where in Indiana you are) and will take around 9 hours to get there (again, that's travelling at 65 MPH).

3. 9 hours at 4150 RPM will grenade your engine in approx (insert number here) hours!

It's time to start a pool!!

 

I say you'll get about 1/3 the way there (around 3 hours) before something lets go.

Anyone else care to wager?

But, to be serious, a 4.56 ratio on the freeway (for extended driving) is way too low. You'll be driving at very high RPM's and going through gas at a rate of only a few MPG. Especially since you have a big block. My L89 gets 10MPG with 3.31 gears! It turns just over 3000 RPM at 65 MPH. I can imagine how bad it would be with 4.56!!

You might want to re-think your ratio if you're going to do mostly freeway speed driving. If not, and you only plan on 1/4 mile trips, then go for it!

Ed

[ccargo]

My math works out like this:

L78 M22 4.56 at an avg. 12 second quarter mile will take me 4.8 hours to travel the 600 miles  

I cant change how she was born, and dont think I should

[bertfam]

WOW!! Whoever purchased your car originally was SERIOUS!!

And I agree. Don't change a thing - PERIOD!!

By the way, what kind of gas mileage do you get???

Ed

[ccargo]

I'll let you know this spring at Carlisle about gas mileage The original owner was serious when he ordered the car. Story is he had a little help specing it out from a racing buddy named Dick, also from MO.