68 needs new motor, should I replace the radiator?
 

So the motor in my 68 step side long bed was blown when I bought it. So now I' am buying a blueprint 350 . Some people have said they run hot (blueprint motors). So should I also replace the stock 50 yr old radiator? If so what one should I use. thanks for any help on this.

Re: 68 needs new motor, should I replace the radiator?
 

Welcome to the board from another Iowa boy, and former bee keeper....

What engine did it have in it originally? There are 3 different radiators for these trucks, 2 core 3 core and 4 core.

LockDoc

Re: 68 needs new motor, should I replace the radiator?
 

A new engine is a major expense. A new radiator is cheap insurance.

I have a friend who owns a machine shop that builds high-performance engines. He won't warranty an engine if the radiator hasn't been replaced.

As far as what one, the newer aluminum ones cool well. Make sure you get one that has metal tanks. This is the one I used, and it fit pretty well:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Re: 68 needs new motor, should I replace the radiator?
 

it was born with a 327, blown by 1st own. The 2nd owner had a 305 in it and she blow it. I would love to put a 327 back in it but, the one I bought had a crack in the block under the manifold. So now I' am just going with something new. Its been seating for 30 yrs.

Re: 68 needs new motor, should I replace the radiator?
 

the one I bought had a crack in the block under the manifold

A lot of SBC die this way. Lack of antifreeze, caused the cracks.
My brother had a 350 crack, in the shop, without a water pump on it.
That one cracked at the bottom of the water jacket.
I never forgot his lesson.

Back in the 80's I had the heat exchanger on my 70 GMC fail.
Took out the transmission twice. I didn't know why the first one failed.
Figured it out when the second one went out. It was a junk yard transmission.
If I would have had the first one rebuild the transmission shop would have known.
Water/antifreeze causes the friction material to come loose from the steel backing.
So to be safe I would re-core or replace the transmission as a preventive measure.
Cheers.

Re: 68 needs new motor, should I replace the radiator?
 

A 327 is doable.. A 350 is just a stroked 327, they both have 4.00" bores. The 350 and late 327 has the same main journal diameter, while the early 327s have a slightly smaller main journal diameter. Both 327 crankshafts are available aftermarket. If the 327 you have is a late model, all you need is a "hen house variety" 350 block.

To answer your original question... Cheap insurance, put a new radiator in it and be done with it.. Actually, you can't have too much radiator.. Put a 3 core in it and have cooling room if you decide to add horsepower in the future...

Re: 68 needs new motor, should I replace the radiator?
 

http://https://www.67-72chevytrucks....1&d=1678001696I just put a blueprint motor in my 68, runs 180 all day long. I did have the original radiator recored though so I do basically have new radiator.

Re: 68 needs new motor, should I replace the radiator?
 

You can find a radiator shop and have it cleaned. The brass radiator is the best you can get these days compared to the plastic tank and aluminum core. When I worked in a shop that was one thing we always did when replacing a new engine. We replaced all of the hoses also. I found running a 160 t stat thru break in helped from overheating in a new engine.

Re: 68 needs new motor, should I replace the radiator?
 

Yes, a 30 year sitting radiator should be replaced or re-cored. Also new water pump and thermostat. Use antifreeze. I have never understood straight water in something that wasn't a race car. Straight water freezes and bad things happen as you see. Be sure to follow the cam break-in instructions if it has not been broken in yet.

Re: 68 needs new motor, should I replace the radiator?
 

from your picture it looks like you have 3 on the tree , what headers are you running?

Re: 68 needs new motor, should I replace the radiator?
 

Short answer: Yes
Long answer: Absolutely.

Re: 68 needs new motor, should I replace the radiator?
 

Yes

Re: 68 needs new motor, should I replace the radiator?
 

thanks for all your input guys ! a new radiator it is!

Re: 68 needs new motor, should I replace the radiator?
 

I agree replace or get your original redone and I'd get a new heater core or get the original rebuilt at the same time. Just finishing up a new engine build and had my orignal 3 row rad redone to a 4 row and had the original heater core recored. If u don't do something with the 50 year heater core it will be the weak spot in your cooing system and if lets go it gets messy, stinky and you'll need new carpet too. A lot of choices for rads and lots of people have had good service from the aluminum ones but I wanted the original look for my truck. See the crap in the heater core box and my truck was garaged for most of its existence before I bought it.

Re: 68 needs new motor, should I replace the radiator?
 

OP

while the original radiators had 2, 3 or 4 rows depending on engine size....a radiator with fewer but larger cores works better. I have a BPE in my Camaro and got a Cold Case radiator. 2 x 1 1/4" rows with stock fan shroud. I use a 18"-7 blade fan with fan clutch. No cooling issues. A new design fewer but larger core radiator is better than any new or rebuilt smaller core radiator, period.