73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Lifted 74 on July 06, 2011, 11:45:48 am

Title: Engine Options
Post by: Lifted 74 on July 06, 2011, 11:45:48 am

Looking for some knowledge here, and this may sound pretty stupid.... I bought a 74 ck20. It needs a radiator. The guy i bought it off of told me it was a 400sb. Was 400 a motor option in 74? I don't want to sound like an idiot when i call to get a radiator and they ask what engine and i say 400 and they say 400 is not an option. Thanks for your help

Title: Re: Engine Options
Post by: 74k20 on July 06, 2011, 02:21:00 pm

I had my 74 k20 original sb350/auto radiator rebuilt, yet added an extra row for better cooling due to going to a sb400 this winter.  Then 1 week after the rad rebuild I bought a donor 77 k10 with the sb400/auto that I'm rebuilding.  While trying to use the donor fan shroud, I found the radiator was about 2" taller on the sb400 truck.  Then I noticed the radiator top cap was about flat, where as my 74 is stepped down.  I truly wish I would have waited the week and rebuilt the 400 radiator for the extra 2" added height AND a perfect fan shroud.  Guess I'll live with a  cracked shroud for now.

Title: Re: Engine Options
Post by: bobcooter on July 06, 2011, 05:32:53 pm

Call Auto Zone and tell them what you need. They can tell you quickly if it's right or not.

Title: Re: Engine Options
Post by: beastie_3 on July 06, 2011, 07:29:34 pm

there is no sticker on the core support or glove box saying what came in that truck?

Title: Re: Engine Options
Post by: 74k20 on July 06, 2011, 07:54:48 pm

Picture of my stock 74k20 350/th350 radiator, with factory rad mounting cap, and fan shroud.

Note the drop from the hood latch surface (aka rad mounting cap as I call it)

MJ

Title: Re: Engine Options
Post by: 74k20 on July 06, 2011, 07:57:48 pm

Picture of a '77 k10 sb400/th350 "FLAT" radiator mounting cap, resting on top of the '74.  Radiator was about 2" taller and so was the fan shroud.  Hence ever so slight better cooling for a sb400.  At least this is how I understand these trucks, while researching last year.

MJ

Title: Re: Engine Options
Post by: Lifted 74 on July 06, 2011, 10:38:07 pm

Thanks for the help guys. I'm just gonna pull the radiator this weekend and take it to the local radiator shop and have them tell me which one i need. The engine and front support are not stock.

Title: Re: Engine Options
Post by: 74k20 on July 06, 2011, 10:42:17 pm

So if your existing one (whatever it is) fits fine, just have that same radiator rebuilt and maybe add an extra row for some safety incase you decide to ever go bbc or a warmer sbc.  It was only about $225 to have mine rebuilt with 2 year warrenty I believe.

Good luck.

MJ

Title: Re: Engine Options
Post by: Lifted 74 on July 06, 2011, 11:14:36 pm

Yea, the one thats there now fits great. I'm just gonna take that and get a new one, same size to go back in with an extra row. shop told me between $200 and $225 for new. It also has dual electric fans with a switch inside the cab.

Title: Re: Engine Options
Post by: beastie_3 on July 06, 2011, 11:44:58 pm

These guys have good stuff. Ive had my radiator and fans for a year already and love it.

http://stores.ebay.com/PERFORMANCE-COOLING?_rdc=1