71 GMC 3500 longhorn cooling problems

[torquepower]

Hi there, I'm new here. Looks like a very nice board with lots of interesting trucks, people and info.

Just bought a 1971 GMC, sierra grande, 3500, longhorn TH400, eaton rear 4.10, no air, 454 (will fry the tires at will, even rolling) The 454 looks like its from an 88, with 88 long water pump and pulleys and alternator, it also has an edelbrock performer manifold, HEI.

The truck has a 5 bladed fan with really big pitch that sounds like a jet engine when get going over 25mph, after driving for a while your ears start buzz, I'd like to get a clutch and change the fan to a 7 blade 18" diameter, but the shortest one I've seen in the wreckers (consistent with hayden 2705) only leaves about 1/4" clearance to the rad. That seems awfully close. The truck is missing the fan shroud. I'm trying to find out what parts I need to make it work.

Questions;
1> Did these come with short or long pump?
2> Is the BB fan shroud different from others?
3> Where is a good source for pulleys and brackets? The old stuff is rare around here. Are AC setups different on the pump and crank pulleys then non AC units.
4> I have a power steering pump with remote res, is this stock? What is the res attached to stock?
5> What side is the alternator supposed to be on, mines's on the passenger side.

Any help would be appreciated. Thanks.

[dyingdeadman]

i can answer a couple of these questions, the bb shroud is differnt i think but not sure of the difference. the power stearing pump with remote res. is stock and the alternator is on the passanger side for non a/c and on the drivers side with a/c, well that goes for the older big blocks anyway. not sure about the newer ones.oh and you can probely get pully's and brackets from just about any junk yard for your 454.

hope this helps some and welcome to the board.

[longhorn71]

welcome to the board!!!glad to see another canadian longhorn

[tomatocity]

Welcome to the Board.

In my research for a shroud I thought the BB shroud was deeper than a SB. Yours looks very close to the front of the engine bay. Don't BB usually sit closer to the firewall than a SB? Looks like a SB shroud would not fit that setup. Was this truck always a BB? Wish I had a BB so I could send you some pictures. A shroud and clutch fan would help your overheating problems and reduce the noise and increase the power. An electric fan would be an excellent solution.

[RPOZ11]

Hope this helps you...it was late, it was the best I could do...

[Americanrider]

Read post #6 on this thread.... yea, I know you want stock or close to it but the line has been crossed when the '88 454/hei/performer went in and the 402 went bye-bye. In the long run you might be spending a few less loonies per liter.

http://67-72chevytrucks.com/vboard/s...1&page=1&pp=25

[torquepower]

Total fluke. I've found the original owner, he has the original 402 with all the accesories and shroud. I can make it a matching # truck.

I bought this truck from the paper, the guy who sold it to me never transfered ownership, I recognized the name on the registration of someone I met once at the racetrack over 5 years ago. Tracked them down through a friend of a friend.

Who ever said having a short memory is a blessed thing.
Thanks for all your help.

[Americanrider]

Northern Neighbor

That is a tight fit! Have you considered losing the fan and going to a Electric pusher setup? Might gain a couple of horses (not that you need them) but it will save your hearing.

[torquepower]

Originally Posted by Americanrider

Northern Neighbor

That is a tight fit! Have you considered losing the fan and going to a Electric pusher setup? Might gain a couple of horses (not that you need them) but it will save your hearing.

I'd like to keep near stock as best as possible, I'll go electric as a last resort. I used to use electric fans on my oval track stock car and found that mechanical fans worked best.

[Bob Moore]

The 68/72 BB trucks came with short waterpumps. For trucks this means alternator on driver side and A/C compressor on passenger side. Special brackets and pulleys are necessary to convert from long pump. The brackets and pulleys are available just somewhat expensive - a complete set will be $500 plus. It also takes power steering brackets to finish the job.

The big block fan shroud is beefier than the small block - I don't know if the SB shroud will work or not - probably will but not positive.

You will have to ask yourself is the noise reduction worth the $$$

Good luck - Bob

[acloco]

Get rid of the fan....and install an electric...with a thermal switch.

[krue]

Congrats on the find. Lucky dog.

[Canadian694x4]

Welcome To The Board! Great Truck and that's awesome that you were able to track down the original 402!