I'm puttin together a 305 for my sons car and have a question. I have pulleys from a 350 that I want to put on the 305 will I have any issues with this? I think they should be the same but not sure. And why I'm on the subject of pulleys I have one other question. When I built my 350 for my car I bought aftermarket pulleys for crank and waterpump. I believe they are 6.6 in diameter. I have had a cooling issue every since I put the 350 in and have checked everything and changed everything I could think of. Its not a major issue so I've just been runnin with it. While driving in town or on highway car runs very cool...no probs as long as running 35mph give or take. When I stop at lights it will jump from 180 to 210 in a matter of 2 minutes as soon as light turns green and I'm moving temp gauge starts dropping. After reading alot of posts on here about underdrive pulleys I've almost convinced myself the only problem I'm having is that at an idle my waterpump is not spinning fast enough to pump the correct amount of water through my block due to the smaller pulleys. Do you guys think this is accurate and if so can I just get a bigger water pump pulley or do I need to get crank pulley too?

 

yep i do believe all 305/350 belt setups are similar so you could swap pullies

and your problem sounds exactly like a underdriven waterpump pulley. its probly not spinning fast enough and getting hot at idle.

you can run a different pump pulley to speed things back up. I'm not sure bigger is better in that case. smaller crank pulleys slow the accessories down, but smaller accessory pulleys speed the accessories up. My underdrive alternator pulley is much smaller than stock and it was needed to keep the alternator spinning fast enough when i added a smaller crank pulley

 

Thanks for input. So what would be correct fix for waterpump issue? Bigger pulley on water pump or change both waterpump and crank pulleys?

 

if the crank pulley is smaller than stock, i'd suggest a smaller waterpump pulley. else go back to bone stock when it worked fine

 

Anybody else??? And can someone tell me what the stock size crank diameter is?

 

Completely normal; especially with an electric fan. Not a thing in the world wrong with that. Since the cooling system boils at around 265-270°, 210° is barely even fully warm. In fact the factory electric fan TURNS ON (recognizes the start of the need for cooling) at about 235°; so at any temp lower than that, in the factory's opinion, the car requires no cooling. The fan TURNS OFF (recognizes that the car is completely cooled and needs no further cooling) at about 215°. Not that the factory would know anything about their cars, or any radical assumptions like that; but it's nice to know.First, establish that there's a water pump issue.

Rule of thumb is, ignore all of that stuff about "size" and "350" and all that. Just put the pulleys that came with the car, back on the car. As a set. That way, as the I Ching says, "there will be no error". If your aftermarket pulleys are the same diameter and line up properly, then you can use them instead. But otherwise, stick with what came with the car, so that there's no problems with belts being slung off or the like.

 

OK first off I respect your opinion you give....you've helped in the past. But there is a problem when your running old school setup...ie belt driven fan and 70's 350 block. Back in the 70's 210* was running hot. So it doesnt matter that its in a 83 body its still running hot when you can watch the temp gauge rising by the moment when in stop and go traffic. My main question here is what size is stock for the crank pulley and water pump pulley? Thanks for your input sofa.

 

No, 210° is fine, for ANY year block. They haven't changed cast iron. I ran my 83 car with a 73 400 block for 12 years or more, with the factory's electric fan programming.

They HAVE changed what "they" think is "hot" or not, in the intervening years, though; hotter is better for emissions and gas mileage (although not so for performance). But that has nothing to do with the year the block was made.

Rather than worry about the pump, you might want to just try a new fan clutch, to get better idle cooling. If you're not running a clutch fan, then that's part of the problem, too. Or, if the shroud is missing.

I don't know offhand what the pulley sizes are though; I just run the ones that came with the car. Been running the same ones (83 car, electric fan) since I bought it, 20-however-many years ago.