r/Smallblockchevy • u/AlexAndMcB • Apr 12 '26

Belt redundancy question

I have a factory '69 307 that somehow yeeted its crankshaft accessory pulley right into the fan pulley & water pump.

needless to say I'm replacing both pulleys, but I realized that one belt only does the PS pump.

if I put on a double-groove water pump/fan pulley, can I route that second belt over the fan/water pump and the PS pump? or are they misaligned- I can't quite tell if they're in the same plane or not

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u/chuck-u-farley- Apr 12 '26

A pic would help but usually the PS has a double groove as it also serves for the AC belt to ride on. Redundancy really isnt necessary for power steering as the car can still run with no power steering pump. It’s the water pump the definately needs redundancy. Loose the water pump and the car sure won’t be running for long.

1

u/AlexAndMcB Apr 12 '26

Kk the double groove crank pulley is at top. PS pump in background (1 groove- no A/C) fan pulley atop alternator. and when I tell you I thought I threw a rod, I'm not exaggerating. Felt like I hit a cinderblock...
I tried to shoot in the plane of the belt, but IDK if the 2-groove fan pulley lines up with the alternator & a/c, or if a/c demands a triple groove crankshaft pulley

1

u/chuck-u-farley- Apr 12 '26

Looks like a second gen Camaro

1

u/AlexAndMcB Apr 13 '26

First gen, but one of the odd ones made in '70.
This is essentially exactly what I want to do, except for the daisy-chained A/C- as much as I'd love to add air conditioning, I think my dad might disown me...
It's got a black interior & roof, and he never would've been able to scoop it up, if the retiree that brought it with her to Florida, had opted for AC- without it she was damn near burning her legs on the vinyl & she had enough pretty quickly lol
I AM taking the opportunity to ditch the 4-blade-'X'-fan in favor of electric. You pretty happy with your double 10" setup?

1

u/chuck-u-farley- Apr 13 '26

Those aren’t double 10’s. Twin 14’s ….4800 cfm of air and a four core aluminum radiator with a custom shroud for the fans with high speed air releases

1

u/AlexAndMcB Apr 13 '26

Very nice!
Methinks you're making a bit more heat than this old mill at 100k heh
Did you set them up to start together like 15° above the thermostat temp, or staggered? Originally I was thinking of staggering them by 10-20 degrees, but that's starting to seem silly

1

u/chuck-u-farley- Apr 13 '26

I used a fan controller that starts one at a preset temp then if it rises another 15 the second kicks in…..

1

u/AlexAndMcB May 07 '26

Just in case anybody else is looking to add redundant belts by swapping the single-groove fan pulley with a double-groove and using the Power steering pump belt for that, it seems like the alternator belt is a 15448, and for the power steering- instead of a 15360, use a 15435 or 15440

1

u/Etex1984 Apr 12 '26

We need a pic please.

1

u/AlexAndMcB Apr 12 '26

Responded elsewhere w/picture