High RPM and V-belts

Big block application, just driving alternator and water pump. Street driven car, I want to keep
the alternator and W/P belt driven.

Engine will have 7000~~7200 RPM capability.

At the moment I have a simple OE V-belt setup. I'm just looking ahead to any potential problems,
like maybe some belts are better than others ? Or some different pulley system ?
Curious about using all Gilmer belts / pulleys.

If the pulleys are in good alignment, is that all I really need to be concerned with ?

if you are staying with v belts, maybe a simple belt "retainer" made from 1/2" round stock with some flat stock welded to the end, then bolted to the alternator and water pump approximately 1/8" above the pulley may help retain the belts when they stretch at high rpm.
i have seen this simple idea on several applications. it seems to do the job, so i have stored this idea if i ever need to use it.

Run the shortest, skinniest belt you can.

i've used this idea for decades.

Following this topic because I'm actually having a issue with mine flying off,

I've not had any problems with the factory pulleys and local part store replacement belts staying on at 7000.

I just talked to Powermaster the other day about this for my own project, he said make sure it's straight and tight.

i use March pulleys .
Similar to Lew i have idler pulleys on the upper belt run , no drag and keep a slight tension as it helps wrap a little more on the alt/waterpump pulleys

Tex

That is one thing that has never given me trouble. Running a quality alternator and water pump helps with bearing longevity because they do need to be a little on the toghter side.

I have had good luck with Tuff Stuff and Powermaster alternators.

Milodon used to be my go to water pump however the last batch I ordered were GMB inside of a Milodon box. I find it annoying that you cannot source a high quality as-cast water pump. It is almost easier to run an electric water pump. I look at the mechanical fan as a safety issue when working on an engine.

Jeremiah, what do you like for a water pump ?

What RPM do you shift at ?

If you have an electric fuel pump then you can go with a low mount alternator kit. The low mount kit drops the alternator down a few inches so the belt is much shorter.
http://arengineering.com/products/low-mount-60a-kit-bb/

I have stuff that shifts from 5800 to 7200.

I use CVR 55 gpm electric pumps for a stock style replacement however my preference is an AR Engineering motor plate/water pimp adapters and a remote pump.

V belts on my alternator and vacuum pump spinning to 8400 with no issues. Make sure the pulleys are aligned and the belts are tight and you should be good.

Andy I have that kit but still having issues with belt coming off. But I'm running the stock alternator

^^This^^

My small block has a 5" pulley on the crank and has a Powermaster GM CS121 alternator. I've turned it 7800 and didn't throw the belt. I took a lot of time to ensure everything lined up well when I made the spacer for the crank pulley and the alternator brackets.

I've run a few different configurations w/ V belts consisting of stock size pulleys and smaller underdrive pulleys. All over 7k rpm and never had any issues w/ belts coming off.
I think the biggest issue is making sure it's all aligned properly.

Made one of these for the Satellite. I lowered the alt. 10'' for packaging reasons, and this stopped the belt throwing. Quick. cheap& reliable. Saw an episode of Graveyard
Cars where they had an underhood go-pro camera mounted, and even the factory system showed lots of "whip" in the belts.

Keep the belt as short as possible and as stuff as you can and you wont have any issues. Low mount kits are great for that. The only belt i ever have an issue with the is AC belt on my Camaro but it is a MILE long and dont like anything over 7400

i had an old drag racer show me that "gadget" about 1969. i ran a 4spd car and it would be unreliable belt wise approaching 6000rpm. been using them since. there's a reason the super stock wedges and hemis had deep groove pulleys.

that was exactly the idea i tried to explain. thanks for posting that picture Lew !