OK, what are the limitations of combining different harmonic balancers and the two (nominal) sizes of water pumps. For example, if you combine a late model (~85) engine with a short pump, will you be able to find pullies that will line up? Timing tabs are sorta part of the question too. And dont smartass out with " its a SBC, the parts are everywhere" they are increasingly hard to find, especially if you are mixing parts. and whoinnahell can go out and buy all new matching everything? I've got these parts in front of me, paid for.
The pulley mounting surface is at the same place with all the different dampers. So you can use either pump with any of them. You just need the right pulley. The timing cover needs to match the damper, although many of the later ones have a bolt on timing tab instead of being welded on.
OK , one thing you also need to keep in mind is not to accidently install a later water pump with reverse rotation.
As Squirrel stated about the timing, I'd be sure to check the marks by finding TDC with the spark plug out or the timing cover off, if you're mixing parts.
I have an 86 SBC with standard rotation LWP and sourced 'V' belt pulleys to suit. Also have a 90 SBC with reverse rotation LWP (Serpentine) which I swapped for a standard rotation LWP with 'V' belt pulleys to suit. Not that hard to mix and match, just remember SWP or LWP, and standard or reverse rotation. Also as stated timing pointer needs to match your harmonic balancer.
Balancers will work with either short or long pumps. The critical thing is to match timing covers/tabs with your balancer. To be safe I would use the cover and tab that you have. '68 and earlier small blocks used the short pump. Their timing tabs and corresponding timing marks on the balancers were in different locations than later versions. Some later years also used a timing tab that bolted on with two timing cover bolts. As far as pulleys, long pump hardware is a lot easier to find. '69 up cars and '73 up trucks had the long pump setup. Probably the easiest place to find short pump pulleys would be '67 to '72 Chevy trucks. There are still a lot of them sitting around. Hope this information helps. Tim
Mixing and matching can be done, it's not that tough. The hard part is the 7 trips to the parts store to get the right size belts. Speedway Motors and Summit both sell some affordable pulleys.
Short pump pulleys can be had from Chevrolet . They are steel and fit. As said be careful of the balancer and timing tab. Ask me how I know........
I've done that once or twice, now I measure as best I can and get 7 belts to start with. Then take six back - thats only two trips for one belt lol. Now, Treb , what parts do you have in front of you" or what are you missing ? You really can't mix the parts of a Long water pump system with a short water pump system , but most blocks will accept either as a system. The balancers are the same but the timing mark maybe different, you can put your own mark on any balancer and bolt on a pointer anyplace you want or need. I got a crank, water pump, and power steering pulley set in chrome for 80.00 not to long ago. Some of the brackets can get pricey if you can't find them in a bone yard, but they are available. Its the little stuff that will keep you off the road.
Check with www.agcbracket.com, Alan Groves not only makes great accesory brackets but he also sells all of the stock GM pulleys for all applications. I bought them new and it was cheaper than finding old used stuff and cleaning them up.
I ran into the waterpump timing cover issue when I put the 350 out of my son's weecked 79 ElCamino in my 71 GMC and ran the short pump. The timing tab on the 79 engine was straight up and you had to look down behind the long waterpump on that engine to see it. With the short pump for the 71 you couldn't see the mark or get a light to work on it. Here is the link to the stock pump for the 71 350 http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=TFW43106P_0258170655 The only thing is that that one is a bit ugly as it has two hose outlets on it rather than one. Napa shows a Weiand aluminum pump for a 65 Impala with a 327 in it that might work well and look good. http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_3353692_0359357431 Or their rebuilt pump http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=WP_58129_0267399936 I'm not a big fan of rebuilt pumps though. O'Reilly's shows a pot full of short shaft small block pumps http://www.oreillyauto.com/site/c/s...2500+Pickup+RWD&vi=1405426&year=1971&make=GMC
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