78pace

tossing around the idea of a weiand 142 supercharger. The kits list for use with long water pump. does my 1978 have a long or shot pump? If a short pump what would be a work around for the supercharger kit listed for a long pump. Summt has one kit satin or polished for vortec heads and both are listed for long pump thanks

73StreetRace

Information found in the Edelbrock catalog :

Chevrolet used a short water pump on small block passenger car engines from 1955-68, 1969-70 350 Corvettes, and 1955-72 light duty trucks.
The dimension from the engine block surface to the water pump hub is 5 5/8". The pilot shaft diameter is 5/8".
Long water pumps were used on small block passenger cars engines from 1969-87 and on 1973-86 light duty trucks.
The dimension from the block surface to the hub is 6 15/16". The pilot shaft diameter is also 5/8".
However, 1971-82 Corvettes have a short water pump with a larger 3/4" pilot shaft.

Hope this helps !

Mike Ward

Yes it does help because it recognizes that these year of cars have a specific pump.

SteveG75

From the Weiand Site:

PART #: 6508-1 - Short Nose 142
Installation Notes: Will work with one or two V–belt accesory drive Pulley systems. Not compatible with serpentine accesory drive systems. Short nose kits fit short water pump applications. This kit can also be used for tight clearance applications such as Street Rods.

PART #: 6500-1 - Long Nose 142
Installation Notes: Will work with three V–belt accesory drive Pulley systems. Not compatible with serpentine accesory drive systems. Long nose kits fit most short and long water pump applications. Slight elongation of four center holes may be required for 1987 and later cylinder heads. Will not fit 1984 to present Corvette due to rack and pinion clearance problems. Will not fit 1992 or later LT1 engines. For Vortec or Fast burn heads see 6542–1 or 6543–1.

So, the real issue becomes how many V-belt pulleys on the crank hub are you running. 1-2, get the short nose, 3, get the long nose. The real difference is where the the supercharger belt is in relation to the crank dampner, not the water pump.

Now, Weiand (Holley) does not list a short nose for Vortec heads but the difference would be the lower manifold, not the supercharger (and nose). If you want a short nose for Vortec heads, I would contact Weiand and see what they could do for you.

The intake manifold is available separately so a swap should be easy to do. I even found out that Weiand has a manifold with EGR for the CA smog *****.

pws69

I have these specs in a document I have had for several years. It also notes that there is a slight block to face measurement difference.

Short-Style Pump for most 1955-72 cars & trucks
(5/8" pilot shaft)
• Fits all 1955-68 S/B Chevy passenger cars, 1969-70 350
c.i.d. Corvettes and 1955-72 light duty trucks. Has 3/4"
ball/ball bearing.
• Dimension from block surface to hub: 5-5/8".
Inlet diameter: 1.80".
-------------------
Long-Style Pump for 1969-87 V8, 90° V6 & 1973-86 truck
(5/8" pilot shaft)
• Fits all 1969-87 S/B Chevy or 90° V6 passenger cars and
1973-86 light duty trucks. Does not fit Corvettes (use #8810
or #8812) or late-model vehicles with serpentine accessory
drive belts (use #8881). Has heavy-duty 3/4" ball/roller
bearing.
• Dimension from block surface to hub: 6-15/16".
Inlet diameter: 1.80".
-------------------
Short-Style Pump for 1971-82 Corvettes
(3/4" pilot shaft)
• Fits all 1971-82 S/B Corvettes. Comes with heavy-duty
3/4" ball/roller bearing.
• Dimension from block surface to hub: 5-13/16".
Inlet diameter: 1.80".
-------------------

wev

Mine is a late 77 and has a short pump (new) and works/fits fine

SteveG75

Guys, the OP is asking about superchargers. The water pump's only effect is pulley location.

We have a short water pump, but he can use the long nose supercharger if he has 3 pulleys at the crank. If he is only running 1 or 2 (say, no PS), then he should use the short nose supercharger and talk to Weiand about swapping the regular manifold for the Vortec manifold.