VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 Water Pump exchangability

I have a 1948 Chevrolet cabriolet that is completely stock with the exception of the engine which is a 1956 235 painted the same color (gray). I bought a water pump that is a 1948 off e-bay. Will the 48 water pump fit the 56 engine?

No-The water pump up thru 1954 bolts unto the front of the block.The 1955 and up pump fits into the front of the block.

When doing a swap from 216 to 235,I've always used '54 engines to avoid the water pump issue, but I've been told that the water pump issue can be done two ways. The good way and the bad way. Gene, can you fill me in on this...Joe

Hi Jim; I've used an adaptor plate on a '59 235 that's going in my '46 Chevy. It keeps the fan in the stock location and you are using the stock(216)pump and pulley. There is a fellow out west that sells them on ebay for 40 US.It seems to me I have to use my 216 harmonic balancer also. Not that far yet, just painting the engine before I drop it on the chassis. if you're interested I'll email you the guys address and also the instructions. This would give you a better idea.Cheers!!! John

Can't answer this in detail since its a modification.....Patricks sell a short shaft and pulley for the 1955 and up water pump.This enables the later engine to be installed in a pre 1955 with out moving the core forward.The 1955 pump pulley is larger than a 1954 as the impeller is larger and the pump must turn slower.I believe thats the "good way".Also the large blade slow turning 1955 fan shold be used.The complete short water pump can be purchased from Pataricks as a unit for about $150.00

I would prefer the 1953-54 engine myself as it would look more "stock".

Chev Nut; Have you seen a problem with using the adaptor plate or is the modified water pump just a personal preference. Just wondereed before I drop in the 235. Thanks.

I have no opinion (thats a first)-and no real experiance with either.Not even sure what the adaptor plated does.Clue me in.

1955-62 Water Pump Adaptation

When installing a 1955-62 235/261 full pressure engine in place of a 216 or early splash 235 engines, this one time conversion allows you to put the early style pump on the later engine.

In the past modifying the 1955-62 water pump was done but required a press to force the hub further back on the shaft, then the hardened shaft that was left protruding required being cut off. Additionally a special pulley and fan was required. After all that the pump and fan still sat 3" lower than the 216/early 235 pump that could lead to overheating and possible fan hum.

By using this adapter with a 1941-54 water pump the pump is put back in the stock location*. If you need to replace the water pump in the future you can buy an over-the-counter pump and install it without modification.

This adaptation requires drilling and tapping two holes in block.

Note: I recommend using the harmonic balancer and water pump with the belt width you want from your original engine.
1941-52 ⅝" belt
1953-54 ⅜" belt (A 1955-62 truck balancer which is designed for a ½” belt may be used with a ⅜" belt which will allow the belt to run deeper in the groove which in affect will reduce the diameter to very near the correct size).
1937-40 must use one of the above

Caution: Do not use the 1955-62 PASSENGER balancer since the pulley is larger and will turn the pump too fast.

* Stock for 1941-54
* 1937-38 fan will be ½” back from stock.
* 1939-40 Belt and fan will be ¼” forward from stock but will fit fine.

You heard it from the horses mouth guys. I ain't the brightest bulb on the christmas tree and I had no problem at all installing it on my '59 235. Once the block is painted you really have to look to see that there is something diff. on there. All that I can say is it worked for me and I'm very happy with it. It was the best 40.00US I ever spent. Hope this helps you out.Cheers!!!

I'm temporarily out of these adaptors, but if you would like to see a picture of one installed you can look at eBay #4594338078 to see one.
Dave