The Stovebolt Site Forums The Shop Area Engine Shop Fuel pump for 1958 six cylinder 235 engine

I ordered a new fuel pump for my 1958 235 engine from a reputable after-market parts supplier and just want to be sure I have the correct item before installing it. My Apache truck came with vacuum wipers. I had the engine re-built many years ago and have not completed my restoration (another story), but moving forward. My son and I are wanting to be sure the engine works as one of our first milestones. The fuel pump installed by the shop that re-built the engine is different than the one I just purchased.

I am requesting that someone post a photo of the fuel pump supplied originally by Chevrolet for use on an engine where the wipers are operated by the engine vacuum.

I do not know if a glass bowl was still used on the fuel side (top side) of a dual-action fuel pump in 1958. The style supposedly changed in 1958.

Here is a photo of a 1957 dual-action fuel pump with no glass bowl on the top side (the fuel pump side). It looks like the difference between the 57 and 58 dual-action fuel pump is the diameter of the two vacuum holes/ports on the bottom half of the pump.

My 58 with the 235 came with vacuum wiper, but did not have a double acting fuel pump on it.

the double acting pump was an accessory, not a standard item

Bill

I think many of the GM engines from the 1950's used the same fuel pump, just different arms for different engines. I have a combination NOS pump in a box that looks the same as a Chevy pump, but has a different arm. Change the arm and it would probably work.

John

Here are some fuel pumps.

It is interesting that GM shows a standard combination fuel and vacuum fuel pump in the 1958 Specifications Manual; however, in 1959 the combination fuel and vacuum fuel pump is shown as standard only on the 235 engine?

The dual action fuel pump had different names, but it was RPO-340 in many years (Regular Production Option - factory installed). Most likely it was also available as an accessory.

of many TF trucks I've seen [mostly 235's] only 1 had the double acting pump [w/o glass bowl], although of course they might have been replaced sometime with cheaper aftermarket pumps ... also note that by 58/9 electric wipers were much more common

Bill

The dual fuel/vaccum pump is AC model BK/BN and was around since the 40's and my manual lists 2 different part numbers for them in total.

The easiest way to ID an AC pump is by the model number stamped on the mounting flange.

Most AC pumps give the same pressure/volume per stroke so really they are mostly interchangeable. As to what is right the Master Parts List may help. I have at least 6 AC pumps to choose from (singe, dual, glass pulsator dome or metal... they all seem to have worked on the 235s that I have.

Good info and thanks to all of you for responding. I ordered this fuel pump from LMC and I had a choice of vacuum or no vacuum. Since my truck originally had the vacuum wipers I wanted to put it back together as original as possible. Wanted to be sure that what I was installing was the right type. It will be a couple of weeks before I am back home with my project and can compare the pump I received with my parts order with the information and photos you folks provided.

Thanks again to all the good assistance an Happy Thanksgiving to all of you!

John

So,On the glass bowl type fuel pump. Does the glass part go up or down? I mounted mine glass down on my untested motor.

It depends on the lever. The fuel pump eccentric on the cam is what operates the pump and the lever arm usually has a bevel on one side and flat on the other (or a pretty obvious pad). The flat side/pad is what rides on the eccentric. Also there is a spring in the housing to keep the arm against the eccentric... so that's another tell as to which way is up.

Almost all of the AC pumps I know of ride 'on top' of the cam, not 'under' it.