Great to hear you're putting the miles on your truck and that it's time now to put the frosting on the cake and add the adaptor plate. For those of you who are just getting started on a restoration, the adaptor plate is used behind an early style water pump to eliminate some cooling issues when replacing an early 235 with one from a 1955 and up.
Having tried both, like so many others and finding that the pricey, so-called "short shaft" didn't address all the cooling and clearance issues, the adaptor plate addresses and corrects them all. First of all, and most importantly, it will raise the waterpump up so that it is centered on the radiator, uses the early style waterpump which can be purchased locally in both 3/8 and 5/8" belt widths, gives you the correct pulley size for correct pump rotation speed, gives you enough clearance to you can run a 6 blade 15" fan for increased air movement, eliminates fan blade clearance issues with the harmonic balancer/alternator/generator/AC compressor and eliminates cooling issues as a threat to your driving enjoyment.
After 5000 miles on my 54 truck with the adaptor plate and after purchasing a "short shaft" pump which didn't address ALL these issues, I feel safe to say that it is the BEST option when cooling your 1955 and up 235 engine in the AD truck.
I've got pictures of the plate, and the instruction sheet in my "Shoebox and Tips and Tricks" albums if you want to check out the installation instructions. Click on "full sized" so you can read the fine print. If you FOLLOW THE INSTRUCTIONS to the letter, you can't go wrong.
And for those of you who are apprehensive about drilling and tapping the two little holes in your block....the adaptor plate serves as a guide so if you follow the directions you shouldn't encounter any problems with getting it properly located. You don't drill into the water jacket...and you tap the 3/8 coarse threads into a 5/16" hole. The block drills easily with a battery powered drill with sharp bits and you just need to make sure you drill the holes straight in. I've installed the plate in both an engine out of the truck and one in place with only the radiator removed. Of course it's easier with the sheetmetal removed.
Virginiafire truck, you just need to use common 3/8" bolts with the standard sized heads on the 2 bolts you use to bolt the pump to the plate. The heads on the bolts you used were for some reason, larger than standard heads and that's why your pump wouldn't fit into the block pump passage. Make sure you have the heads on the inside with the nuts on the outside of the pump. I've also found that if you use a longer 3/8" stud on the driver's side you can use it as a mounting point for your alt/gen belt tensioning bracket. I would also suggest using #2 permatex on the gasket surfaces and not RVT.
I added a 6 blade 15" fan (Summit FLX-1615P @ $24.95) with CENTER-MOUNTED blades that moves a tremendous amount of air at lower speeds and gives you 5/8" clearance from the radiator. The center 5/8" hole needs to be filed out to 1" to fit over the early pump snout and if your scribe a fine circle, you can keep run-out to a minimum. I've idled my truck for 30 minutes with the outside temperature at 90 degrees and my temp stays at 180, which is my thermostat rating. BTW....I use a 7 pound radiator cap and never have had my 25/75 coolant dump into my coolant recovery tank. Fill the radiator so that the coolant just covers the core....no need to fill it all the way up to the neck.
It sounds like you're having a great time with your truck and once you get your cooling issues under control you can quit watching the temp gauge and really enjoy the driving.
Dave
Last edited by Fla54Chevy3100; 07/21/2008 2:31 PM.
