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PAC Racing Valve Spring Height Gages

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Post Options Post Options   Thanks (1) Thanks(1)   Quote PROSTOCKTOM Quote  Post ReplyReply Direct Link To This Post Topic: PAC Racing Valve Spring Height Gages
    Posted: May/23/2020 at 2:15am

So I had some stimulus money burning a hole in my pocket and I decided to buy myself a super fine PAC Racing installed valve height gage. Before I start I’ll show a photo of them I took in ascending order from left to right part numbers, PAC-T901, PAC-T902, PAC-T903, and PAC-T904

I am currently working on a set of 440 heads and the springs I am using have an installed height is 1.85" which is a lot shorter than I am used to using, so I look at the PAC listing and I see. "PAC-T904 Installed Height Gauge - LS & Duals 1.400-2.000 Range Purple" Great that looks like the one I need because I am using K-Motion K800 dual valve springs. Right? WRONG!!!  The hole in the top of the gage is only .995” and my Comp Cams 1730 retainer has a 1.065” step, so this isn’t going to work at all. Time to send it back right? Nope So after this tool sits around growing on me for a few hours I reason that, Well I'll just keep it and use it on a single spring retainer if I ever need it and start looking for the one I need.

So here we go again!! I look at the chart again and I see, "PAC-T902 Installed Height Gauge - Pro Series & Drag Race 1.800-2.600 Range Red" Alright this one will do the trick since I am not normally playing with a spring with an installed height of less than 1.800" anyway. So I order this one and I am all happy. Then later in the afternoon that day it hits me that I have made a big mistake because I forgot to account that while the gage will technically adjust to 1.800 it will not fit the range I need because you have to crank it below your installed height by at least .200"-.250" to have room to get the valve keepers in the retainer depending on your valve and retainer combinations. This means I need around 1.600" before it will work. Screwed up again!!!  At this point I hate to admit how much money I already have spent for something I really didn’t need in the first place, but wanted so onward we go.

Now I am only left with two other options at this point and after looking at the PAC chart again I know the T-904 is for Beehive retainers, so that one would be really small so I order, “PAC-T903 Installed Height Gauge –Engine Builders 1.400-1.900 Range Orange”. Boys and Girls we have a winner here. The old saying, “Third time is the charm” never rang truer. Had PAC even bothered to have any dimensions at all on their website I could have just bought this one from the start it would have saved me a whole lot of time and money. I always tell people education cost. How much are you willing to learn? Well I am now an expert on PAC installed height gages and I paid the price to learn all about them.

I will note that the T-902 and the T-903 both have a 1.195” second step diameter and a .950” third step diameter.

At this stage I now have three of them sitting on my desk and being the kind of guy that likes complete sets of tools I thought, you’ve already spent a fortune why not and go for it and went ahead and ordered the last one, “PAC-T904 Installed Height Gauge- Beehive 1.400-2.000 Range Blue” and completed the set. Note this one has a second step i.d. hole of .755”.


Hopefully this review will educate anyone that might be thinking of buying a height gage and really has no experience with them. I’ve been using telescopic bore mic or vernier calipers for years to do this job and those have served me well, but just wanted an easier and more accurate way of doing the job without the previous efforts I've used in the past. Also note that PAC calls them a Gauge. It was always my understanding that a gauge has a see thru face with a dial, which really mean they should be called gage/s. Either way if you want probably the finest made gage buy a PAC. They are American made in Michigan from 440C stainless steel, beautiful anodized sleeves with finely cut markings. I checked two different heights with a Starrett 226 inspection grade micrometer and the adjustments are within .002" which is more than adequate tolerances for my needs on a valve spring.



Edited by PROSTOCKTOM - Jul/12/2020 at 6:43am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amcenthusiast Quote  Post ReplyReply Direct Link To This Post Posted: Jul/26/2020 at 9:36am
Cool valve springs and cool tools...

Next thing would be to have valve spring kit specific install height tool with approximate lbs rating at that particular height... where the tool shows the estimated spring pressure of that particular spring at every setting?

-an educational tool, or so the installer doesn't have to do any math, to translate the 1.9 lbs rating into spring rating @ 1.85" etc?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Jul/26/2020 at 4:40pm
I could have used one of these recently, sounds like I avoided some hassles, but now have a guide to work with for next time.
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